Student Hosted Colloquia: Professor Bob Bergman (Host: Katherine Walker)
"The Application of Physical Organic Methods to the Investigation of Organometallic Reaction Mechanisms"
About the Seminar
The modern era of organotransition metal chemistry arguably began with the synthesis and characterization of ferrocene in the early 1950’s. For the following twenty years, the field grew substantially in both industrial and academic laboratories. While industry efforts relied on a trial-and-error approach to develop and improve catalysts, academic investigators focused on the structural characterization of new organotransition metal complexes and descriptive studies of their reactions. Although many unusual transformations were discovered during this period, the mechanisms of most of these reactions were poorly understood. In the late 1960’s and 1970’s, a few investigators began to address this dearth of mechanistic understanding. Inorganic chemists who were experts in kinetic investigations afforded one avenue towards gaining insights into organometallic reaction mechanisms. Yet another path was taken by young chemists trained in the physical organic tradition of people like Paul Bartlett, William Doering, Saul Winstein and Jerome Berson. These groups, including mine at Caltech and subsequently UC Berkeley, began to tackle the problem of both discovering new organometallic chemistry and unraveling the mechanisms of these reactions. During the course of our investigations, we made inroads into the discovery and understanding of processes such as alkyne cyclization, nitric oxide migratory insertion and addition of metal nitrosyl complexes to alkenes, organometallic cluster complex formation, alkyne hydroamination, and carbon-hydrogen bond activation. This lecture will provide a personal overview of this work and a historical perspective of our contributions to mechanistic understanding in organotransition metal chemistry during the past 40 years.
About the Speaker
Robert G. Bergman completed his undergraduate studies in chemistry at Carleton College in 1963 and received his Ph.D. at the University of Wisconsin in 1966 under the direction of Jerome A. Berson. Bergman spent 1966-67 as a postdoctoral fellow in Ronald Breslow’s laboratories at Columbia, and following that began his independent career at the California Institute of Technology. He accepted an appointment as professor of chemistry at the University of California, Berkeley, in July 1977 and moved his research group to Berkeley a year later. He was appointed Gerald E.K. Branch Distinguished Professor in 2002 and G. E. K. Branch Distinguished Professor Emeritus in 2016.
Bergman was trained as an organic chemist and spent the first part of his independent career studying reaction mechanisms that involve unusually reactive molecules, such as 1,3-diradicals and vinyl cations. In 1972 he discovered a transformation of ene-diynes, later identified by others as a crucial DNA-cleaving reaction in several antibiotics that bind to nucleic acids. In the mid- 1970’s Bergman’s research broadened to include organometallic chemistry, which led to contributions to the development and study of the reaction mechanisms of migratory insertion and oxidative addition reactions, the chemistry of new dinuclear complexes, and the investigation of organometallic compounds having metal-oxygen and -nitrogen bonds. He is best known for his discovery of the first soluble organometallic complexes that undergo intermolecular insertion of transition metals into the carbon-hydrogen bonds of alkanes. Most recently he has been involved in collaborative studies with colleagues at Berkeley and elsewhere that include applications of catalytic C-H activation reactions in organic synthesis, reactions catalyzed by supramolecular systems, and the chemistry of complexes bearing metal-heteroatom single and multiple bonds.
Bergman has received numerous national awards, including the Arthur C. Cope Award of the American Chemical Society, the Welch Foundation Award in Chemistry, and the Wolf Prize in Chemistry. He has co-authored more than 500 publications in peer-reviewed journals. His selection as the recipient of the ACS James Flack Norris Award in Physical Organic Chemistry recognized him for his early work in that field; his later reception of the ACS Award in Organometallic Chemistry, for his pioneering work in the application of physical organic methods to the study of organometallic reaction mechanisms, emphasizes how many of Bergman’s achievements came in the interdisciplinary area between organic and inorganic chemistry, and attests to the wide impact that his research has had.