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Ian Manners

Ian Manners

Academic Title: Professor (Status Only)

Affiliation: School of Chemistry, Bristol University

Email:

Research Homepage: http://www.inchm.bris.ac.uk/people/manners/home.html

Research

Our group has very broad research interests which revolve around the molecular, polymer, and materials chemistry of inorganic elements. Much of the work in our group is inherently interdisciplinary in nature and accommodates students with interests in all areas of chemistry. The research provides students with a versatile training in small molecule, polymer, and materials synthesis and characterization techniques. Further details are provided at our research group homepage (see link above).

1. Synthesis, Properties, and Applications of Polymers Based on Main Group and Transition Elements

As a consequence of their favorable material properties and ease of fabrication, synthetic polymers have found a tremendous range of applications in the world around us and their use is expected to grow even more rapidly in the future. With the discovery of polymers which possess unusual electronic and optical characteristics (e.g. electronic conductivity, electroluminescence, non-linear optical properties) end-uses now include a multitude of high-tech device-oriented applications. Remarkably however, although the chemical structure of a polymer is known to profoundly affect the properties obtained, virtually all of the synthetic polymers created to date are "organic" and have backbones mainly constructed from carbon atoms. Nevertheless, studies of the few known classes of linear inorganic polymers such as silicones, polyphosphazenes, and polysilanes, have shown that they possess many unusual and useful properties which are often difficult or impossible to achieve with conventional organic systems. In our group we are attempting to attack the synthetic challenge of joining atoms of inorganic elements together into long chains mainly by exploring the use of ring-opening polymerization (ROP) and transition metal-catalyzed polymerization strategies.

The main driving force for ROP reactions is the presence of ring-strain in the cyclic monomer. This leads us to design and synthesize strained rings constructed from main group elements and/or transition metals and generates a fundamental need to understand the structure, bonding, and possible mechanisms of polymerization of such species. If ROP is successful, we then explore the properties and applications of the new macromolecules and our more applied work involves, for example, the development of novel elastomers, protective coatings, biocomposites, blends, photoconductors, photonic band gap materials, lithographic templates, superlattices, sensors, and nanomaterials. These projects often involve collaboration with other academic scientists and with industry.

2. Inorganic Block Copolymers, Self-Assembly, Supramolecular Chemistry, and Nanoscience

We are particularly interested in developing controlled synthetic routes to well-defined polymers with main group or transition metals in the backbone. One class of polymers discovered by our group which are currently under close scrutiny are the polyferrocenylsilanes which possess backbones of alternating ferrocene and organosilane units. We have developed living polymerization routes to polyferrocenylsilane block copolymers which exhibit remarkable self-assembly characteristics in the solid state and in solution. We and our collaborators are investigating a range of potential applications of the resulting thin films and micelles which possess nanoscopic metal-rich domains. Nanoscience applications currently under investigation include uses as nanowires, nanotubes, and as magnetic dot precursors.

3. Applications of Metal Catalysis and other Novel Synthetic Methodologies in Inorganic Chemistry

The development of transition metal-catalyzed reactions in the latter half of the 20th century revolutionized synthetic organic chemistry both at the molecular and macromolecular level. In contrast, synthetic methodologies used to create frameworks based on inorganic elements are still generally rather haphazard and are of very limited scope; often the only predictable pathways rely on salt metathesis processes. We have been very interested in applying the concept of metal catalysis to the development of rings, chains, cages, and polymers based on skeletons of atoms of inorganic elements. Previous work has strongly suggested that stable catenated structures with useful properties are highly likely if efficient synthetic access can be devised. Recently we have discovered metal-catalyzed processes for the formation of boron-phosphorus and boron-nitrogen bonds. This has allowed us to access a range of interesting new rings, chains, and macromolecules based on Group 13-Group 15 element frameworks. We have also developed novel synthetic approaches to inorganic heterocycles termed "skeletal substitution" reactions in which a ring atom (often boron) is replaced in a controlled reaction at room temperature. This chemistry may ultimately be useful for the preparation of new catalysts or monomers for ROP.

4. Chemistry and Applications of Reactive Inorganic Molecules

Our group is also very interested in the chemistry and materials applications of reactive inorganic molecules. Such species are of fundamental interest and also as polymerization monomers, and as reactive intermediates in polymerization reactions. In the latter case in depth studies can provide important and much needed insight into polymerization mechanisms. Recent work has involved investigations of hypercoordinate silicon species, low coordinate silicon cations, phosphoranimines (with P=N bonds), and heterocycles containing cationic sulfur(VI) centers.

Selected Publications

See Research Homepage