Robert G. Bergman
Research in the Bergman group is focused on stoichiometric and catalytic organometallic reactions that take place in homogeneous solution, with the goal of developing new processes and understanding their mechanisms. Density functional theory is being used to supplement understanding obtained from mechanistic experiments and help to determine the direction of new experimental work. Current efforts are focused on reactions that both cleave and form bonds between carbon and other elements, such as hydrogen, oxygen and nitrogen. One major effort is directed toward carbon-hydrogen (C-H) bond activation reactions. This involves the development and study of metal complexes capable of undergoing intermolecular oxidative addition with the normally inert C-H bonds in alkanes and other organic molecules. This process holds potential for converting methane and other hydrocarbons into useful functionalized organic molecules. Low-valent late transition metals, such as iridium(I) and rhodium(I), as well as higher-valent systems based on iridium(III), have been found to undergo these reactions. Experiments using conventional and flash kinetic studies have helped to elucidate the mechanisms of these reactions and identify several very short-lived intermediates. Recent efforts have also led to the development of catalytic C-H activation reactions applicable to problems in organic synthesis, such as efficient cyclization reactions.
A second major area of investigation involves the study of organometallic complexes having metal-oxygen, -nitrogen and -sulfur bonds to obtain information about the mechanisms of metal-mediated oxidation, amination and desulfurization processes. Recent efforts in this area have yielded early transition metal complexes capable of carrying out cycloaddition reactions between metal-nitrogen multiple bonds and substituted allenes with high levels of enantioselection, and the discovery of complexes with exceptionally basic nitrogen ligands. These reactions are being applied to the development of efficient catalytic carbon-nitrogen bond-forming processes such as carbon-carbon multiple bond hydroamination reactions.