Sustainability is one of the major challenges facing modern society, and modern chemistry. Merely to maintain current standards of living, we must learn to do more with less: we must husband our resources; we must curb our profligate use of energy and fossil reserves; and we must learn better how to transform wastes into commodities. My research in molecular catalysis is directed at the discovery of energy- and resource-frugal ways to build the molecules and materials that enable the advanced technologies of the 21st century. A snapshot of selected projects and publications appears below.

Olefin Metathesis

Olefin metathesis is one of the most powerful methods in current use for the construction of new carbon-carbon bonds. However, 20 years after the discovery of "robust" metathesis catalysts based on ruthenium (the breakthrough discovery that resulted in real-world use of the methodology by organic chemists), and five years after the Nobel Prize for olefin metathesis, industrial applications to organic synthesis remain astonishingly limited. Our work in this highly competitive area has focused on understanding the factors that limit selectivity in ring-closing metathesis (RCM, one of the major synthetic applications of the methodology) and enyne metathesis, in delineating the parameters that limit the lifetimes of the dominant ruthenium catalysts, and using these insights to develop new methodologies or catalysts to aid industrial uptake. Collaborative work takes a "mechanistic engineering" approach to implementation of RCM in industrial flow chemistry.

Current projects focus on controlling stereoselectivity in Ru-catalyzed metathesis; metathesis of multiple bonds; use of new tools to assay catalyst longevity and deactivation under actual operating conditions; and new opportunities in sustainable metathesis (see next).



• Why use ethylene in enyne metathesis?    JACS 2011, 133, 15918
• Beyond the cauldron: Designing reactors for RCM    Chem. Eur. J. 2010, 16, 11720
• Ring-closing metathesis doesn't happen how you think    JACS 2007, 129, 1024
                                                                                       Chem. Rev. 2009, 109, 3783

Metathesis and Sustainability

Metathesis is likely to emerge as core technology for sustainable practices in the coming decade. With a 30% cut in fossil-fuel dependence by 2021 targeted as a US national-security goal, Canadian "waste" biomass represents a strategic resource that can be tapped via forefront methodologies in olefin metathesis. Likewise abundant, and in some cases more accessible, resources are found in tropical oils. Brazil Ð a Canadian federal-priority partner Ð has unsurpassed potential to contribute to high-value renewables through olefin metathesis, and to augment these via tandem catalysis, an area in which my group has made leading contributions. Collaborative work with Brazilian researchers (Minas Gerais, Rio de Janeiro) centers on these opportunities, and on producing highly-trained graduates with the skills to mobilize this enormous potential.

• Tandem catalysis: types & opportunities    Coord. Chem. Rev. 2004, 248, 2365
• Tandem catalysis in tissue engineering    Biomaterials 2009, 30, 5403
                                                               JACS 2007, 129, 4168

Harnessing Nitrogen

Conversion of N2 to ammonia consumes over 1% of the world's energy budget annually. Development of a robust catalyst capable of reducing (or indeed functionalizing) N2 under mild operating conditions thus has major implications for worldwide energy use. A major obstacle to date has been the lability of N2 as a ligand in the late metals. We recently discovered that electron-rich ruthenium complexes can strongly bind and activate N2. This opens up promising new directions in a long-studied area of major technological and societal importance.



• Unprecedentedly strong binding of N2 at a late-metal centre    Angew. Chem. Int. Ed. 2011, 50, 916

New Tools

We love powerful tools. Some we build; some we refine; some we collaborate with experts to use.



• Probing catalyst structure & function by MALDI-MS:    Angew. Chem. 2008, 47, 303 (VIP)
                                                                                   JACS 2011, 15918
                                                                                   JACS 2007, 1024
• High-throughput catalysis:    Organomet. 2011, 30, 36
• HT Kinetics:    Adv. Syn. Catal. 2008, 350, 2849
• Time-dependent DFT:    Organometallics 2009, 28, 5424 (with Serge Gorelsky, uOttawa)