Organotransition Metal Chemistry and Catalysis

点击翻译按钮获取中文摘要

Our research program involves investigations of the chemistry of and catalysis by organotransition metal compounds, and is an extension of a very long term program in basic and applied research which goes back over 40 years. My 2015 DG application describes three important, related research Themes which, as they are significantly advanced over the next five years, will greatly contribute to potential industrial applications of metal catalysis in Canada. Theme 1. Elusive intermediates in alkene polymerization catalysis. Prior to our work, researchers had had very little success in detecting several types of short-lived intermediate species in metallocene catalyzed alkene polymerization reactions. We solved this problem using alkenes which can coordinate but cannot, for steric reasons, undergo more than one insertion reaction. As a result, we show that we can use NMR to observe not only unusual alkyl alkene species but also unprecedented types of agostic complexes. This is a proposal to explore complexes of the types [Cp2MMe(alkene)]+ (M = Zr, Hf) for which we have fascinating preliminary results in hand. The results will contribute greatly to our understanding of this very important class of industrial catalysts. Theme 2. Catalysis of cross-coupling reactions by nickel. Nickel has important advantages over the normally used palladium for cross-coupling catalysis because, in addition to its lower cost, nickel works with many more types of substrates than does palladium. This proposal extends our ongoing program on the use of palladium-based catalysts and involves a study of several types of nickel compounds for their catalytic activities. Success will provide opportunities to systematically tailor catalysts by modifying the ligands in order to to effect asymmetric and stereoconvergent cross-coupling reactions. The results, in addition to adding much to basic knowledge of catalytic processes, will be of obvious potential benefit to Canada's pharmaceutical industry. Theme 3. Coordination chemistry of phosphonium indenylides (PHINs). This largely unexplored class of aromatic ligands is of special interest because they bind to transition metals to form planar chiral complexes which are configurationally stable; thus they may well serve as excellent asymmetric catalysts for reactions of prochiral substrates because the catalysts will be rigidly chiral directly at the metal rather than at the periphery of a ligand as is normally the case. This proposal describes research on planar chiral compounds of several metals, chosen because their complexes with other ligands catalyze a very wide range of important catalytic reactions. As is the case with Theme 2, successful results will be of obvious potential benefit to Canada's pharmaceutical industry. Our program will continue, as it has for many years, to train four to eight undergraduate, graduate and postdoctoral researchers per year.