Research Overview
Synthesis, Catalysis, and Innovation
The growing drive to develop more economical and sustainable practices has become a major influence on modern chemists. However, many commercial processes continue to utilize catalysts based on platinum group metals, which are expensive, toxic, and of increasingly limited supply. In our group, we use inorganic and organometallic chemistry, supported by theoretical computations, to develop inexpensive and sustainable catalysts for various chemical transformations.
Sustainable Energy Solutions
One area that we investigate is the catalytic activation of small molecules for energy storage. While these transformations are exceedingly difficult, we can take inspiration from nature, where enzymes catalyze these reactions using earth-abundant metals. As such, we adapt key concepts from biological systems in order to develop sustainable artificial catalysts using calixpyrrole ligand scaffolds. In particular, we utilize directing groups in the secondary coordination sphere to enable proton-coupled electron transfer processes, which increase catalytic rates and stability.
Biomimetic Catalyst Design
While the calixpyrrole systems with pendent groups are being investigated as small molecule activation catalysts, they also present a rare opportunity to generate multimetallic systems with chemically distinct coordination environments. These unsymmetric systems are very desirable because they allow the formation of hetero-multimetallic species, which more closely mimic enzyme active sites. These types of complexes are traditionally very challenging to access, requiring multi-step, poor yielding syntheses to generate ligand architectures with marginally different binding environments. A key distinguishing factor for the calixpyrrole systems is the ease with which the unsymmetric ligands can be generated using straightforward Schiff-base chemistry.
Olefin Metathesis Catalysts
Another area that we explore is the efficient and selective formation of carbon-carbon double bonds through olefin metathesis. Traditional olefin metathesis catalysts developed by the Schrock and Grubbs groups utilize group VI metals (tungsten and molybdenum) and ruthenium, respectively. Our group focuses on developing olefin metathesis catalysts that exhibit the best characteristics of both of these systems; high activity and selectivity utilizing modular ligand frameworks, as well as functional group tolerance using late transition metal centres. The use of phosphinimine ligands is especially key in imparting catalytic activities approaching the diffusion rate limit.
