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The DNA target determines the dimerization partner selected by bHLHZ-like hybrid proteins AhRJun and ArntFos  

The DNA target determines the dimerization partner selected by bHLHZ-like hybrid proteins AhRJun and ArntFos

Ichiro Inamoto, Gang Chen and Jumi A. Shin

The molecular basis of protein–partner selection and DNA binding of the basic helix–loop–helix (bHLH) and basic region-leucine zipper (bZIP) superfamilies of dimeric transcription factors is fundamental toward understanding gene regulation.

Date: 2017-03-01

Synthesis of Macrocyclic Poly(3-hexylthiophene) and Poly(3-heptylselenophene) by Alkyne Homocoupling  

Synthesis of Macrocyclic Poly(3-hexylthiophene) and Poly(3-heptylselenophene) by Alkyne Homocoupling

George R. McKeown, Yuan Fang, Nimrat K. Obhi, Joseph G. Manion, Dmitrii F. Perepichka, and Dwight S. Seferos

Macrocyclic polythiophenes and polyselenophenes. Controlled polymerization followed by alkyne end-capping, homocoupling, and PEG attachment allows for the preparation and isolation of conjugated polymer macrocycles.

Date: 2016-12-14

Thin-Film Batteries: Bio-Derived Polymers for Sustainable Lithium-Ion Batteries  

Thin-Film Batteries: Bio-Derived Polymers for Sustainable Lithium-Ion Batteries

Tyler B. Schon, Andrew J. Tilley, Colin R. Bridges, Mark B. Miltenburg and Dwight S. Seferos

Sustainable materials for energy storage are urgently needed due to the increased use of electric vehicles and mobile electronics. D. S. Seferos and co-workers demonstrate a lithium-ion battery cathode that consists of a polymer with biologically-derived pendant groups. Biologically-derived molecules decrease the cost of the functional material and the environmental impact of the device.

Date: 2016-10-16

Carbon Dioxide Reduction: Visible and Near-Infrared Photothermal Catalyzed Hydrogenation of Gaseous CO<sub>2</sub> over Nanostructured Pd@Nb<sub>2</sub>O<sub>5</sub>  

Carbon Dioxide Reduction: Visible and Near-Infrared Photothermal Catalyzed Hydrogenation of Gaseous CO2 over Nanostructured Pd@Nb2O5

Jia Jia, Paul G. O'Brien, Le He, Qiao Qiao, Teng Fei, Laura M. Reyes, Timothy E. Burrow, Yuchan Dong, Kristine Liao, Maria Varela, Stephen J. Pennycook, Mohamad Hmadeh, Amr S. Helmy, Nazir P. Kherani, Doug D. Perovic and Geoffrey A. Ozin

Some Like It Hot: Geoffry A. Ozin and co-workers demonstrate that the reverse water gas shift (RWGS) reaction, driven by a visible and near infrared responsive Pd@Nb2O5 is thermally activated with measured conversion rates as high as 1.8 mmol gcat-1 h-1, in article 1600189. Specifically, the RWGS reaction is enabled by heat generated from thermalization of photoexcited charge carriers in the Pd nanocrystals that function as “nanoheaters” for the entire Pd@Nb2O5 assembly, through non-radiative relaxation of inter-band and intra-band conduction electron transitions. Overall this study advances our understanding of the underlying mechanism of photothermally driven CO2 reduction.

Date: 2016-10-12

Chiral carbene–borane adducts: precursors for borenium catalysts for asymmetric FLP hydrogenations  

Chiral carbene–borane adducts: precursors for borenium catalysts for asymmetric FLP hydrogenations

Jolie Lam, Benjamin A. R. Günther, Jeffrey M. Farrell, Patrick Eisenberger, Brian P. Bestvater, Paul D. Newman, Rebecca L. Melen, Cathleen M. Crudden and Douglas W. Stephan

The carbene derived from (1R,3S)-camphoric acid was used to prepare the borane adduct with Piers’ borane 7. Subsequent hydride abstraction gave the borenium cation 8. Adducts with 9-BBN and the corresponding (1R,3S)-camphoric acid-derived carbene bearing increasingly sterically demanding N-substituents (R = Me 9, Et 10, i-Pr 11) and the corresponding borenium cations 12–14 were also prepared. These cations were not active as catalysts in hydrogenation, although 9–11 were shown to undergo carbene ring expansion reactions at 50 °C to give species 15–17. The IBOX-carbene precursors 18 and 19 derived from amino alcohols (S)-valinol and (S)-tert-leucinol (R = i-Pr, t-Bu) were used to prepare borane adducts 20–23. Reaction of the carbenes 1,3-dimethylimidazol-2-ylidene (IMe), 1,3-di-iso-propylimidazol-2-ylidene (IPr) 1-benzyl-3-methylimidazol-2-ylidene (IBnMe), 1-methyl-3-phenylimidazol-2-ylidene (IPhMe) and 1-tert-butyl-3-methylimidazol-2-ylidene (ItBuMe) with diisopinocampheylborane (Ipc2BH) gave chiral adducts: (IMe)(Ipc2BH) 24, (IPr)(Ipc2BH) 25, (IBnMe)(Ipc2BH) 26, (IPhMe)(Ipc2BH) 27, and (ItBuMe)(Ipc2BH) 28. Triazolylidene-type adducts including the (10)-phenyl-9-borabicyclo [3.3.2]decane adduct of 1,3,4-triphenyl-1H-1,2,3-triazolium, rac-29 and the 9-BBN derivative of (S)-2-amino-2?-methoxy-1,1?-binaphthalene-1,2,3-triazolium 34a/b were also prepared. In catalytic studies of these systems, while several species were competent catalysts for imine reduction, in general, low enantioselectivities, ranging from 1–20% ee, were obtained. The implications for chiral borenium cation catalyst design are considered.

Date: 2016-10-21

S(VI) Lewis acids: fluorosulfoxonium cations  

S(VI) Lewis acids: fluorosulfoxonium cations

Fu An Tsao, Alexander E. Waked, Levy Cao, Jordan Hofmann, Lei Liu, Stefan Grimme and Douglas W. Stephan

Avenues to S-based Lewis acids were developed via the oxidation of aryl-sulfoxides with XeF2, giving difluorodiarylsulfoxides which react via fluoride abstraction to afford Lewis acidic fluorosulfoxonium cations; this acidity is derived from the S–F ?* orbital and has been probed both experimentally and computationally.

Date: 2016-10-28

Silicon nanocrystals: It's simply a matter of size  

Silicon nanocrystals: It's simply a matter of size

Wei Sun, Chenxi Qian, Kenneth K. Chen and Prof. Geoffrey A. Ozin

It is surprising that nanocrystal poly-dispersions of the archetype semiconductor silicon have only recently been separated into size narrowed mono-dispersions. This advance has enabled enquiries into the effect of silicon nanocrystal size on their chemical, physical and biological properties, including (i) surface structure and reactivity, (ii) optical and electronic properties, (iii) chemical and photochemical stability, and (iv) biochemical and cytotoxicity behavior. This newfound knowledge provides an opportunity to imagine what is next for this important class of nanomaterials.

Date: 2016-09-21

Lewis acid catalysis: catalytic hydroboration of alkynes initiated by Piers' borane  

Lewis acid catalysis: catalytic hydroboration of alkynes initiated by Piers' borane

Mirco Fleige, Juri Möbus, Thorsten vom Stein, Frank Glorius and Douglas W. Stephan

A collaboration between the Stephan and Glorius groups describe the selective, catalytic hydroboration of terminal and internal alkynes to (E)-alkenyl boronic pinacol esters using Piers’ Borane, (HB(C6F5)2) as a pre-catalyst. The catalyst is shown to be the dissymmetrically gem-diborylated species RCH2CR’(Bpin)(B(C6F5)2).

Date: 2016-09-14

Pyridinium–phosphonium dications: highly electrophilic phosphorus-based Lewis acid catalysts  

Pyridinium–phosphonium dications: highly electrophilic phosphorus-based Lewis acid catalysts

Julia M. Bayne, Michael H. Holthausen a and Douglas W. Stephan

Using commercially available 2-pyridyldiphenylphosphine (o-NC5H4)PPh2, a family of electrophilic phosphonium cations [(o-NC5H4)PFPh2]+ (2) and dications [(o-MeNC5H4)PRPh2]2+(R = F (4); Me (5)) were prepared. The Lewis acidity of these pyridinium–phosphonium dications was probed in Friedel–Crafts dimerization, hydrodefluorination, hydrosilylation, dehydrocoupling and hydrodeoxygenation reactions.

Date: 2016-04-14

Phosphorus Lewis acids: emerging reactivity and applications in catalysis  

Phosphorus Lewis acids: emerging reactivity and applications in catalysis

J. M. Bayne and D. W. Stephan

Part of the renaissance in main group chemistry has been a result of the focus on reactivity and catalysis. In this tutorial review, we focus attention on the role of phosphorus-based Lewis acids in such advances.

Date: 2016-03-09

Cationic Silicon Nanocrystals with Colloidal Stability  

Cationic Silicon Nanocrystals with Colloidal Stability

Kenneth K. Chen, Kristine Liao, Gilberto Casillas, Yiying Li, and Geoffrey A. Ozin

In this report, for the first time the synthesis of a novel class of cationic quaternary ammonium-surface-functionalized silicon nanocrystals (ncSi) using a novel and highly versatile terminal alkyl halide-surface-functionalized ncSi synthon is described. The distinctive features of these cationic ncSi include colloidal stability, pH-independent positive surface charge, and size-tunable photoluminescence in the biologically relevant near-infrared-to-red spectral region. These cationic ncSi are characterized via a combination of high-resolution scanning transmission electron microscopy with energy-dispersive X-ray analysis, Fourier transform infrared, X-ray photoelectron, and photoluminescence spectroscopies, and zeta potential measurements.

Date: 2016-02-23

Optimizing photo-control of bZIP coiled-coils by azobenzene  

Optimizing photo-control of bZIP coiled-coils by azobenzene

Ahmed Ali; Matthew Forbes; Andrew Woolley has now been published

The cover picture shows a photoswitchable azobenzene cross-linked peptide (red) that acts as a dominant negative inhibitor of DNA binding by the transcription factor CREB (green). The DNA target is shown in white. G. A. Woolley and co-workers show that the largest degree of conformational control is obtained when the photoswitchable cross-linker is placed at the site of highest intrinsic helical propensity in the inhibitor.

Date: 2015-09-03

 

Doug Stephan

Published in Chem. Bull. Soc Jap., this invited review by Weicker and Stephan, describes FLP chemistry that has been developed employing Lewis acids derived from group 13, 14, and 15 based systems.

Date: 2015-08-21

 



Novel boron-containing 1,2,4-amphoteric molecules, described by Andrei K. Yudin and co-workers (Click this link), were used to generate a broad collection of borylated heterocycles with uncommon positioning of the carbon-boron bonds. The cover art compares this research to flowers blossoming during spring. If the boron-containing heterocycles were likened to flowers, the newly developed molecules would be the sprouts of this new approach. The growth of the young shoots through the soil is compared to the production of 1,4-dicarbonyl boronate intermediates upon photoredox-mediated “germination”. The 1,4-dicarbonyl motifs undergo condensation reactions with a range of nucleophiles, “blossoming” into heterocycles of medicinal significance.

Date: 2015-07-31

A Highly-Ordered 3D Covalent Fullerene Framework  

A Highly-Ordered 3D Covalent Fullerene Framework

Norma K. Minar, Dr. Kun Hou, Christian Westermeier, Dr. Markus Döblinger, Dr. Jörg Schuster, Fabian C. Hanusch, Dr. Bert Nickel, Prof. Dr. Geoffrey A. Ozin and Prof. Dr. Thomas Bein

Article first published online: 10 JUN 2015 | DOI: 10.1002/anie.201504744


A 3D covalent fullerene framework with a structure based on hexa-functionalized fullerene building blocks with octahedral symmetry is reported by Thomas Bein, Geoffrey Ozin and coworkers in their Communication (DOI: 10.1002/anie.201411344). Each fullerene in the highly ordered framework is separated from the next by six functional groups and the mesoporosity is controlled by template-directed, evaporation-induced self-assembly with a block copolymer. The TEM images in the background show the periodic porous fullerene framework.

Date: 2015-06-15

Activation of Ultrathin Films of
Hematite for Photoelectrochemical
Water Splitting via H<sub>2</sub> Treatment  

Activation of Ultrathin Films of Hematite for Photoelectrochemical Water Splitting via H2 Treatment

J. Moir, N. Soheilnia, K. Liao, P. O’Brien, Y. Tian, K. S. Burch, G. A. Ozin*

The Inside Back cover picture shows ultrathin films of α-Fe2O3 before and after treatment in 5% H2 in Ar at 450°C. The hydrogen treatment creates oxygen vacancies in the iron oxide lattice, resulting in a non-stoichiometric hematite phase that is active for photoelectrochemical water oxidation. Electrochemical impedance spectroscopy reveals the buildup of a surface state capacitance that is only present for the hydrogen treated films when under illumination, at the point of photocurrent onset. A concomitant decrease in charge trapping resistance suggests that this is due to a build-up of photogenerated holes at the surface of the H2-treated films, which allows the water oxidation reaction to proceed. More details can be found in the Full Paper by Moir et al.
(DOI: 10.1002/cssc.201402945).

Date: 2015-05-21

 

Dwight Seferos

Heavy atom substitution is a promising strategy for the development of high performance materials for organic electronic applications. In particular, the use of tellurium in place of selenium or sulfur in conjugated polymers lends new properties to these materials such as red-shifted optical absorption, high polarizability, high dielectric constant, and strong intermolecular interactions. These properties are favorable for polymer electronics. The use of polymers containing tellurophene, the tellurium analogue of the well-studied thiophene, has only recently begun to emerge in the literature. In this Perspective we discuss the current status of tellurium-containing polymers in terms of their synthesis, properties, and performance, and suggest future directions for the field towards obtaining high-performance materials.

Date: 2015-02-18

 

Sarvothaman, M.K.; Kim, K.S.; Seale, B.; Brodersen, P.M.; Walker, G.C.; Wheeler, A.R.

Non-specific adsorption of biomolecules (or “biofouling”) is a major problem in microfluidics and many other applications. The problem is particularly pernicious in digital microfluidics (DMF, a technique in which droplets are manipulated electrodynamically on an array of electrodes coated with a hydrophobic insulator), as local increases in surface energy that arise from fouling can cause droplet movement to fail. We report a new solution to this problem: a device coating bearing a combination of fluorinated poly(ethylene glycol) functionalities (FPEG) and perfluorinated methacrylate (FA) moieties. A range of different FPEG-FA copolymers were synthesized containing varying amounts of FPEG relative to the fluorinated backbone. Coatings with low %FPEG were found to result in significant reductions in protein adsorption and improvements in device lifetime (up to 5.5-fold) relative to the state of the art. An analysis of surface topology and chemistry suggests that FPEGFA surfaces undergo a dynamic reconstruction upon activation by applying DMF driving potentials, with FPEG groups forming vertical protrusions out of the plane of the device surface. An analysis of changes in surface wettability and adhesion as a function of activation supports this hypothesis. This innovation represents an advance for digital microfluidics, and may also find use in other applications that are currently limited by biofouling.

Date: 2015-02-12

 

Douglas Stephan

Sulfur monoxide bears similarities to molecular oxygen, but unlike O2, SO is unstable on Earth and is only found in outer space. In their Communication (DOI: 10.1002/anie.201409969), L. Longobardi and D. Stephan show that P/B frustrated Lewis pairs react with an N-sulfinylamine to form PNSOB linkages. These species can be regarded as phosphinimine–borane-stabilized sulfur monoxide complexes and they act as sources of SO, effecting the oxidation of PPh3 and delivering SO to various acceptors.

Date: 2015-02-04

 

Elisa I. Carrera and Dwight S. Seferos

Carrera et al. report that visible light induces the efficient photoreductive elimination of bromine, chlorine, and for the first time, fluorine from the tellurium center of 2,5-diphenyltellurophene. Dalton Trans., 2015, 44, 2092-2096.

Date: 2015-01-28

Exploring the Possibilities and Limitations of a Nanomaterials Genome  

Exploring the Possibilities and Limitations of a Nanomaterials Genome

Chenxi Qian, Todd Siler and Geoffrey A. Ozin

The graphic art shows a Word Cloud depiction of the Nano World which considers how the whole human brain creates, stores and transforms concepts of Nanochemistry, assembling concepts of the Nanomaterials Genome in new ways and to useful products. As implied by this image, the letter size in the right brain reflects the frequency of the top 200-400 words presented in this Concept article in Small. Imagine merging these words and the associative images they evoke as cerebral hemispheric specializations are integrated enabling the realization of our intuitions, inventions and innovations. Word Cloud software has been created by wordle.net © IBM Corporation and Jonathan Feinberg. The rapid development of nanomaterials science and technology nowadays calls for a multifunctional data system, namely the Nanomaterials Genome. It is designed for intelligent and convenient categorizing, organizing, sifting, sorting, and integrating pertinent information about the known nanomaterials, and utilizing this information to explore the unknown in scientifically and technologically innovative ways, ultimately to benefit society. Inspired by work on the Human Genome project, which began in 1989 together with motivation from the recent emergence of the Materials Genome project initiated in 2011 and the Nanoinformatics Roadmap 2020 instigated in 2010, we envision the development of a Nanomaterials Genome (NMG) database and possible peripherals with the most advanced data-mining tools that leverage inference engines to help create, connect and interpret patterns of nanomaterials information. The NMG would enable the realization of our intuitions, inventions and innovations to be applied to the development of next generation energy materials for solar cells, fuel cells, batteries and supercapacitors and biomedical materials for diagnostics, therapeutics and imaging, organ, skin and bone replacement and repair.

Date: 2015-01-20

 

Laura B. Hoch, Thomas E. Wood, Paul G. O'Brien, Kristine Liao, Laura M. Reyes, Charles A. Mims and Geoffrey A. Ozin

Two advances towards the vision of the “solar fuels refinery” of the future are portrayed in the front cover art that encapsulates the essence of two papers published in the new elite Wiley-VCH journal Advanced Science entitled “The Rational Design of a Single-Component Photocatalyst for Gas-Phase CO2 Reduction Using Both UV and Visible Light” published by Laura B. Hoch, Thomas E. Wood, Paul G. O'Brien, Kristine Liao, Laura M. Reyes, Charles A. Mims and Geoffrey A. Ozin, in Advanced Science 2014, 1: Article first published online: 29 DEC 2014 | DOI: 10.1002/advs.201470001 and “Photomethanation of Gaseous CO2 over Ru/Silicon Nanowire Catalysts with Visible and Near-Infrared Photons” by Paul G. O'Brien, Amit Sandhel, Thomas E. Wood, Abdinoor A. Jelle, Laura B. Hoch, Doug D. Perovic, Charles A. Mims and Geoffrey A. Ozin, in Advanced Science, 2014, 1: Article first published online: 25 NOV 2014 | DOI: 10.1002/advs.201400001. The cover art, courtesy of Chenxi Qian, illustrates the concept of how “black holes” for photons, phonons, excitons and molecules, in two new classes of nanostructure, allow light-assisted, gas-phase heterogeneous catalytic CO2 reduction to CO or CH4. The ultimate goal of this research is to facilitate an energy transition from today’s unsustainable “fossil fuel economy” of burn-and-adapt to greenhouse gas climate change to a new and sustainable “carbon dioxide economy”, where greenhouse gas emissions are utilized as a chemical feed stock rather than being treated as a waste product.

Date: 2015-01-05

Nanobiosensors and Nanobioanalyses  

Nanobiosensors and Nanobioanalyses

Mun'delanji C. Vestergaard, Kagan Kerman, I-Ming Hsing, Eiichi Tamiya (Eds.)

Nanomaterials have become an essential part of biosensors and bioanalyses in the detection and monitoring of medical, pharmaceutical, and environmental conditions, from cancer to chemical warfare agents. This book, with its distinguished editors and international team of expert contributors, will be an essential guide for all those involved in the research, design, development, and application of nanomaterials in biosensors and bioanalyses.

Date: 2014-10-31

 

Geoffrey Ozin

The cover picture illustrates the performance of Nb3O7(OH), a new hydrogen evolution catalyst: Under solar illumination photo-generated holes are scavenged by methanol while the reduction of protons to hydrogen is kinetically hindered. Thus the electrons remain in the conduction band and/or trap states turning the photocatalyst deep blue. The deposition of metal particles on the surface introduces a new reaction side, which now is able to overcome the kinetic barrier. Subsequently hydrogen is formed and no photochromic process is observed.

Date: 2014-08-14

 

Andrew P. Dicks, Landon J. G. Edgar, Katherine J. Koroluk and Mehrnaz Golmakani

In “Green Chemistry Decision-Making in an Upper-Level Undergraduate Organic Laboratory”, a self-directed, independent synthesis experiment for a third-year undergraduate organic laboratory (CHM 343H) is described. Students are provided with the CAS numbers of starting and target compounds and devise a synthetic plan to be executed over two, 4.5 h laboratory periods. They consult the primary literature to develop and carry out an azlactone synthesis and analysis, incorporating green chemistry principles and techniques without detailed guidance from course instructors. This well-received laboratory requires students to plan, make independent decisions, and apply their knowledge and understanding of green chemistry.

Date: 2014-07-23

 

D. W. Stephan and C. Pranckevicius

In a Communication by D. W. Stephan and C. Pranckevicius, an abnormally bound, anionic N-heterocyclic carbene (NHC) is transmetalated to ruthenium affording rare examples of anionic NHCs on ruthenium, that bind to the abnormal position of the carbene or in an unprecedented binding of the carbene via the methine position of the IDipp-BF3 ligand.

Date: 2014-05-27

 

Douglas Stephan

Ru-η6-arene complexes were investigated as Lewis acids. These species form Lewis acid-base adducts via coordination of the base to the ortho or para- carbons of the η6-arene ring as well as at the B center depending on the nature of the base. In addition these species also form frustrated Lewis pairs (FLPs) with with sterically demanding donors. In some cases, these FLPs can effect H2 activation with hydride delivery to the ortho-position of the coordinated ring.

Date: 2014-04-07

Copolymerization of Metal Nanoparticles: A Route to Colloidal Plasmonic Copolymers  

Copolymerization of Metal Nanoparticles: A Route to Colloidal Plasmonic Copolymers

Liu, K.; Lukach, A.; Sugikawa, K.; Chung, L.; Vickery, J.; Therien-Aubin, H.; Yang, B.; Rubinstein, M.; Kumacheva, E. Copolymerization of Metal Nanoparticles: A Route to Colloidal Plasmonic Copolymers Angew. Chem. Intnl. Ed. 53, 2648-2653 (2014).

The self-assembly of colloidal analogues of molecular copolymers can greatly benefit fundamental studies of molecular copolymerization and nanotechnology. In their Communication E. Kumacheva, et al. present microscopy and spectroscopy analyses to develop design rules and a kinetic model for the growth of colloidal random and block copolymers made from plasmonic nanorods with different lengths and compositions.

Date: 2014-03-05

LED-based interferometric reflectance imaging sensor for the detection of amyloid-beta aggregation  

LED-based interferometric reflectance imaging sensor for the detection of amyloid-beta aggregation

Xin R. Cheng, George G. Daaboul, Selim Unlu and Kagan Kerman

Self-aggregation of amyloid-beta (Abeta) plays an important role in the pathogenesis of Alzheimer's disease (AD). Small molecule inhibitors of Abeta fibril formation reduce the Abeta-mediated neurotocixity. In this report, the interaction of Abeta with well-described modulators, (-)epigallocatechin-3-gallate (EGCG) and Zn(II), was detected using an LED-based interferometric reflectance imaging sensor (LED-IRIS) in a high-throughput and real-time format. The proof-of-concept study reported here introduces a novel platform to facilitate the screening of small molecules towards the discovery of promising AD therapeutics, Analyst, 2014, 139, 59-65

Date: 2014-01-20

 

Choi, K.; Ng, A.H.C.; Fobel, R.; Chang-Yen, D.A.; Yarnell, L.E.; Pearson, E.L.; Oleksak, C.M.; Fischer, A.T.; Luoma, R.P.; Robinson, J.M.; Audet, J.; Wheeler, A.R.

"Automated Digital Microfluidic Platform for Magnetic-Particle-Based Immunoassays with Optimization by Design of Experiments" Anal. Chem. 2013, 85, 9638-9646.

Date: 2013-10-17

 

Sean Liew and Andrei K. Yudin

Aziridine aldehyde dimers participate in a syn¬-selective Petasis borono-Mannich reaction to furnish aziridine-containing diamine building blocks, which can be regioselectively ring-opened to generate highly substituted chiral diamine scaffolds. This chemistry is likened to the colors on a painter’s palette, where mixing of the primary components can generate a plethora of vibrant colors.

Date: 2013-12-09

Ketenes and other Cumulenes as Reactive Intermediates  

Ketenes and other Cumulenes as Reactive Intermediates

Annette D. Allen, Thomas T. Tidwell

Cumulenes are a highly varied class of compounds, including such species as ketenes, allenes, ketenimines, and isocyanates, as well as analogues where carbon is replaced by silicon or germanium, oxygen is replaced by sulfur or selenium, and nitrogen by phosphorus or arsenic. The distinctive bonding pattern of cumulenes consists of a central sp hybridized atom with double bonds to two other sp or sp2 hybridized atoms.

Date: 2013-10-03

Can We Model Snow Photochemistry? Problems with the Current Approaches  

Can We Model Snow Photochemistry? Problems with the Current Approaches

Florent Domine, Josué Bock, Didier Voisin, James Donaldson

Snow and the impurities contained therein form a complex multiphase photochemical reactor, releasing reactive molecules to the atmosphere and dramatically impacting the composition and reactivity of the lower polar troposphere. Challenges in our understanding and modeling abilities of this complex natural system are discussed.

Date: 2013-07-03

Biological Activity of sym-Triazines with Acetylcholine-like Substitutions as Multitarget Modulators of Alzheimer's Disease  

Biological Activity of sym-Triazines with Acetylcholine-like Substitutions as Multitarget Modulators of Alzheimer's Disease

Veloso AJ, Chow AM, Dhar D, Tang DW, Ganesh HV, Mikhaylichenko S, Brown IR, Kerman K

Two novel sym-triazine derivatives were demonstrated as promising candidates against Alzheimer’s disease, supported by their capabilities in modulation of amyloid-β (Aβ1-42) fibril formation and inhibition of acetylcholinesterase activity. The cover figure shows that these sym-triazine derivatives were well tolerated and have potential beneficial effects on human neurons, promoting differentiation and extension of neurite processes, as highlighted with the cytoskeleton marker protein α-tubulin (green), and upregulating expression of the synaptic marker protein synaptophysin (red, indicated by white box). Art designers: Ari M. Chow and Anthony J. Veloso.

Date: 2013-06-24

 

Bernie Kraatz

Upon irradiation zinc porphyrin modified nanostructured silver surfaces gives rise to strong photocurrents that are influenced by nucleoside interactions with the phorphyrin.

Date: 2013-05-29

 

G. Erker and D.W. Stephan

G. Erker and D.W. Stephan have edited two volumes for the Topics in Current Chemistry Series on “Frustrated Lewis Pairs” These volumes contain over 20 chapters from researchers around the world working on FLP chemistry and describe the state-of-the-art in this rapidly growing area of inorganic/organometallic/organic chemistry.

Date: 2013-04-19

 

Geoffrey Ozin

The Canadian Journal of Chemistry has published a special Festschrift issue dedicated to Professor Geoffrey Ozin on the occasion of his 70th birthday. The issue contains several articles from group alumni and a tribute to Geoff by Professor George Whitesides from Harvard. The full issue is available at, http://www.nrcresearchpress.com/toc/cjc/90/12.

Date: 2013-03-22

 

Michael J. Sgro and Douglas W. Stephan

Sgro and Stephan have showed Hf-phosphinoamide cation complexes behave as metal-based frustrated Lewis pairs and bind one or two equivalent of CO2 and in as well can activate CO2 in a bimetallic fashion to give a pseudo-tetrahedral P2CO2 fragment linking two Hf centers.

Date: 2013-03-13

Surface Aligned Reaction (SAR)  

Surface Aligned Reaction (SAR)

Zhanyu Ning and John C. Polanyi, J. Chem. Phys. 137, 091706 (2012)

This cover picture shows a computed sequence of events as a chlorine atom (green) recoils from a surface-aligned electronically-excited chlorobenzene molecule, picking up a hydrogen atom (white) from an adjacent co-adsorbed hydrogen iodide molecule (iodine atom in red). This exemplifies a novel procedure for controlling the motions of atoms in reaction; ‘Surface Aligned Reaction’.

Date: 2013-02-28

Pulsed-Dosing Controls Self-Assembly:  1-Bromopentane on Si(111)-7×7  

Pulsed-Dosing Controls Self-Assembly: 1-Bromopentane on Si(111)-7×7

Alon Eisenstein, K.R. Harikumar, Kai Huang, Iain R. McNab, John C. Polanyi, Amir Zabet-Khosousi

The cover picture shows a pair of Scanning Tunneling Microscope images of 1-bromopentane on silicon with markedly different patterns of physisorption, depending on the rate of deposition controlled by a novel pulsed-dosing system that ejects molecules into ultra-high vacuum.

Date: 2013-02-21

Spin of a Nanotech Spin-Off  

Spin of a Nanotech Spin-Off

Geoffrey A. Ozin

Innovation in advanced technology often springs from ideas birthed in universities yet the attitudes of professors and their students towards entrepreneurship and their stance on the collision between fundamental research in the pursuit of knowledge and applied research directed to the creation of intellectual property, inventions, companies, jobs, products, and wealth, is not that well appreciated either inside or outside our universities. In this article I will explore this interesting issue and try to gain some insight into the challenges faced by professors confronted by the challenge of transforming basic science and engineering knowledge into products in the market place, using nanotechnology as a case study. While the specific focus of this article is on nanotechnology, more generic issues are also raised that relate to transformational business development and entrepreneurship in society and universities in a larger sense.

Date: 2013-02-06

 

Doug Stephan

A sterically unencumbered aniline base can be transformed into a bulky Lewis base by converting it into a [2]rotaxane. This Lewis base donor, which is surrounded by a protective macrocyclic ring, exhibits the reactivity of a frustrated Lewis pair (e.g. activation of H2(g)) without the need for direct covalent modification to increase its bulk.

Date: 2013-01-28

Boranes and Borohydrides  

Boranes and Borohydrides

Doug Stephan

Stephan et al published papers on the FLP chemistry of phosphinimines and boranes, as well as a paper on diazomethane insertions into electrophilic boranes for use in FLP chemistry.

Date: 2013-01-21

Silicon Nanocrystal OLEDs: Effect of Organic Capping Group on Performance  

Silicon Nanocrystal OLEDs: Effect of Organic Capping Group on Performance

Melanie L. Mastronardi , Eric J. Henderson , Daniel P. Puzzo , Yilu Chang , Zhi Bin Wang , Michael G. Helander , Junho Jeong , Nazir P. Kherani , Zhenghong Lu , and Geoffrey A. Ozin

The synthesis of highly luminescent, colloidally-stable and organically-capped silicon nanocrystals (ncSi) and their incorporation into a visible wavelength organic light-emitting diode (OLED) is reported. By substituting decyl chains with aromatic allylbenzene capping ligands and size-selecting visible emitting ncSi, superior packing density, enhanced charge transport, and an improved photoluminescence absolute quantum yield of the ncSi is obtained in the active layer of an OLED.

Date:

Heterolytic Activation of H2 Using a Mechanically Interlocked Molecule as a Frustrated Lewis Base  

Heterolytic Activation of H2 Using a Mechanically Interlocked Molecule as a Frustrated Lewis Base

Christopher B. Caputo, Kelong Zhu, V. Nicholas Vukotic, Stephen J. Loeb, Douglas W. Stephan

The reactivity of frustrated Lewis pairs is induced by the utilization of a sterically unencumbered aniline as the axle in a [2]rotaxane. In their Communication (DOI: 10.1002/anie.201207783), S. J. Loeb, D. W. Stephan, and co-workers show, that the [2]rotaxane imparts enough steric bulk to the base to preclude adduct formation with B(C6F5)3. This unique modification also shows frustrated Lewis pair reactivity in the activation of H2 at room temperature.

Date: 2012-12-12

Silicon Nanocrystals: Small Silicon, Big Opportunities: The Development and Future of Colloidally-Stable Monodisperse Silicon Nanocrystals  

Silicon Nanocrystals: Small Silicon, Big Opportunities: The Development and Future of Colloidally-Stable Monodisperse Silicon Nanocrystals

Melanie L. Mastronardi, Eric J. Henderson, Daniel P. Puzzo, Geoffrey A. Ozin, Advanced Materials, 2012, 24, 5775

Small silicon, big opportunities: A colloidally-stable silicon nanocrystal (ncSi) polydispersion size-separated into monodisperse fractions exhibits photoluminescence blue-shifting with decreasing particle size under photoexcitation. The ability to prepare ncSi monodispersions opens the door to access and study tunable size-dependent properties that promise to have a huge impact on the development of silicon nanomaterials and technology. Recent contributions in size-separation methods, characterization of size-dependent property trends, and ncSi applications are discussed.

Date: 2012-11-09

Versatile Strategy for Biochemical, Electrochemical and Immunoarray Detection of Protein Phosphorylations  

Versatile Strategy for Biochemical, Electrochemical and Immunoarray Detection of Protein Phosphorylations

S. Martic, M. Gabriel, J. P. Turowec, D. W. Litchfield, H.-B. Kraatz

Protein kinases can use ferrocene-ATP conjugates to transfer the redox active ferrocene group to protein and peptide targets. Ferrocene transfer can be quantified electrochemically with the help of an antiferrocene antibody.

Date: 2012-10-23

Introduction to the Focus Issue on Marine Boundary Layer: Ocean Atmosphere Interactions Processes  

Introduction to the Focus Issue on Marine Boundary Layer: Ocean Atmosphere Interactions Processes

D. J. Donaldson and Christian George

The exchange of matter and energy between the sea surface and the atmosphere is a critical controller of the climate on Earth. This special issue on marine boundary layer processes contains several articles relating to the transport and reactions of chemical compounds at the air-sea boundary, and how such transformations influence the atmosphere in the overlying marine boundary layer.

Date: 2012-10-02

Label-free methods for probing the interaction of clioquinol with amyloid-β  

Label-free methods for probing the interaction of clioquinol with amyloid-β

Xin Ran Cheng, Vinci Wing Sze Hung, Simona Scarano, Marco Mascini, Maria Minunni and Kagan Kerman

Kerman’s team and his Italian collaborators have developed label-free methods based on surface plasmon resonance (SPR) and thickness shear mode acoustic wave sensors (TSM-AWS) to detect the interaction between amyloid-β and clioquinol in real-time.

Date: 2012-08-03

 

Joel A. Drewry , Steven Burger , Amir Mazouchi , Eugenia Duodu , Paul Ayers , Claudiu C. Gradinaru and Patrick Gunning

Gunning et al. discuss the synthesis and evaluation of a novel class of ditopic coordination complex-based SH2 domain mimetics using de novo rational and computational design. Lead compounds bind with selectivity to target phosphopeptides via the same two-site binding mode employed by SH2 domains in a cell.

Date: 2012-07-05

Reversible formal insertion of CO2 into a remote C-H bond of a ligand in a Ru(II) complex at room temperature  

Reversible formal insertion of CO2 into a remote C-H bond of a ligand in a Ru(II) complex at room temperature

Vincent T. Annibale and Datong Song

This reversible transformation of CO2 features an actor ligand and a spectator metal centre. The forward and backward reactions both occur spontaneously at room temperature, which is related to important processes in nature that mediate the uptake and release of CO2 under ambient conditions.

Date: 2012-05-10

Dried Blood Spot Analysis by Digital Microfluidics Coupled to Nanoelectrospray Ionization Mass Spectrometry  

Dried Blood Spot Analysis by Digital Microfluidics Coupled to Nanoelectrospray Ionization Mass Spectrometry

Steve C. C. Shih, Hao Yang, Mais J. Jebrail, Ryan Fobel, Nathan McIntosh, Osama Y. Al-Dirbashi, Pranesh Chakraborty, and Aaron R. Wheeler

Shih et al. developed a new method to couple digital microfluidics to nanoelectrospray ionization mass spectrometry. The system was applied to analyzing dried blood spot (DBS) samples from newborn patients to quantify disease markers. Because this method facilitates analysis with minimal manual intervention, there is great enthusiasm for applying similar techniques to the growing number of applications adopting the DBS sample format for analysis.

Date: 2012-04-24

 

Paul Brumer

This text provides a systematic introduction to the fundamental principles of coherent control and to the underlying physics and chemistry. The book covers the latest techniques and applications, including bimolecular collisions, effects of decoherence, developments in nanostructures, attosecond processes, optical control of chirality and strong field quantum control. Recent results and ongoing challenges in the field are emphasized throughout.

Date: 2012-03-21

Chloro- and phenoxy-phosphines in frustrated Lewis pair additions to alkynes  

Chloro- and phenoxy-phosphines in frustrated Lewis pair additions to alkynes

Christopher B. Caputo, Stephen J. Geier , Eva Y. Ouyang, Christoph Kreitner and Douglas W. Stephan

The range of phosphines capable of FLP additions to alkyne in conjunction with the Lewis acid B(C6F5)3 is extended in this study, thus broadening the "FLP game".

Date: 2012-02-01

Glancing-angle Raman study of nitrate and nitric acid at the air–aqueous interface  

Glancing-angle Raman study of nitrate and nitric acid at the air–aqueous interface

Sumi N. Wren, D.J. Donaldson
Chemical Physics Letters 522 (2012) 1–10


Glancing-angle Raman spectra of aqueous KNO3 and HNO3 solutions were measured to determine the degree of nitric acid dissociation in the bulk and in the surface region. Acid dissociation in the surface region is similar to that in the bulk and depends strongly on water molecule availability to the dissociation process. The spectra were used to construct an adsorption isotherm for nitrate anion at the water surface; it exhibits an almost neutral surface affinity.

Date: 2012-01-09

Single Step Solution Phase Synthesis of Water Soluble Colloidally Stable Carbon Quantum Dots - Sensitizers for Nanocrystalline Titania Solar Cells  

Single Step Solution Phase Synthesis of Water Soluble Colloidally Stable Carbon Quantum Dots - Sensitizers for Nanocrystalline Titania Solar Cells

Peter Mirtchev, Eric J. Henderson, Navid Soheilnia, Christopher M. Yip and Geoffrey A. Ozin

Carbon quantum dots (CQD's) have recently emerged as viable alternatives to traditional semiconductor quantum dots because of their facile and low cost synthesis, long term colloidal stability, size tuneable visible to near infrared wavelength bright photoluminescence, and low environmental and biological toxicity. The compatible surface chemistry, good solubility in polar solvents and extensive optical absorption throughout the visible and near infrared wavelength regions render CQD's as potentially useful sensitizers for photovoltaic applications. Presented herein are a new single step solution phase synthesis of water-soluble, colloidally stable CQD's and a preliminary exploration of their utilization as sensitizers in nanocrystalline TiO2-based solar cells. With size and surface control CQD's could potentially match currently used inorganic and organic dyes.

Date: 2012-01-04

Hierarchical Nanoparticle Bragg Mirrors: Tandem and Gradient Architectures  

Hierarchical Nanoparticle Bragg Mirrors: Tandem and Gradient Architectures

Engelbert Redel, Chen Huai, Michael Renner, Georg von Freymann, Geoffrey A. Ozin, Small, 2011, 7, 3465-3471

The cover picture shows a new kind of broadband optical reflector made by bottom-up self-assembly of nanoparticle metal-oxide multilayers fashioned as hierarchical nanoporous tandem and gradient Bragg mirrors. The optical properties of this genre of Bragg mirror can be passively tuned through variations of the composition of the nanoparticle metal-oxide layers and actively tuned through reversible adsorption–desorption of different molecular species in the nanopores, thereby providing myriad opportunities for the management of light in solar cells, photocatalysts, and photonic nose sensors in novel ways.

Date: 2011-12-14

Identification of a non-phosphorylated, cell permeable, small molecule ligand for the Stat3 SH2 domain  

Identification of a non-phosphorylated, cell permeable, small molecule ligand for the Stat3 SH2 domain

Patrick Gunning

Bioorganic & Medicinal Chemistry Letters, Volume 21, Issue 18, 15 September 2011, Pages 5605-5609

Signal transducer and activator of transcription 3 (Stat3) protein is a cytosolic transcription factor that is aberrantly activated in numerous human cancers. Inhibitors of activated Stat3?Stat3 protein complexes have been shown to hold therapeutic promise for the treatment of human cancers harboring activated Stat3. Herein, we report the design and synthesis of a focused library of salicylic acid containing Stat3 SH2 domain binders.



Date: 2011-12-14

 

Shunthirasingham, C., T. Gouin, Y.D. Lei, C. Ruepert, L.E. Castillo, F. Wania

Current use pesticide transport to Costa Rica's high altitude tropical cloud forest.

Environ. Toxicol. Chem. 2011, 30, 2709-2717.

DOI: 10.1002/etc.671

Date: 2011-12-14

 

Mann, E., T. Meyer, C.P.J. Mitchell, F. Wania

Mercury fate in ageing and melting snow: Development and testing of a controlled laboratory system J. Environ. Monit. 2011, 2011, 13, 2695-2702.
*DOI: *10.1039/C1EM10297D

Date: 2011-11-30

 

Mohtashim H. Shamsi and Heinz-Bernhard Kraatz

It describes the electrochemical identification of artificial oligonucleotides related to bovine species by scanning electrochemical microscopy and serves as an example for the identification of species based on mismatches in the mitochondrial cytochrome C1 oxidase gene.

Date: 2011-11-18

Polyselenophenes with Distinct Crystallization Properties  

Polyselenophenes with Distinct Crystallization Properties

Dwight Seferos's group

The polythiophene derivative poly(3-hexyl)thiophene (P3HT) has become one of the most well studied organic materials due to its interesting and important chemical and physical properties. Two different crystal structures have been observed for P3HT, type-1 and type-2, however a pure type-2 structure has never been obtained. Herein, we investigate the crystal structure of polyselenophene analogs (P3HS), and discover that a pure type-2 phase is formed in low molecular weight P3HS (Mn = 5.9 kg/mol). Wide-angle X-ray scattering shows that the type-2 phase is readily formed and stable at room temperature, which is very distinct from what is observed in control experiments with P3HT. Absorption spectra of P3HS films with the pure type-2 phase lack the typical shoulder peaks indicating that ?-? stacking is relatively poor in the type-2 phase. Scanning transmission electron microscopy (STEM) images, however, show that large nanofibers are formed by type-2 crystallization thereby demonstrating the potential of P3HS to drive unique types of self-assembled structures through crystallization, and should motivate continued efforts on selenophene analogs of P3HT for a variety of studies and uses.

Date: 2011-11-14

 

Shunthirasingham, C., C.E. Oyiliagu, X.S. Cao, T. Gouin, F. Wania, S.-C. Lee, K. Pozo, T. Harner, D.C.G. Muir

Spatial and temporal pattern of pesticides in the global atmosphere J. Environ. Monitor. 2010, 12, 1650-1657.
DOI:10.1039/C0EM00134A.

Date: 2011-11-02

Interfacial behavior of immortalized hypothalamic mouse neurons detected by acoustic wave propagation  

Interfacial behavior of immortalized hypothalamic mouse neurons detected by acoustic wave propagation

Shilin Cheung, Laura J. Fick, Denise D. Belsham, David A. Lovejoy and Michael Thompson Analyst, 2011, 136, 4412-4421

A transverse acoustic wave sensor was used to detect the cellular changes associated with the deposition, adhesion, proliferation, and cytoskeletal disruptions in immortalized hypothalamic mouse neurons.

Date: 2011-10-18

 

Molly Shoichet

The Shoichet Lab demonstrates that multiple proteins can be spatially immobilized simultaneously in defined 3D volumes to guide cell growth and fate.

Date: 2011-10-14

Optical trapping for the characterization of amyloid-beta aggregation kinetics  

Optical trapping for the characterization of amyloid-beta aggregation kinetics

Anthony J. Veloso, Hiroyuki Yoshikawa, Xin R. Cheng, Eiichi Tamiya and Kagan Kerman

Alzheimer’s disease (AD) is marked by the accumulation of neuronal plaques from insoluble amyloid- beta (Ab) peptides. Growing evidence for the role of Ab oligomers in neuronal cell cytotoxicity and pathogenesis has prompted the development of novel techniques to better understand the early stages of aggregation. K. Kerman and co-workers applied near infrared (NIR) optical trapping technique to characterize the early stages of Ab aggregation in the presence of a beta-sheet intercalating dye, Congo Red (CR), as the fluorescent marker. The integration of fluorescence analysis with NIR optical trapping has provided a new outlook into the first two hours of Ab aggregation.

Date: 2011-09-30

 

Wong, F., F. Wania

Visualising the equilibrium distribution and mobility of organic contaminants in soil using the chemical partitioning space J. Environ. Monit. 2011, 13, 1569-1578. DOI: 10.1039/C1EM10109A

Date: 2011-09-19

A digital Microfluidic Method For Dried Blood Spot Analysis  

A digital Microfluidic Method For Dried Blood Spot Analysis

Mais J. Jebrail, Hao Yang, Jared M. Mudrik, Nelson M. Lafreničre, Christine McRoberts, Osama Y. Al-Dirbashi, Lawrence Fisher, Pranesh Chakraborty and Aaron R. Wheeler

Aaron R. Wheeler and coworkers, have developed two digital microfluidic methods that could make analyzing dried blood spots more convenient. In digital microfluidics, discrete droplets of sample and reagents are manipulated and analyzed on an open surface by applying electrical potentials to an underlying array of electrodes. The methods are fast, robust, precise, and compatible with automation.

Date: 2011-09-07

High-throughput Combinatorial Cell Co-culture using Microfluidics  

High-throughput Combinatorial Cell Co-culture using Microfluidics

Ethan Tumarkin, Eugenia Kumacheva

This paper reports a microfluidic approach to the fast throughput generation of microenvironments for cell co-culture. The strategy provides a new operational platform for the co-encapsulation of a controlled number of cells of different lineages in well-defined microgel environments. The microfluidic approach enables understanding of how stem cell fate is affected by their interactions in microenvironments.

Date: 2011-07-14

Polytellurophenes  

Polytellurophenes

Ashlee Jahnke, Dwight Seferos

Polytellurophenes are a virtually unexplored class of conjugated polymer. In this work the synthetic methodologies that have been used to prepare polytellurophenes are chronicled. The properties of the resulting polymers are discussed and their potential for use as electronic materials is evaluated. It is far too early to know if these materials will lead to a useful class of thin-film semiconductors, however some key challenges associated with their synthesis and implementation are outlined. These challenges will need to be addressed as the conjugated polymer research community begins to utilize this area of the periodic table.

Date: 2011-06-27

Microfluidic Reactors for Polymer Particles  

Microfluidic Reactors for Polymer Particles

Eugenia Kumacheva, Piotr Garstecki

Continuous microfluidic synthesis of particulate materials is rapidly gaining momentum. Unprecedented control over particle composition, size, shape and morphology achieved by the hydrodynamic means paves the way for producing high-value materials with advanced properties. The book authored by Eugenia Kumacheva and Piotr Garstecki provides an excellent analysis and overview of recent advances in the generation of polymer colloids by the microfluidic synthesis. This book is aimed at graduate students, scientists and engineers and it provides a well-organized guide to the rapidly expanding field of continuous microreaction synthesis.

Date: 2011-06-09

Article describes the design, synthesis and in vitro characterization of novel hybrid peptidomimetic inhibitors of STAT3 protein  

Article describes the design, synthesis and in vitro characterization of novel hybrid peptidomimetic inhibitors of STAT3 protein

Vijay M. Shahani, Peibin Yue, Steven Fletcher, Sumaiya Sharmeen, Mahadeo A. Sukhai, Diana P. Luu, Xiaolei Zhang, Hong Sun, Wei Zhao, Aaron D. Schimmer, James Turkson, Patrick T. Gunning Bioorg. Med. Chem. 2011, 19, 1823-1838.





Date: 2011-03-11

 

Doug Stephan

The Stephan group has shown that bis-phosphinimine pincer ligands are non-innocent affording access to disymmetric phosphinimine-aminophosphine pincer complexes.

Date: 2011-03-04

Nitrogen-directed ketone hydroacylation: Enantioselective synthesis of Benzoxazecinones  

Nitrogen-directed ketone hydroacylation: Enantioselective synthesis of Benzoxazecinones

Hasan A. Khan, Kevin G. M. Kou and Vy M. Dong

The vast majority of biologically active molecules consist of cyclic structures containing the element nitrogen. Hasan Khan and Kevin Kou from Vy Dong's lab report that nitrogen can be used to direct the functionalization of carbon-hydrogen bonds. Their hydroacylation method enables the synthesis of chiral benzoxazecinones in greater than 99% enantiomeric excess. These nitrogen heterocycles represent a class of unprecedented scaffolds that can now be prepared by Rhodium-catalysis. The cover design by Peter Dornan depicts a carbon-hydrogen bond undergoing activation by Rhodium.

Date: 2011-02-28

 

Andrei K. Yudin

For many years organic reactions catalyzed by transition metal complexes typically involved the formation of carbon-hydrogen and carbon-carbon bonds. These catalytic processes included reactions that form commodity chemicals on the billion pound per year scale, as well as fine chemicals that were produced on smaller scales for medicinal purposes. The book edited by Andrei Yudin with contributions from major researchers in catalysis provides an excellent overview of the catalyzed carbon-heteroatom bond forming reactions. Synthetic chemists who wish to develop their knowledge of the range of catalytic transformations of organic molecules to form carbon-heteroatom bonds, should turn the page.

Date: 2011-02-17

Resonance Energy Transfer: Beyond the Limits  

Resonance Energy Transfer: Beyond the Limits

David L. Andrews, Carles Curutchet and Gregory D. Scholes "Resonance Energy Transfer: Beyond the Limits" Laser ∓ Photon. Rev. 5, 114–123 (2011).

In pursuit of a better understanding of how electronic excitation migrates within complex structures, the concept of resonance energy transfer is being extended and deployed in a wide range of applications. Utilizing knowledge of the quantum interactions that operate in natural photosynthetic systems, wide-ranging molecular and solid-state materials are explored in the cause of more efficient solar energy harvesting, while advances in theory are paving the way for the development and application of fundamentally new mechanisms. Such state-of-the-art applications of energy transfer and the theory underpinning theses processes are reviewed in this report.

Date: 2011-01-06

Mesoporous materials: Why PMO? Towards Functionality and Utility of Periodic Mesoporous Organosilicas  

Mesoporous materials: Why PMO? Towards Functionality and Utility of Periodic Mesoporous Organosilicas

Wendong Wang, Jennifer E. Lofgreen and Geoffrey A. Ozin

Using a handful of recent trendsetting case histories, this review of multidisciplinary applications of PMO materials in chemistry and physics, materials science and engineering, biology, and medicine are demonstrated in a powerful way.

Date: 2010-12-14

Let’s get digital: digitizing chemical biology with microfluidics  

Let’s get digital: digitizing chemical biology with microfluidics

Mais J Jebrail and Aaron R Wheeler

Digital microfluidics (DMF) has recently emerged as a popular technology for a wide range of applications in chemical biology. In DMF, nL–mL droplets containing samples and reagents are controlled (i.e., moved, merged, mixed, and dispensed from reservoirs) by applying a series of electrical potentials to an array of electrodes coated with a hydrophobic insulator.

Date: 2010-10-15

Synchronized Synthesis of Peptide-Based Macrocycles by Digital Microfluidics  

Synchronized Synthesis of Peptide-Based Macrocycles by Digital Microfluidics

Mais J. Jebrail, Alphonsus H. C. Ng, Vishal Rai, Ryan Hili, Andrei K. Yudin,* and Aaron R. Wheeler*

A microfluidic technique for synchronized chemical synthesis has been developed and applied to the formation of peptide-based macrocycles and analogues with side chains appended during ring-opening. A. R. Wheeler and co-workers describe this digital microfluidic technique, in which discrete droplets of samples and reagents are controlled by electric potentials applied to an array of electrodes coated with a hydrophobic insulator, in their Communication (DOI: 10.1002/anie.201001604). Artwork: M. Jebrail/S. Youhanna.

Date: 2010-08-19

 

James Donaldson

In this Feature, Donaldson, George and Vaida outline the important atmospheric chemistry which may be initiated by long-wavelength solar radiation.

Date: 2010-07-22

 

Michael Sgro and Doug Stephan

In this paper Mike Sgro and Doug Stephan develop synthetic routes to and exchange reactions of a series of Ni-dimine complexes of olefins and alkynes.

Date: 2010-06-16

 

Dwayne Miller and Kresimir Franjic

"The cover depicts a stroboscopic flash recoring using dark field imaging to observe the supersonic ablation plume driven by an ultrafast IR laser pulse tuned to the O-H vibrational stretch of water. This work has shown that the special properties of the hydrogen bond network of water can be explicitly exploited to selectively energize the water molecules that then act as a propellant to drive even huge protein complexes into the gas phase intact. Notice the unique shape of the plume, almost like a laser beam, and the crown area where the air shock front is clearly visible. This picture illustrates an impulsive transfer of energy into the translational motions of water that replicates the input laser profile.

Date: 2010-05-21

Towards the Photonic Nose: A Novel Platform for Molecule and Bacteria Identification  

Towards the Photonic Nose: A Novel Platform for Molecule and Bacteria Identification

By Leonardo D. Bonifacio, Daniel P. Puzzo, Simon Breslav, Barbara M. Willey, Allison McGeer, Geoffrey A. Ozin*

Geoffrey Ozin and co-workers report on a novel artificial nose system dubbed the photonic nose, which is based on a simple and cost-effective pixelated array of surface-functionalized nanoporous Bragg mirrors that enable discrimination of different vapor phase analytes, exemplified by alkanes and alcohols as well as molecules comprising the headspace of different bacteria, detected and analyzed by diagnostic changes in red, green and blue primary color levels recorded by a digital camera.

Date: 2010-03-24

Bio-functional, lanthanide-labeled polymer particles by seeded emulsion polymerization and their characterization by novel ICP-MS detection  

Bio-functional, lanthanide-labeled polymer particles by seeded emulsion polymerization and their characterization by novel ICP-MS detection

Stuart C. Thickett,* Ahmed I. Abdelrahman, Olga Ornatsky, Dmitry Bandura, Vladimir Baranov* and Mitchell A. Winnik*

We present the synthesis and characterization of monodisperse, sub-micron poly(styrene) (PS) particles loaded with up to and including 107 lanthanide (Ln) ions per particle.

Date: 2010-03-11

Metal-containing polystyrene beads as standards for mass cytometry  

Metal-containing polystyrene beads as standards for mass cytometry

Ahmed I. Abdelrahman, Olga Ornatsky, Dmitry Bandura, Vladimir Baranov,* Robert Kinach, Sheng Dai, Stuart C. Thickett, Scott Tanner and Mitchell A. Winnik

We examine the suitability of metal-containing polystyrene beads for the calibration of a mass cytometer instrument, a single particle analyser based on an inductively coupled plasma ion source and a time of flight mass spectrometer.

Date: 2010-03-04

Coordination Complex SH2 Domain Proteomimetics: An Alternative Approach to Disrupting Oncogenic Protein-Protein Interactions  

Coordination Complex SH2 Domain Proteomimetics: An Alternative Approach to Disrupting Oncogenic Protein-Protein Interactions

J. A. Drewry, S. Fletcher, P. Yue, D. Marushchak, W. Zhao, S. Sharmeen, X. Zhang, A. D. Schimmer, C. Gradinaru, J Turkson & P. T. Gunning

We report the first application of coordination complexes as functional proteomimetics of the Src Homology 2 (SH2) phosphopeptide binding domain. As a proof-of-concept, functionalized bis-dipicolylamine (BDPA) copper(II) complexes are shown to disrupt oncogenic Stat3-Stat3 protein complexes and elicit promising anti-tumour activity.

Date: 2010-01-28

Nanolocomotion: Catalytic Nanomotors and Nanorotors  

Nanolocomotion: Catalytic Nanomotors and Nanorotors

Tihana Mirkovic, Nicole S. Zacharia, Gregory D. Scholes, Geoffrey A. Ozin, Small, 2010, 2, 159.

Do the nanolocomotion with me: while it is well known that solution-phase chemistry provides a powerful means to synthesize nanostructures with controlled size and shape it is only very recently that chemistry has been used as a power source to make these nanostructures move in solution well beyond the Brownian limit. The cover illustration depicts four types of motion observed for bimetallic Au-Pt nanorod motors, chemically powered by the catalytic decomposition of hydrogen peroxide fuel to water and oxygen at the platinum segment. The motility modes include straight motion with stochastically occurring turns, rotation with one end tethered to the substrate, orbiting, spinning around its center of mass, and cooperative rotational mobility of two nanorods.

Date: 2010-01-25

Quantum-Coherent Electronic Energy Transfer: Did Nature Think of It First?  

Quantum-Coherent Electronic Energy Transfer: Did Nature Think of It First?

Gregory D. Scholes
J. Phys. Chem. Letters (2010) 1, 2–8.


Dimensional photon echo experiments expose quantum biology. The image backdrop shows the core of a photosynthetic antenna protein, PE545, isolated from marine cryptophyte algae. Two bilin chromophores are seen, colored red. Foreground, clockwise from bottom left: A false- color image of fluorescence from the photosynthetic proteins in a live alga (courtesy of Dr. T. Mirkovic); two-dimensional photon echo spectra, like this one, revealing evidence for quantum coherent energy transfer in cryptophyte light-harvesting antennae at physiological conditions; cross section of a cryptophyte thylakoid membrane showing how the light-harvesting proteins are organized.

Date: 2010-01-07

Novel asymmetrically functionalized bis-dipicolylamine metal complexes: peripheral decoration of a potent anion recognition scaffold  

Novel asymmetrically functionalized bis-dipicolylamine metal complexes: peripheral decoration of a potent anion recognition scaffold

Joel A. Drewry, Steven Fletcher, Haider Hassan and Patrick T. Gunning, Org. Biomol. Chem., 2009, 7, 5074.

We report the development of a highly efficient, facile and modular synthetic route to orthogonally functionalized bis-dipicolylamine (BDPA) receptors.

Date: 2009-12-02

Electrochemical probing of HIV enzymes using ferrocene-conjugated peptides on surfaces  

Electrochemical probing of HIV enzymes using ferrocene-conjugated peptides on surfaces

Kagan Kerman and Heinz-Bernhard Kraatz
Analyst, 2009, 134, 2400 - 2404


One of the current pathways to develop inhibitors that target different steps in the life cycle of the human immunodeficiency virus (HIV) is blocking the function of the HIV-related proteins such as HIV-1 integrase (HIV-1 IN), HIV-1 reverse transcriptase (HIV-1 RT) and HIV-1 protease (HIV-1 PR), which are essential proteins that control the ability of HIV to infect cells, produce new copies of the virus, or cause disease. We have demonstrated for the first time the detection of these enzymes at nanomolar levels using ferrocene (Fc)-conjugated peptides on gold microelectrodes. The interaction between the Fc-conjugated peptides and the enzymes was studied by cyclic voltammetry. As the protein concentration increased, the electrochemical behaviour of the surface-bound Fc- bioconjugate changed, indicating that HIV protein was binding to the peptide film and encapsulating the Fc redox center on the surface. The electrochemical responses shifted to higher potentials and decreased in the current intensity, as the concentrations of the HIV-1 enzymes increased. The optimization studies were performed by changing the pH and NaCl concentration. Control experiments involved the exposure of the Fc-conjugated peptides with all the enzymes. This general procedure can be readily applied in the future to the multiplexed detection of several HIV-related proteins, as well as the high-throughput screening of candidate inhibitors for AIDS therapy.

Date: 2009-11-30

Ultrathin Inorganic Nanowires  

Ultrathin Inorganic Nanowires

Ludovico Cademartiri and Geoffrey A Ozin

Advanced Materials cover graphic illustration of a high resolution transmission electron micrograph image of ultrathin bismuth sulphide nanowires with unprecedented diameter of only 1.6 nm, a size that bridges the fuzzy regime between molecular and nanoscopic depicts the dawn of the beginning of something new and exciting in materials chemistry and nanochemistry, emerging fields that never tire of reinventing themselves.

Date: 2009-10-13

 

Noha A. Mousa, Mais J. Jebrail, Hao Yang, Mohamed Abdelgawad, Pavel Metalnikov, Jian Chen, Aaron R. Wheeler, and Robert F. Casper

Detailed view of a digital microfluidics device that extracts estradiol from tiny samples of tissue. In this segment of the process, a drop of methanol containing compounds extracted from the biological sample is circulated within a pool of isooctane to remove interfering substances. The droplet is driven from electrode to electrode by an applied AC potential. See Mousa et al. for a description of device fabrication and operation, and a discussion of its application to research and diagnostics. Each electrode is 1.5 millimeters2.

Date: 2009-10-08

Ligand-based Reactivity of a Platinum Bisdithiolene: Double Diene Addition Yields a New C2-Chiral Chelate Ligand  

Ligand-based Reactivity of a Platinum Bisdithiolene: Double Diene Addition Yields a New C2-Chiral Chelate Ligand

Mitchell J. Kerr, Daniel J. Harrison, Alan J. Lough, and Ulrich Fekl

Ligand-based additions to metal dithiolene complexes are both fundamentally intriguing and promising for applications. The cover illustrates an unprecedented double diene addition to Pt(S2C2(CF3)2)2, producing a chiral, chelating bisthioether ligand, relevant for potential applications in catalysis.

Inorg. Chem. 2009, 48, 9043-9045.



Date: 2009-09-30

Multiple modular microfluidic (M<sup>3</sup>) reactors for the synthesis of polymer particles  

Multiple modular microfluidic (M3) reactors for the synthesis of polymer particles

Wei Li, Jesse Greener, Dan Voicu and Eugenia Kumacheva

Lab Chip, 2009, 9, 2715

More...



Date: 2009-08-25

Reversible binding of CO<sub>2</sub>  

Reversible binding of CO2

Doug Stephan

It can be realized with borane-phosphane frustrated Lewis pairs (FLPs). In their Communication on page 6643 ff., Stephan, Erker and coworkers describe how the greenhouse gas CO2 is captured to form both cyclic and acyclic adducts through P -- C and O -- B bond formation. The reaction is reversed and CO2 released when the temperature of the solution is raised. Theoretical analysis describes CO2 binding by FLPs as a synchronous concerted reaction.

Date: 2009-08-20

The culmination of a rational drug discovery program of Stat3 inhibitors  

The culmination of a rational drug discovery program of Stat3 inhibitors

Steven Fletcher, Jagdeep Singh, Xiaolei Zhang, Peibin Yue, Brent D. G. Page, Sumaiya Sharmeen, Vijay M. Shahani, Wei Zhao, Aaron D. Schimmer, James Turkson, and Patrick T. Gunning

Three's company: A library of analogues of the previously reported Stat3 inhibitor S3I-201 was prepared. The most active analogues, SF-1-066 (X=NCH3) and SF-1-121 (X=O), have shown impressive in vitro and whole-cell activities that possibly result from the successful occupation of a third, hydrophobic subpocket of the Stat3 SH2 domain.

Date: 2009-08-17

Microfluidic generation of microgels from synthetic and natural polymers  

Microfluidic generation of microgels from synthetic and natural polymers

Ethan Tumarkin and Eugenia Kumacheva

Chem. Soc. Rev., 2009, 38, 2161 - 2168





Date: 2009-07-27

A MICROFLUIDIC APPROACH TO CHEMICALLY DRIVEN ASSEMBLY OF COLLOIDAL PARTICLES AT GAS-LIQUID INTERFACES  

A MICROFLUIDIC APPROACH TO CHEMICALLY DRIVEN ASSEMBLY OF COLLOIDAL PARTICLES AT GAS-LIQUID INTERFACES

Jai Il Park, Zhihong Nie, Alexander Kumachev, Ahmed I. Abdelrahman, Bernard P. Binks, Howard A. Stone, Eugenia Kumacheva

A chemically mediated microfluidic approach to the generation of particle-coated bubbles employs rapid, controllable dissolution of CO2 bubbles in a dispersion of carboxylated particles. Local increases in the acidity of the medium in the neighborhood of the bubbles lead to a change in the surface energy of the particles and their deposition on the gas-liquid interface.

Date: 2009-07-01

Dye-Anchored Mesoporous Antimony-Doped Tin Oxide > Electrochemiluminescence Cell  

Dye-Anchored Mesoporous Antimony-Doped Tin Oxide > Electrochemiluminescence Cell

Kun Hou, Daniel Puzzo, Michael G. Helander, Shun S. Lo, Leonardo D. Bonifacio, Wendong Wang, Zheng-Hong Lu, Gregory D. Scholes, Geoffery A. Ozin, Advanced Materials, 2009, 21, 2492-2496

A long sought after target in materials research has been the synthesis of high quality, optically transparent, electrically conductive thin films that simultaneously provide large surface area and nanocrystalline mesoporosity. Geoff Ozin and co-workers report a dye-anchored transparent, well-ordered mesoporous antimony-doped tin oxide film that functions as the working electrode in an electrochemiluminescent cell, suggesting opportunities for use in a range of optoelectronic applications.

Date: 2009-06-01

 

Doug Stephan

The combination of Lewis acids and bases that are sterically precluded from forming Lewis acid-base adducts, termed Frustrated Lewis pairs provide a unique route to the activation of small molecules and applications in catalysis.

Date: 2009-04-01

 

A.K.Y. Wong, Ulli Krull

This work is directed to improving the analytical performance of surfaces that can be used to develop DNA biosensors and microarrays. The concept of immobilization of oligonucleotides to surfaces for preparation of analytical technologies based on hybridization of target sequences is well established. However, the immobilization methods that are typically used tend to provide limited selectivity when compared to that seen for the same hybridization processes in bulk solution. This fact reflects the constraints that are imposed on the selective chemistry by the presence of a surface. This manuscript reports a method of surface derivatization whereby improvement of control of the surface energetics can be achieved to tune selectivity of immobilized ensembles of oligonucleotide probes.

Date:

Hybrid microfluidics: A digital-to-channel interface for in-line sample processing and chemical separations  

Hybrid microfluidics: A digital-to-channel interface for in-line sample processing and chemical separations

Mohamed Abdelgawad, Michael W. L. Watson and Aaron R. Wheeler

Microchannels can separate analytes faster with higher resolution, higher efficiency and with lower reagent consumption than typical column techniques. Unfortunately, an impediment in the path toward fully integrated microchannel-based labs-on-a-chip is the integration of pre-separation sample processing. Although possible in microchannels, such steps are challenging because of the difficulty in maintaining spatial control over many reagents simultaneously. In contrast, the alternative format of digital microfluidics (DMF), in which discrete droplets are manipulated on an array of electrodes, is well-suited for carrying out sequential chemical reactions. Here, we report the development of the first digital-channel hybrid microfluidic device for integrated pre-processing reactions and chemical separations. The device was demonstrated to be useful for on-chip labeling of amino acids and primary amines in cell lysate, as well as enzymatic digestion of peptide standards, followed by separation in microchannels. Given the myriad applications requiring pre-processing and chemical separations, the hybrid digital-channel format has the potential to become a powerful new tool for micro total analysis systems.

Date:

The  

The "Metallo-Specific" Response of Proteins: A Perspective Based on the Escherichia coli Transcriptional Regulator NikR

Sheila C. Wang, Alistair V. Dias and Deborah B. Zamble

Transition metal ions are required by all cells but an excess of metal ions beyond physiological requirements has toxic consequences. Optimal cellular concentrations of transition metals are commonly maintained by metal-responsive transcription factors that regulate genes encoding the proteins responsible for transport, sequestration and/or use of the metals. These metalloregulators must discriminate between the bioavailable metals to properly effect metal homeostasis, but how this metal selectivity is achieved is poorly understood. This perspective examines the metal-selective response of the Escherichia coli Ni(II)-responsive metalloregulator NikR. Biochemical and structural studies of E. coli NikR reveal that the mechanism of metal-selective regulation is more complex than that defined by simple metal-binding thermodynamics. Here we examine the metal-dependent allosteric changes on NikR structure that affect DNA binding and discuss the correspondence with other metalloregulators. Given what we have learned of how metal selectivity is achieved by E. coli NikR, we propose a complete scheme for the regulatory function of NikR in E. coli nickel homeostasis.

Date:

Desai-Kapral Book-blurb  

Desai-Kapral Book-blurb

Rashmi C. Desai is Professor Emeritus of Physics at the University of Toronto. Raymond Kapral is Professor of Chemistry at the University of Toronto.

Physical systems driven out of equilibrium may spontaneously evolve to form spatial structures. The molecular constituents of some systems may self-assemble to produce complex ordered structures. This book describes how such pattern formation processes occur in nonlinear dissipative systems and how they can be modeled on mesoscopic scales.

The results of experimental observations are used to introduce the diverse systems and phenomena that lead to pattern formation. The physical origins of various spatial structures are discussed, and models for their formation are constructed. In contrast to many treatments, pattern-forming processes in nonequilibrium systems, which either relax to equilibrium or are constrained to remain far from equilibrium, are treated in a coherent fashion. The book shows how near-equilibrium and far-from-equilibrium modeling concepts are often combined to describe physical systems.

This inter-disciplinary book can form the basis for postgraduate courses dealing with pattern formation and self-assembly, and can also serve as a useful reference for graduate students and researchers in a number of disciplines, including condensed matter science, nonequilibrium statistical mechanics, nonlinear dynamics, chemical biophysics and materials science & engineering.

Date:

Differential Conductivity in Self-Assembled Nanodomains of a Diblock Copolymer Using Polystyrene-block-Poly (ferrocenylethylmethylsilane)  

Differential Conductivity in Self-Assembled Nanodomains of a Diblock Copolymer Using Polystyrene-block-Poly (ferrocenylethylmethylsilane)

James K. Li, Shan Zou, David A. Rider, Ian Manners, Gilbert C. Walker (Adv. Mater. 10/2008)

The differential conductivity of the domains of a phase-segregated diblock copolymer film, polystyrene-block-poly ferrocenylethylmethylsilane (PS-b-PFEMS), is investigated using conducting-probe atomic force microscopy. Analysis of PFEMS regions show asymmetric I-V behavior, and concomitant width increase with bias indicates filling of trap states. Here, the topography is shown to correlate with the current image when scanning with an applied voltage bias.

Date:

Concepts in Nanochemistry  

Concepts in Nanochemistry

Ludovico Cademartiri and Geoffrey A. Ozin, VCH-Wiley April 2009

Authored by a rising star in the field and one of its pioneers, this textbook is ideal for interdisciplinary courses . bridging chemistry and physics, materials science and engineering, biology and medicine. Adopting a completely new and visionary approach, this is a unique learning tool, focusing on just six concepts crucial for understanding nanochemistry: surface, size, shape, self-assembly, defects and the interface of biology and nanochemistry. These concepts are elucidated through the analysis of six materials representing the real life application of the nanochemistry concepts. The teaching questions included provide real food for thought, thus training students to think as a researcher does and so develop problem solving skills.

Wiley InterScience's article about this particular cover

Date:

 

Sivaraj Baktharaman, Ryan Hili, and Andrei K. Yudin*

Amino aldehydes and amino ketones are central to organic chemistry and are indispensable in the synthesis of natural products and pharmaceuticals. Their utility stems from the broad scope of synthetic transformations available to both the amine and carbonyl functional groups. The utility of amino aldehydes and ketones is not without shortcomings as nitrogen protecting groups are usually needed in order to prevent undesired inter- and intramolecular self-condensation reactions. This review focuses on recent advances in this important area.

Date:

 

Cathy Y. Wong, Jeongho Kim, P. Sreekumari Nair, Michelle C. Nagy & Gregory D. Scholes, Relaxation in the exciton fine structure of semiconductor nanocrystals J. Phys. Chem. C Feature Article 113, 795-811 (2009).

Radiationless transitions in semiconductor nanocrystals: mechanisms for concerted energy and spin relaxation. The lowest exciton band of CdSe nanocrystals is comprised of a ladder of eight closely spaced electronic 'fine structure' states. We have found that photoexcitation energy does not equilibrate among these states in the manner of dropping down the rungs of a ladder. Instead, there are particular pathways connecting various 'rungs' (fine structure states). The dynamics of transitions between them, which span four decades of timescales, were measured using an ultrafast transient grating technique that isolates dynamics that flip the sign of the exciton total angular momentum. We conclude that the fastest relaxation in the exciton fine structure occurs mainly by a sequential mechanism involving the primary bright-to-dark transitions.

Date:

Nanochemistry: A Chemical Approach to Nanomaterials  

Nanochemistry: A Chemical Approach to Nanomaterials

2nd Editon, Authors Geoffrey A. Ozin, Andre C. Arsenault and Ludovico Cademartiri Foreword by Chad Mirkin

The global success of the 1st edition of Nanochemistry, along with exceptionally rapid change in the field, has necessitated the publication of a 2nd edition after only three years. This truly major update highlights the latest breakthroughs using more than eighty new case histories, more problem sets, and more teaching principles. Nanotechnology is touted to begin a new era by bringing us materials that were not available before. This book describes the fascinating chemistry behind nanotechnology in a clear and easy to read style. Aimed at teachers, graduate students and advanced undergraduates it provides an authoritative, rigorous and hype-free guide to this burgeoning field. For those who already have some knowledge of the subject, the book remains invaluable as a reference and source of inspiration for future research or teaching. With a combined total of over forty years teaching and research experience, the authors are leaders in the fields of materials chemistry and nanochemistry. They have chosen to focus on concepts rather than formulas whilst describing all the techniques commonly used to synthesize nanomaterials. Problem sets are used to encourage students to think creatively and laterally about what they have learnt. The questions are designed to draw connections between subjects, fields and topics - of fundamental importance for anyone intending to work in such an interdisciplinary field. Suitable for those coming from a physics, biology, medicine, materials science, engineering or chemistry background, the book is ideal for whoever needs a birds-eye view of the field. The extensive bibliography allows the reader to find any level of detail behind each of the subjects. Nowhere else in the literature is it possible to find such a comprehensive and up-to-date look at the chemistry of nanotechnology.

Extracts from reviews of the 1st Edition:

  • A gem in the scientific literature...a beautifully written and richly illustrated book that is unlike any other. Science, 21 July 2006, Vol 313.
  • An invaluable reference book for undergraduate and graduate students. As a superb textbook for teaching of materials chemistry and nanotechnology. Advanced Materials, 1/2006.
  • ...wonderful book....insightful perspective on nanochemistry. Physical Sciences Educational Reviews, October 2006, Vol. 7, Issue 2


Date:

Spatially Localized Photoluminescence at 1.5 Micrometers Wavelength in Direct Laser Written Optical Nanostructures  

Spatially Localized Photoluminescence at 1.5 Micrometers Wavelength in Direct Laser Written Optical Nanostructures

Sean Wong, Oliver Kiowski, Manfred Kappes, Jƶrg K. N. Lindner, Nirajan Mandal, Frank C. Peiris, Geoffrey A. Ozin, Michael Thiel, Markus Braun, Martin Wegener, Georg von Freymann. Advanced Materials, Published Online: Oct 6 2008 6:36AM

A 3D direct laser writing (3D DLW) compatible photoresist, consisting of erbium-doped arsenic trisulfide (Er:As2S3) has been developed. This photoresist simultaneously possess a refractive index (n) of 2.45 and photoluminescence at 1.5 m wavelength that is also spatially localizable. This enables 3D DLW to produce high-refractive index photonic structures with spatially selective optical activity without the need for post-processing steps.

Date:

Preparation of Chiral Diamines by the Diaza-Cope Rearrangement  

Preparation of Chiral Diamines by the Diaza-Cope Rearrangement

Hyunwoo Kim, Soon Mog So, B. Moon Kim and Jik Chin

Chiral vicinal diamines are regarded as privileged structures for making drugs and catalysts. This review describes a highly efficient method for making a wide variety of chiral vicinal diamines in enantiomerically pure form by the diaza-Cope rearrangement reaction.

Date:

Synthesis of Chiral Amines Using α-Amino Aldehydes  

Synthesis of Chiral Amines Using α-Amino Aldehydes

Ryan Hili, S. Baktharaman, Andrei K. Yudin

The cover picture is an attempt to represent a cornucopia of molecules that are derived from α-amino aldehydes. One hundred years ago, Emil Fischer attempted to prepare glycinal, a prototypical .- amino aldehyde. Although glycinal resisted isolation and was found to be too unstable, it did provide a foundation for numerous synthetic studies of related molecules. Over the last century this field has flourished, proving the lasting value of these important synthetic intermediates. A. K. Yudin et al. summarize the latest trends in α- amino aldehyde synthesis and applications on p. 5201ff. The cover art was created by Mr. Ryan Hili. The authors gratefully acknowledge ongoing financial support from NSERC.

Date:

Creating Helices with amino acids Angew Chem Int Ed (2008)  

Creating Helices with amino acids Angew Chem Int Ed (2008)

Hyunwoo Kim, Soon Mog So, Cindy Pai-Hui Yen, Elisangela Vinhato, Alan J. Lough, Jong-In Hong, Hae-Jo Kim, and Jik Chin, Angew. Chem. Int. Ed. 2008, 47, 8657-8660

A spiral staircase follows the many helical structures in nature (DNA, protein etc.). Amino acids that form alpha-helical proteins in biology can also be used to generate small helical structures with 2,2.-dihydroxybenzophenone. Signaling groups can be attached to allow the receptor to sense amino acid enantiopurity.

Date:

Heterolytic Dihydrogen Activation by a Frustrated Carbene-Borane Lewis Pair / Hydrogen and Amine Activation by a Frustrated Lewis Pair of a Bulky N-Heterocyclic Carbene and B(C6F5)3 (Angew. Chem. Int. Ed. 39/2008) (p 7369)  

Heterolytic Dihydrogen Activation by a Frustrated Carbene-Borane Lewis Pair / Hydrogen and Amine Activation by a Frustrated Lewis Pair of a Bulky N-Heterocyclic Carbene and B(C6F5)3 (Angew. Chem. Int. Ed. 39/2008) (p 7369)

Dirk Holschumacher, Thomas Bannenberg, Cristian G. Hrib, Peter G. Jones, Matthias Tamm, Preston A. Chase, Douglas W. Stephan

Forcing a square peg into a round hole: tBu2ImC: and B(C6F5)3 form a frustrated Lewis pair (FLP),allowing the synergistic activation of H2. On page 7428 ff.,M. Tamm et al. describe how the irreversible formation of an abnormal carbene-borane adduct eliminates mismatching between acid and base so that this system can circumvent frustration at the expense of activity. In addition, D. W. Stephan and P. A. Chase demonstrate on page 7433 ff. that this FLP combination not only effects heterolytic cleavage of H2, but also of amine N-H bonds.

Date:

Photonic Ink and Elastic Ink Lab-to-Market  

Photonic Ink and Elastic Ink Lab-to-Market

Ozin, Z. Anorg. Allg. Chem., 2008, 634, 1871-2100

A notable trend these days amongst academics, especially in the fields of information technology, biotechnology and nanotechnology, is the increasing tendency to transfer the fruits of their research into the marketplace. Nowhere is this more apparent than in the globally burgeoning and highly competitive area of nanotechnology. Particularly interesting is the large number of spin-off companies now emerging from universities all racing to develop, manufacture and commercialize nanotechnology based on the potential of a cornucopia of new nanomaterials in diverse areas from electronics to photonics, biometrics to cancer therapy. In this paper I will present a personal account of some of our recent research in the area of photonic crystals that has evolved over the last ten years from a laboratory curiosity to two new nanotechnology platforms, affectionately called P-Ink and Elast-Ink. These nanotechnology platforms are both founded on active color tuning of opals, a capability that provides electrical and mechanical access to materials with any visible color you want, including the invisible ultraviolet and near infrared wavelength range. P-Ink is made of a metallopolymer opal gel that reversibly swells and shrinks with application and removal of a voltage. Elast-Ink is made of an elastomeric opal that undergoes reversible dimensional changes on applying and removing a mechanical force. P-Ink and Elast-Ink actively tuned opals show considerable promise for the development of new generation of full color displays, biometric security and anti-counterfeiting systems.

Date:

Quantum dots as donors in fluorescence resonance energy transfer for the bioanalysis of nucleic acids, proteins, and other biological molecules  

Quantum dots as donors in fluorescence resonance energy transfer for the bioanalysis of nucleic acids, proteins, and other biological molecules

Ulli Krull

Quantum dots (QDs) have a number of unique optical properties that are advantageous in the development of bioanalyses based on fluorescence resonance energy transfer (FRET). Researchers have used QDs as energy donors in FRET schemes for the analysis of nucleic acids, proteins, proteases, haptens, and other small molecules. Superior brightness, resistance to photobleaching, greater optimization of FRET efficiency, and/or simplified multiplexing are possible with QD donors.

Date:

Stoichiometric and Catalytic Activation of P-H and P-P bonds  

Stoichiometric and Catalytic Activation of P-H and P-P bonds

Sharonna Greenberg and Douglas W. Stephan, Chem. Soc. Rev., 2008, 37, 1482

The abilities of transition metal species to activate P-H and P-P bonds are emerging. Such investigations provide novel M-P species, as well as stoichiometric and catalytic routes to P(III) compounds. The application of organometallic approaches and methodologies to phosphorus chemistry is providing emerging, stoichiometric and catalytic routes to phosphorus compounds and materials. This tutorial review surveys recent advances, with a focus on the activation of P-H and P-P bonds. The isolation of novel M-P species provides insight, while stoichiometric and catalytic reactivity expands the arsenal of synthetic strategies leading to P(III) compounds.

Date:

Molecular Approaches towards the Inhibition of the Signal Transducer and Activator of Transcription 3 (Stat3) Protein  

Molecular Approaches towards the Inhibition of the Signal Transducer and Activator of Transcription 3 (Stat3) Protein

ChemMedChem, 2008, 3, 1159-1168. Steven Fletcher, James Turkson and Patrick T. Gunning

Stat3 inhibition represents an exciting new approach to the treatment of cancer. The advances in the direct molecular inhibition of Stat3 are highlighted through discussion of the various inhibitors currently under investigation, including peptide sequences, peptidomimetics, small molecules and platinum-based agents.

Date:

Large-Scale Synthesis of Ultrathin Bi2S3 Necklace Nanowires  

Large-Scale Synthesis of Ultrathin Bi2S3 Necklace Nanowires

Angew. Chem. Int. Ed. 2008, 20, 3652, Ludovico Cademartiri, Reihaneh Malakooti, Paul G. O'Brien, Andrea Migliori, Srebri Petrov, Nazir P. Kherani, Geoffrey A. Ozin

Ultrathin necklaces of Bi2S3 nanowires can be synthesized in solution on a gram scale and using cheap and non-air-sensitive reagents. Despite their small size, these nanostructures show quantum confinement effects never before observed in Bi2S3 at room temperature and a semiconductivity which bodes well for their use in flexible electronics devices.

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  	  Controlling the Optical Properties of Inorganic Nanoparticles  

Controlling the Optical Properties of Inorganic Nanoparticles

Gregory D. Scholes, Adv. Funct. Mater. (2008) 18, 1157 - 1172

The size tunability and close relationship of inorganic nanoparticles to bulk semiconductors have inspired intense study of these materials. Applications, such as diodes and lasers, can take advantage of the light-emitting properties of nanoscale systems, as pictured on the cover. A growing and important area of application for these materials is renewable energy. A challenge for researchers is to elucidate how to design and control the desirable optical properties of nanoparticles by manipulating electronic structure using chemical design.

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Development of Analytical Methods for Multiplex Bio-assay with Inductively Coupled Plasma Mass Spectrometry  

Development of Analytical Methods for Multiplex Bio-assay with Inductively Coupled Plasma Mass Spectrometry

O.I. Ornatsky , R. Kinach , D.R. Bandura , X. Lou , S.D. Tanner , V.I. Baranov , M. Nitz and M.A. Winnik, Journal of Analytical Atomic Spectrometry , 2008, 23, 463-469

Advances in the development of highly multiplexed bio-analytical assays with inductively coupled plasma mass spectrometry (ICP-MS) detection are discussed. Use of novel reagents specifically designed for immunological methods utilizing elemental analysis is presented. The major steps of method development, including selection of elements for tags, validation of tagged reagents, and examples of multiplexed assays, are considered in detail. The paper further describes experimental protocols for elemental tagging of antibodies, immunostaining of live and fixed human leukemia cells, and preparation of samples for ICP-MS analysis. Quantitative analysis of surface antigens on model cell lines using a cocktail of seven lanthanide labeled antibodies demonstrated high specificity and concordance with conventional immunophenotyping.

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Visualization of Stacking Faults and their Formation in Colloidal Photonic Crystal Films (Adv. Mater. 6/2008)  

Visualization of Stacking Faults and their Formation in Colloidal Photonic Crystal Films (Adv. Mater. 6/2008)

Van Vekris, Vlad Kitaev, Doug Perovic, Stewart. Aitchison and Geff Ozin

A colloidal crystal with fundamental photonic stopband in the near-infrared and higher-frequency photonic bands in the visible was designed to yield impressive sensitivity to stacking fault formation. Diagnostic patterns of brilliant colors emerge, providing a powerful spectroscopic tool to elucidate the origin, nature, and control of stacking faults.

Date:

Ultra-thin Sb2S3 Nanowires  

Ultra-thin Sb2S3 Nanowires

R. Malakooti, L. Cademartiri, A. Migliori, G. A. Ozin

A simple synthetic route is described which allows the reproducible synthesis of ultra-thin Sb2S3 nanowires with a diameter below 2 nm and micron lengths. The colloidal nature of such nanowires and their unparalleled small diameters makes them amenable to solution processing and deposition on flexible substrates. The interest in high performance metal chalcogenide nanothermoelectric materials with reduced dimensionality motivates this work and further encourages the exploration of synthetic routes to enable the next generation of practical thermoelectric nanostructures for possible use in solid-state refrigeration and power generating systems.

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Metal-Free Catalytic Hydrogenation  

Metal-Free Catalytic Hydrogenation

Preston A. Chase, Gregory C. Welch, Titel Jurca, and Douglas W. Stephan*

Off the beaten path aptly describes a main-group alternative for catalyzing hydrogenation reactions using H2. Whereas the main road is based on transition metals, D.W. Stephan and co-workers offer a new path in their Communication on page 8050 ff. with metal-free phosphonium borates, which effect the reduction of sterically hindered imines and aziridines under relatively mild conditions. The cover picture illustrates this alternative but parallel route with the bicycle and pedestrian paths of the "Promenade" in Muenster, Germany.

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Nanorod Heterostructures Showing Photoinduced Charge Separation  

Nanorod Heterostructures Showing Photoinduced Charge Separation

Sandeep Kumar, Marcus Jones, Shun S. Lo, Gregory D. Scholes, Small (2007) 3(9), 1633-1639.

Size- and shape-dependent property modifications of semiconductor nanocrystals have been a subject of intense interest because of their potential for future engineering devices. The bandgap and related optical-property tuning of these materials are mainly governed by the nature of their band edges. In addition, fusing one type of nanocrystal over another enables further control of material properties that are dependent on the relative alignments of their energy levels. On a molecular scale, the synthesis of supramolecular compounds has inspired advances in theories for photoinduced charge transfer. Heterostructured nanocrystals potentially provide a nanoscale analog of such systems. A method for preparing heterostructured nanocrystals of complex morphologies showing photoinduced charge separation is presented. It is shown that the energy and lifetime of the charge-transfer photoluminescence band can be tuned by changing the relative alignment of band edges in CdSe/CdTe heterostructure nanorods. The long-lived charge transfer states in these type II semiconductors may make them attractive for photovoltaic applications.

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Low-lying exciton states determine the photophysics of semiconducting single wall carbon nanotubes  

Low-lying exciton states determine the photophysics of semiconducting single wall carbon nanotubes

Gregory D. Scholes, Sergei Tretiak, Timothy J. McDonald, Wyatt K. Metzger, Chaiwat Engtrakul, Garry Rumbles and Michael J. Heben (contribution from NREL, UofT, and LANL)

Single wall carbon nanotubes are extraordinary carbon-compounds that can be up to millimeters in length. It is concluded that the interplay of multiple exciton states--rather than only one as is well known for molecules--determines fluorescence emission. On the basis of a combination of experiment and theory, it is concluded that a kinetic model that captures the nonradiative relaxation among four low-lying exciton states is essential to interpret the photophysics of single wall carbon nanotubes.

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Novel Hydrido-Ruthenium(II) Complexes of Histidine Derivatives and Their Application in the Hydrogenation of Ketones  

Novel Hydrido-Ruthenium(II) Complexes of Histidine Derivatives and Their Application in the Hydrogenation of Ketones

Christine Sui-Seng, Alen Hadzovic, Alan J. Lough, and Robert H. Morris, Dalton Transactions , 2007, 2536

The complexes RuHCl((R)-binap)(L-NH2) with L-NH2 = (S)-histidine-Me-ester (1), histamine (3), (S)-histidinol (4) or 1-Me-(S)-histidine-Me-ester (5), and RuHCl((S)-binap)(L-NH2) with L-NH2 = (S)-histidine-Me-ester (2) have been prepared in 60–81% overall yields in a one-pot, three-step procedure from the precursor RuCl2(PPh3)3. Their octahedral structures with hydride trans to chloride were deduced from their NMR spectra and confirmed by the results of a single crystal X-ray diffraction study for complex 3. Under H2 and in the presence of KOtBu, complexes 1–5 in 2-propanol form moderately active catalyst precursors for the asymmetric hydrogenation of acetophenone to 1-phenylethanol. Complex 5 is more active and enantioselective than complexes 1–4, allowing complete conversion to 1-phenylethanol in 46% e.e. (R) in 72 h at 20 ?C under 1 MPa of H2 with substrate : catalyst : base = 2000 : 1 : 30. Complex 5, when activated, also catalyzes the hydrogenation of trans-4-phenyl-3-buten-2-one to exclusively the allyl alcohol 4-phenyl-3-buten-2-ol under 2.7 MPa of H2 at 50 ?C in 2-propanol. This selectivity for C=O versus C=C hydrogenation is consistent with a mechanism involving the outer sphere transfer of hydride and proton to the polar bond. Further extensions to complexes with peptides with N-terminal histidine groups appear feasible on the basis of the current work.

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Properties of the Polyhydride Anions [WH<SUB>5</SUB>(PMe<SUB>2</SUB>Ph)<SUB>3</SUB>]<SUP>-</SUP> and [ReH<SUB>4</SUB>(PMePh<SUB>2</SUB>)<SUB>3</SUB>]<SUP>-</SUP> and Periodic Trends in the Acidity of Polyhydride Complexes  

Properties of the Polyhydride Anions [WH5(PMe2Ph)3]- and [ReH4(PMePh2)3]- and Periodic Trends in the Acidity of Polyhydride Complexes

Justin G. Hinman, Alan J. Lough, and Robert H. Morris

The new anionic complexes [K(18-crown-6)][WH5(PMe2Ph)3], [K(1,10-diaza-18-crown-6)][WH5(PMe2Ph)3], [K(2,2,2-crypt)][ReH4(PMePh2)3], and [K(1,10-diaza-18-crown-6)][ReH4(PMePh2)3] were prepared by reaction of KH/crown or KH/crypt with the appropriate neutral polyhydride WH6(PMe2Ph)3 or ReH5(PMePh2)3. The rate of deprotonation of the rhenium hydride in THF is much greater for the reaction involving crypt compared with that of crown. The structure of [ReH4(PMePh2)3]- is distorted pentagonal bipyramidal as determined by an X-ray diffraction study of the crypt salt. No hydridic-protonic M-H···HN bonding is detected between the hydrides of the anionic hydrides and the amino hydrogens of the cations [K(1,10-diaza-18-crown-6)]+ suggesting that stronger M-H···K interactions are present. Acid dissociation constants Ka of polyhydride complexes in THF, approximately corrected for ion pairing, are determined by NMR in order to better understand the periodic trends of metal hydrides. The pKTHF of (WH6(PMe2Ph)3/[WH5(PMe2Ph)3]-) is 42 ± 4 according to the equilibrium set up by reacting WH6(PMe2Ph)3 with [K(2,2,2-crypt)][ReH6(PCy3)2]. The pKTHF for ReH5(PMePh2)3 can be estimated as greater than the pKαTHF of 38 for HNPh2 and less than the pKαTHF of 41 for ReH7(PCy3)2. Reaction of the phosphazene base P4-tBu with ReH7(PCy3)2 gave an equilibrium with [HP4-tBu]+[ReH6(PCy3)2]- whereas reaction with WH6(PMe2Ph)3 gave an equilibrium with [HP4-tBu]+[WH5(PMe2Ph)3]-. From these and a related equilibrium, the pKTHF of [HP4-tBu]+ is found to be 40 ± 4. In general, neutral complexes MHx(PR3)n (M = W, Re, Ru, Os, Ir; n = 3, 2) studied to date have pKαTHFvalues from 30 to 44 on going from phenyl-substituted to alkyl-substituted phosphine ligands whereas MHx(PR3)n+(M = Re, Fe, Ru, Os, Co, Rh, Ni, Pd, Pt; n = 4, 3), including diphosphine ligands ((PR3)2 = PR2-PR2), have values from 12 to 23. From the equilibrium established from the reaction of [HP2-tBu][BPh4] and [K(2,2,2-crypt)][OP(OEt)2NPh], [HP2-tBu]+ was calculated to have a pKTHF of 30 ± 4. The equilibrium constant for the similar deprotonation reaction with [K(18-crown-6)][{ReH2(PMePh2)2}2(α-H)3] confirmed this value.

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Perfluorinated acids in arctic snow: New evidence for atmospheric formation  

Perfluorinated acids in arctic snow: New evidence for atmospheric formation

Young, Cora J.; Furdui, Vasile I.; Franklin, James; Koerner, Roy M.; Muir, Derek C.G.; Mabury, Scott A. "Perfluorinated acids in Arctic snow: New evidence for atmospheric formation". Environmental Science and Technology 2007, 41, 3455-3461

Perfluorinated acids (PFAs) are ubiquitously found in water and biota, including remote regions such as the High Arctic. Under environmental conditions, PFAs exist mainly as anions and are not expected to be subject to long-range atmospheric transport in the gas phase. Fluorinated telomer alcohols (FTOHs) are volatile and can be atmospherically oxidized to form perfluorocarboxylic acids. Analogously, fluorosulfamido alcohols can be oxidized to form perfluorooctane sulfonate (PFOS). High Arctic ice caps experience contamination solely from atmospheric sources. By examining concentrations of PFAs in ice cap samples, it is possible to determine atmospheric fluxes to the Arctic. Ice samples were collected from high Arctic ice caps in the spring of 2005 and 2006. Samples were concentrated using solid phase extraction and analyzed by LC-MS-MS. PFAs were observed in all samples, dating from 1996 to 2005. Concentrations were in the low-mid pg L-1 range and exhibited seasonality, with maximum concentrations in the spring-summer. The presence of perfluorodecanoic acid and perfluoroundecanoic acid on the ice cap was indicative of atmospheric oxidation as a source. Ratios of PFAs to sodium concentrations were highly variable, signifying PFA concentrations on the ice cap were unrelated to marine chemistry. Fluxes of the PFAs were estimated to the area north of 65°N for the 2005 season, which ranged from 114 to 587 kg year-1 for perfluorooctanoic acid (PFOA), 73 to 860 kg year-1 for perfluorononanoic acid (PFNA), 16 to 84 kg year-1 for PFDA, 26 to 62 kg year-1 for PFUnA and 18 to 48 kg year-1 for PFOS. The PFOA and PFNA fluxes agreed with FTOH modelling estimations. A decrease in PFOS concentrations through time was observed, suggesting a fast response to changes in production. These data suggest that atmospheric oxidation of volatile precursors is a primary source of PFAs to the Arctic.

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Materials Chemistry for Low-k Materials  

Materials Chemistry for Low-k Materials

Hatton, B.D., Landskron, K., Hunks, W.J., Bennett, M.R., Shukaris, D., Perovic, D.D., Ozin, G.A., 2006, Materials Chemistry for Low-k Materials, Materials Today 9 , 22-31 ( front cover ).

The microelectronics industry is constantly trying to reinvent itself, to find new technological solutions to keep pace with the trend of increasing device densities in ultra-large-scale integrated (ULSI) circuits. Integral in this development has been the replacement of the conventional Al/SiO 2 metal and dielectric materials in multilevel interconnect structures. Higher-conductivity Cu has now successfully replaced Al interconnects, but there is still an urgent need for new low dielectric constant (low-k) materials, as an interlayer dielectric. This paper critically appraises low-k materials under development as interlayer dielectrics (ILD) materials. It delineates how recent developments in materials chemistry, particularly the recent introduction of a new class of materials called periodic mesoporous organosilicas (PMOs), invented in our laboratory may provide novel solutions to the low-k challenge.

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Suppression of aqueous surface hydrolysis by monolayers of short chain organic amphiphiles  

Suppression of aqueous surface hydrolysis by monolayers of short chain organic amphiphiles

Daniel Clifford, Thorsten Bartels-Rausch and D.J. Donaldson Phys. Chem. Chem. Phys. , 2007 , 9 , 1362-1369

Aqueous aerosols and other water surfaces in the environment may be coated with organic films, which can give rise to significant effects on gas-solution transport and surface reactivity. We have used a surface active fluorescent pH probe to examine the hydrolysis of nitric acid and ammonia at both the uncoated and the organic-coated air-water interface. For uncoated samples, a transient change in pH is observed at the interface upon introduction of acid or base vapour, followed by a relaxation to a final pH which is different than the initial value, and equal to the final bulk pH. Solutions having monolayer and sub-monolayer films of 1-octanol do not display the transient, but do show the same long-time change in pH. The degree of suppression of the surface pH transient depends directly on the amount of octanol present at the surface, however when monolayers of butanol and of uncompressed stearic acid are present at the surface there is little difference seen from the clean interface. We propose that the surface component of the hydrolysis reaction depends directly on the concentration of available water at the interface.

In the upper half of the figure, the time dependence of surface pH is shown after gas phase nitric acid is introduced above a bare interface (in blue) and one having a monolayer of 1-octanol at the surface (red). Beside these traces are photos of the fluorescence observed with higher (top) and lower (bottom) values of the surface pH. The lower portion of the figure shows a cartoon depicting the inhibition of surface hydrolysis by an organic monolayer.

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Properties of Single Organic Molecules on Crystal Surfaces  

Properties of Single Organic Molecules on Crystal Surfaces

John Polanyi

Within nanoscience, an emerging discipline is the study of the physics and chemistry of single molecules. Molecules may be considered as the ultimate building blocks, and are therefore interesting for the development of molecular devices and for surface functionalization. Thus, it is interesting to study their properties when adsorbed on a suitable substrate such as a solid or crystal surface, and also for their potential applications in nano- or molecular-electronics and nansensing. Investigations have been made possible by the advent of high resolution surface imaging and characterization techniques, commonly referred to as Scanning Probe Microscopes.

This book focuses on the fascinating properties of the single molecules, and the difference between single molecules and ensembles of molecules is emphasized. As the first book intended for graduate courses in the field, after each chapter, students should be able to answer the question: What physical or chemical properties do you learn from a single molecule in this particular context? Contributed by experts across the disciplines, the book provides useful reference material for specialized practitioners in surface science, nanoscience and nanoelectronics.

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Polymer nanostructured material for the recording of biometric features  

Polymer nanostructured material for the recording of biometric features

Hung H. Pham, Ilya Gourevich, James E. N. Jonkman and Eugenia Kumacheva

The cover shows three spatially overlapping biometric features recorded in the same location of the nanostructured polymer material and selectively accessed under particular, well-defined conditions. We conceptualized, designed, synthesized and fabricated a polymer multiphase nanostructured material that was used as a medium for the recording of biometric features. The material was produced from polymer multilayer particles containing three fluorescent dyes with largely non-overlapping absorption and emission spectra. Recording was conducted by selective photobleaching of the dyes localized in the different phases of the film. We demonstrate two distinct approaches to the recording of biometric features in the polymer material. In the first strategy, we encrypted in the polymer films full colour photographs with different shades of grey. In the second approach, we recorded three spatially overlapping biometric features in the same location of the material with no spectral overlap between them. Each feature was accessed by irradiating the material at a specific well-defined wavelength. The reported material can be used as a medium for the recording of biometric features of holders of identification documents.

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Imprinting and locking chiral memory for stereoselective catalysis  

Imprinting and locking chiral memory for stereoselective catalysis

Jik Chin, Yong S. Chong, Rhiana Bobb, Lisa Studnicki and Jong-In Hong

The image shows a right handed double helix used to imprint and then padlock a chiral Möbius strip. This is much like using an amino acid to imprint our diamine based metal complex and then lock the chirality by acylation.

A metal complex that is made with an achiral ligand is imprinted with a chiral amino acid. The metal complex retains the chiral memory even when the amino acid is displaced with an achiral amine. This chiral memory can be covalently locked by acylation. The imprinted and locked metal complex can be used as a stereoselective catalyst for ring opening of epoxides. It can also be used as a stereoselective receptor for amino acids and amines.

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How energy funnels from the phycoerythrin antenna complex to Photosystem I and Photosystem II in cryptophyte Rhodomonas CS24 cells  

How energy funnels from the phycoerythrin antenna complex to Photosystem I and Photosystem II in cryptophyte Rhodomonas CS24 cells

Chantal D. van der Weij-De Wit, Alexander B. Doust, Ivo H. M. van Stokkum, Jan P. Dekker, Krystyna E. Wilk, Paul M. G. Curmi, Gregory D. Scholes, and Rienk van Grondelle

Photosynthetic organisms capture incident light in vast arrays of light-harvesting proteins. These antenna proteins then shuttle the absorbed solar energy, through a series of steps often involving ~200 molecules, to the core of photosystems I and II. It is there that solar energy conversion takes place, concomitant with the evolution of an important biproduct: oxygen. Ultimately ATP--Nature's energy currency--is created. The initial steps of this chain of events occur with remarkable efficiency (>95% quantum yield) and on a heirarchy of time- and length-scales; femtoseconds to nanoseconds, Angstroms to several nanometers. We report an investigation of the ultrafast excitation energy migration dynamics in intact (living) cells of the photosynthetic cryptophyte Rhodomonas CS24. This red organism lives in marine environments off the coast of Sydney, Australia. Our work shows that the antenna proteins function more effectively in the organism than in isolation. We expose the dynamics of this complex machinery, thus providing functional picture of the nanoscale organization of the photosynthetic apparatus.

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Coherent Control of Retinal Isomerization in Bacteriorhodopsin  

Coherent Control of Retinal Isomerization in Bacteriorhodopsin

V.I. Prokhorenko, A.M. Nagy, S.A. Waschuk, L.S. Brown, R.R. Birge, R.J.D. Miller, Coherent Control of Retinal Isomerization in Bacteriorhodopsin, Science 2006, 313, 1257-1261

Do we live in a Quantum World?

Quantum mechanics dictates that all matter has an inherent wave property. On a molecular scale, this property can lead to destructive and constructive interferences that have a pronounced effect on transmission probabilities along reaction coordinates, particularly the photo-induced isomerization of retinal molecule in rhodopsins. In bacteriorhodopsin, random fluctuations among the enormous number of degrees of freedom of protein might be expected to cancel any quantum interference effects. However, the proteins are highly evolved structures and the question arises whether the phases of the underlying matter waves could play a role or even be manipulated in directing biological processes. To answer this question, Valentyn I. Prokhorenko et al. (research team of Prof. R.J. Dwayne Miller) has performed an experimental test of possibility to manipulate the isomerization quantum yield of the retinal in bacteriorhodopsin, a key molecule in light capture and vision, at very weak excitation level (relevant to natural biological conditions) using coherent control approach. By manipulating the shape of the light pulse that jump-starts retinal's transformation, the UofT researchers were able to enhance or suppress the retinal isomerization yield by 20% in either direction and found the effect to depend on the phase of the light field or timing of the various excited nuclear motions. The latter effect is consistent with constructive and destructive wave interference effects along the reaction coordinate defined by the protein structure. This experimental observation illustrates that the wave properties of matter can play a role in biological processes to the point that they can even be manipulated.

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Curling Colloidal Photonic Crystals  

Curling Colloidal Photonic Crystals

Evangellos Vekris, Geoffrey A. Ozin, Vladimir V. Kitaev

The cover features a schematic illustration (right) and three representative electron microscopy images (left) of photonic-crystal strips with controlled curvature. The curvature is induced by infiltration of polymer opal with alkoxide precursors to attain a nanoscale overlayer that experiences controllable shrinkage upon hydrolysis. Both continuity and high structural order are perfectly preserved throughout precursor infiltration and polymer microsphere removal.

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Laser-Induced Spatial Symmetry Breaking in Quantum and Classical Mechanics  

Laser-Induced Spatial Symmetry Breaking in Quantum and Classical Mechanics

Ignacio Franco and Paul Brumer

Phase-controllable transport in laser-irradiated spatially symmetric systems is shown to arise both quantum mechanically and classically from a common field-driven interference mechanism. Specifically, the quantum-to-classical transition for symmetry breaking in a quartic oscillator driven by a field and its second harmonic is studied. For this, a double perturbation theory in the oscillator anharmonicity and external field strength, that admits a smooth classical limit, is carried out in the Heisenberg picture. The interferences responsible for the symmetry breaking are shown to survive in the classical limit and are the origins of classical control. Differences between reflection symmetry that plays a key role in the analysis, and parity that does not, are discussed.

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Ketenes  

Ketenes

Thomas T. Tidwell

My book is Ketenes 2nd ed, published by Wiley, Hoboken, New Jersey, 2006. Wiley published the first edition in 1995, but were then on Park Avenue in New York City, so they have moved a step down. The book has 656 pages and 3,300 references. The first book on the subject was "Die Ketene", by Hermann Staudinger (the founder of this field, and the discoverer of the first ketene in 1905), published in 1912. I organized a Symposium for the Ketene Centennial as part of Pacifichem in Honolulu in Dec, 2005, and wrote a history of the discovery published in Angewandte Chemie Int. Ed. 2005, 44, 5778-5785.

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From colour fingerprinting to the control of photoluminescence in elastic photonic crystals  

From colour fingerprinting to the control of photoluminescence in elastic photonic crystals

ANDRÉ C. ARSENAULT, TIMOTHY J. CLARK, GEORG VON FREYMANN, LUDOVICO CADEMARTIRI, RICCARDO SAPIENZA, JACOPO BERTOLOTTI, EVANGELLOS VEKRIS, SEAN WONG, VLADIMIR KITAEV, IAN MANNERS, R. Z. WANG, SAJEEV JOHN, DIEDERIK WIERSMA and GEOFFREY A. OZIN

In photonic crystals (PCs), strong scattering and destructive wave interference lead to a modification of the photon density of states in particular energy regions and along certain crystallographic directions1, 2. The consequences of this range from suppression and enhancement of luminescence3-7 to narrow-band bright reflections useful for colour sensors8, 9, displays10 and tuneable filters11-14. Here we demonstrate large-area films of porous elastomeric photonic crystals (EPCs) that are compressively?decompressively cycled to reversibly shift the position of the photonic band structure over a large wavelength range. Owing to their low compressive threshold, such porous EPCs can be used for imaging that is pressure and time sensitive, for example, to obtain colour fingerprints with high accuracy. Furthermore, by incorporating luminescent PbS quantum dots in the EPCs, the photonic stop-gap can be tuned through the near-infrared (NIR) quantum dot photoluminescence (PL) peak. Thereby we demonstrate a tuneable modification of photonic characteristics, including the suppression and enhancement in emission and dynamic modification of luminescence lifetimes.

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Conformational chemistry of surface-attached calmodulin detected by acoustic shear wave propagation  

Conformational chemistry of surface-attached calmodulin detected by acoustic shear wave propagation

Xiaomeng Wang, Jonathan S. Ellis, Emma-Louise Lyle, Priyanka Sundaram and Michael Thompson

A thickness shear-mode acoustic wave device, operated in a flow-through format, was used to detect the binding of ions or peptides to surface-attached calmodulin. On-line surface attachment of the protein was achieved by immobilisation of the biotinylated molecule via a neutravidinbiotin linkage onto the surface of the gold electrode of the detector. The interaction between calmodulin, and calcium and magnesium ions induced an increase in resonant frequency and a decrease in motional resistance, which were reversible on washing with buffer. Interestingly, the changes in resonant frequency and motional resistance induced by the binding were opposite to the normal operation of the detector. The response was interpreted as a decrease in surface coupling (partial slip at the liquid/solid interface) instigated by exposure of hydrophobic domains on the protein, and an increase in the thickness, and hence effective wavelength, of the acoustic device, corresponding to an increase in the length of calmodulin by 1.5 . This result is consistent with the literature value of 4 . In addition, the interaction of the protein with peptide together with calcium ions was detected successfully, despite the relatively low molecular mass of the 2-kDa peptide. These results confirm the potential of acoustic wave physics for the detection of changes in the conformational chemistry of monolayer of biochemical macromolecules at the solid/liquid interface.

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Formation of C<sub>7</sub>F<sub>15</sub>COOH  (PFOA) and other Perfluorocarboxylic acids (PFCAs) during the Atmospheric Oxidation of 8:2 Fluorotelomer Alcohol (<em>n</em>-C<sub>8</sub>F<sub>17</sub>CH<sub>2</sub>CH<sub>2</sub>OH)  

Formation of C7F15COOH (PFOA) and other Perfluorocarboxylic acids (PFCAs) during the Atmospheric Oxidation of 8:2 Fluorotelomer Alcohol (n-C8F17CH2CH2OH)

T. J. Wallington, M. D. Hurley, J. Xia, D. J. Wuebbles, S. Sillman, A. Ito, J. E. Penner, D. A. Ellis4, J. Martin, S. A. Mabury, O. J. Nielsen, M. P. Sulbaek Andersen Ford, University of Michigan, Illinois, Copenhagen, and Toronto

Calculations using a 3-D global atmospheric chemistry model (IMPACT) indicate that n-C8F17CH2CH2OH (widely used in industrial and consumer products) degrades in the atmosphere to give perfluorooctanoic acid (PFOA) and other perfluorocarboxylic acids (PFCAs).  PFOA is persistent, bioaccumulative, and potentially toxic.  Molar yields of PFOA depend on location and season, are in the range 1-10%, and are of the correct order of magnitude to explain the observed levels in Arctic fauna.  Fluorotelomer alcohols such as n -C8F17CH2CH2OH appear to be a significant global source of persistent bioaccumulative perfluorocarboxylic acid pollution.  This is the first modeling study of the atmospheric chemistry of a fluorotelomer alcohol.

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Redox Tunable Defects in Colloidal Photonic Crystals  

Redox Tunable Defects in Colloidal Photonic Crystals

Friederike Fleischhaker, Andre C. Arsenault, Zhuo Wang, Vladimir Kitaev, Frank C. Peiris, Georg von Freymann, Ian Manners, Rudolf Zentel and Geoffrey A. Ozin, Advanced Materials 2005 (20), 2455.

Redox Tunable Defects in Colloidal Photonic Crystals Friederike Fleischhaker, Andre C. Arsenault, Zhuo Wang, Vladimir Kitaev, Frank C. Peiris, Georg von Freymann, Ian Manners, Rudolf Zentel and Geoffrey A. Ozin, Advanced Materials 2005 (20), 2455. Reversible tuning of an intragap transmitting state induced by redox cycling is accomplished using a redox-active polyferrocenylsilane polyelectrolyte multilayer planar defect embedded in a colloidal photonic crystal (CPC). The wavelength position of the defect state can be changed by changing the oxidation state of the ferrocene moieties in the polymer backbone. This could find applications in electrochemically tunable microcavities, and - if light emitters are incorporated - electrochemically tunable CPC-based laser sources.

Date: 2005-11-01

Analyzing the 3D Structure of Human Carbonic Anhydrase II and Its Mutants Using Deep View and the Protein Data Bank  

Analyzing the 3D Structure of Human Carbonic Anhydrase II and Its Mutants Using Deep View and the Protein Data Bank

Noam J. Ship and Deborah B. Zamble

A lab was designed to teach biological chemistry students to critically analyze the 3D structure of a protein. The enzyme studied was human carbonic anhydrase (II) and students also examined mutants and protein bound to a variety of ligands, metals, and inhibitors. The coordinate files for each protein are downloaded by the students from the Protein Data Bank. The structure is viewed and manipulated with the public-domain molecular-viewing software Deep View. Students learn how to interpret Ramachandran plots, study familial homology, make virtual mutations, compare structures, analyze structural details, and produce stunning 3D images. The lab runs on personal computers with Internet access and requires minimal to no supervision. This lab can be used as an independent project or as part of a more comprehensive set of experiments, and it can be adapted to the study of other biomolecules.

Date: 2005-12-01

Aziridines and Epoxides in Organic Synthesis  

Aziridines and Epoxides in Organic Synthesis

Yudin, A. K.

Aziridines and epoxides are among the most widely used intermediates in organic synthesis, acting as precursors to complex molecules due to the strain incorporated in their skeletons. Besides their importance as reactive intermediates, many biologically active compounds also contain these three-membered rings. Filling a gap in the literature, this clearly structured book presents the much-needed information in a compact and concise way.

Date: 2005-10-01

Nanochemistry: A Chemical Approach to Nanomaterials  

Nanochemistry: A Chemical Approach to Nanomaterials

G Ozin, A Arsenault; University of Toronto, Canada

From the author of the highly cited paper "Nanochemistry: Synthesis in Diminishing Dimensions" Advanced Materials 1992, 4, 612-649, comes the first teaching textbook on the subject entitled "Nanochemistry: A Chemical Approach to Nanomaterials". The textbook is published by The Royal Society of Chemistry and is co-authored by Geoffrey A. Ozin and Andre Arsenault, Materials Chemistry Research Group, Department of Chemistry, University of Toronto. It is scheduled to appear in July 2005. Details of the book can be found on the following web sites:

This is the first textbook for teaching Nanochemistry and adopts an interdisciplinary and comprehensive approach to the subject. It presents a basic chemical strategy for making nanomaterials and describes some of the principles of materials self-assembly over "all" scales. It demonstrates how nanometer and micrometer scale building blocks, with a wide range of shapes, compositions and surface functionalities, can be coerced through chemistry to organize spontaneously into unprecedented structures, which can serve as tailored functional materials. Suggestions of new ways to tackle research problems in Nanoscience and speculations on how to think about assembling the future of Nanotechnology are given.

Designed for teaching the underpinnings of Nanoscience through the eye of the materials chemist and crosscutting the traditional boundaries of chemistry and physics, materials science and engineering, biology and medicine, this twelve-chapter book will appeal to graduate and advanced undergraduate students. It has however been written so that it can be easily be adapted for introducing the principles of Nanochemistry to undergraduates in their freshman to higher years. It is well illustrated with graphical representations of the synthesis, structure and form of nanomaterials, and contains problem sets as well as other pedagogical features such as further reading, case studies and a comprehensive bibliography. It also presents a blueprint of experiments for NanoLab, an undergraduate laboratory that gives a hands-on experience to the student wishing to appreciate the practical side of Nanochemistry, as described in each chapter of the book. The Contents of the book follows the order: Preface - In the Beginning there was Nano; Nanochemistry Basics; Chemical Patterning and Lithography; Layer-By-Layer Self-Assembly; Nanocontact Printing and Writing; Nanorod, Nanotube, Nanowire Self-Assembly; Nanocluster Self-Assembly; Microspheres - Colours from the Beaker; Microporous and Mesoporous Materials; Self-Assembling Block Copolymers; Biomaterials and Bioinspiration; Self-Assembly of Large Building Blocks; Nano and Beyond; Nanochemistry and Nanolabs; Appendices, Subject Index.



Date: 2005-07-01

Microfluidics: From Dynamic Lattices to Periodic Arrays of Polymer Disks  

Microfluidics: From Dynamic Lattices to Periodic Arrays of Polymer Disks

Minseok Seo, Zhihong Nie, Shengqing Xu, Patrick C. Lewis, and Eugenia Kumacheva

Illustration by Eugenia Kumacheva. We used a microfluidic flow-focusing device to generate highly monodisperse discoid droplets of oil or monomer liquid. The droplets were assembled into two-dimensional gliding lattices with a high degree of order and symmetry by coupling of flow and confinement. Following increase in total volume of droplets produced per unit time, the lattices underwent a transition from a close-packed array of circular disks to the array of hexagonal disks. In situ photopolymerization of the monomer droplets produced highly periodic arrays of solidified polymer disks. For more information see "Microfluidics: From Dynamic Lattices to Periodic Arrays of Polymer Disks" by Minseok Seo, Zhihong Nie, Shengqing Xu, Patrick C. Lewis, and Eugenia Kumacheva, on pages 4773-4775 of this issue. Copyright 2005 American Chemical Society.

Date: 2005-05-01

Photon echo studies of biexcitons and coherences in colloidal CdSe quantum dots  

Photon echo studies of biexcitons and coherences in colloidal CdSe quantum dots

Anne E. Colonna, Xiujuan Yang, and Gregory D. Scholes*
Lash-Miller Chemical Laboratories, University of Toronto, 80 St. George St., Toronto, Ontario, M5S 3H6, Canada
phys. stat. sol. (b) 242, No. 5, 990Š1000 (2005)


Nonlinear optical properties of colloidal quantum dots are studied to elucidate the significance and nature of many-body effects. Two-pulse photon echo studies of nanocrystalline CdSe quantum dots are reported for samples dispersed in a poly(butylmethacrylate) film (4.4 K). Oscillations are observed in the experimental data that are attributed to 1S3/2 1Se -> 2S3/2 1Se biexciton cohererences. Signals are simulated using a phenomenological model based on the many-body description of the dynamics (the average polarization model). It is found that the electronic coherences and the nonlinear response originating from biexciton source terms are important, but their manifestation in the photon echo signals is strongly influenced by the interplay between homogeneous and inhomogeneous line broadening.

Date: 2005-03-01

Colloidal Crystal Capillary Columns - Towards Optical Chromatography  

Colloidal Crystal Capillary Columns - Towards Optical Chromatography

U. Kamp, V. Kitaev, G. von Freymann, G. A. Ozin, S. A. Mabury Advanced Materials 2005(4), 438 Published Online: 5 Jan 2005 DOI: 10.1002/adma.200400020

ABSTRACT: The cover illustration, designed by Ludovico Cademartiri, is an artistic rendering of novel micro- and nanobore chromatographic columns. The three-dimensional periodic arrangement of the building blocks, solid spheres or air-spheres, constituting the chromatographic stationary phase allows wavelength-selective interaction of electromagnetic radiation with the stationary phase. The photonic stop-band responsible for the structural color of the column is monitored spectroscopically and shifts of its wavelength, generated by minute refractive index changes within a mobile phase (here represented by alkane homologues), can be immediately detected at any point along and around the column due to the exceptional structural uniformity.

Date: 2005-02-01

Evolution of Nanocrystallinity in Periodic Mesoporous Anatase Thin Films  

Evolution of Nanocrystallinity in Periodic Mesoporous Anatase Thin Films

Sung Yeun Choi, Marc Mamak, Scott Speakman, Naveen Chopra, Geoffrey A. Ozin Small 2005(2), 226

Herein we report the first kinetic study of the intrachannel wall phasetransition of amorphous titania to nanocrystalline anatase for periodic mesoporous titania thin films, monitored by time-resolved in situ hightemperature X-ray diffraction. Structural transformations associated with the phase transition are further probed by high-resolution scanning electron microscopy and transmission electron microscopy. The model found to be most consistent with the kinetic data involves 1D diffusioncontrolled growth of nanocrystalline anatase within the spatial confines of the channel walls of the mesostructure. The observation of anisotropic, rod-shaped anatase nanocrystals preferentially aligned along the channel axis implies that the framework of the liquid-crystal-templated mesostructure guides the crystal growth.

Date: 2005-01-01

An Atomic-Level View of Melting Using Femtosecond Electron Diffraction  

An Atomic-Level View of Melting Using Femtosecond Electron Diffraction

Bradley J. Siwick, Jason R. Dwyer, Robert E. Jordan, R. J. Dwayne Miller

We used 600-femtosecond electron pulses to study the structural evolution of aluminum as it underwent an ultrafast laserinduced solid-liquid phase transition. Real-time observations showed the loss of long-range order that was present in the crystalline phase and the emergence of the liquid structure where only short-range atomic correlations were present; this transition occurred in 3.5picoseconds for thin-film aluminum with an excitation fluence of 70 millijoules per square centimeter. The sensitivity and time resolution were sufficient to capture the time-dependent pair correlation function as the system evolved from the solid to the liquid state. These observations provide an atomic-level description of the melting process, in which the dynamics are best understood as a thermal phase transition under strongly driven conditions.

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Synthetic self-propelled nanorotors  

Synthetic self-propelled nanorotors

Sebastien Fournier-Bidoz, Andre C. Arsenault, Ian Manners* and Geoffrey A. Ozin*

Self-powered completely synthetic nanorotors have been prepared from barcoded gold–nickel nanorods having the gold end anchored to the surface of a silicon wafer; constant velocity circular movements are observed when hydrogen peroxide fuel is catalytically decomposed to oxygen at the unattached nickel end of the nanorod.

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