Event

Title Small Ligands Behaving Badly: Redox Non-innocence in Earth-Abundant 3d Metal Catalysts

Abstract “Green” replacements for platinum group metals (PGMs) have been of considerable interest in the catalysis community. Within the larger field of sustainable catalysis, the use of potentially redox non-innocent (RNI) ligands in conjunction with Earth-abundant 3d metals (which are, of course, more prone to 1-e- or radical chemistry vis-à-vis their 4d and 5d congeners) to mimic the even-e- chemistry of PGM catalytic cycles has been the intensely studied by experimentalists. Our group has sought to develop computational modeling tools and the intellectual advances necessary to understand (and eventually design) catalyst systems whereby a RNI ligand and a 3d metal may be synergized to deliver 2 e- to a metal-ligand active site for the purposes of productive catalytic reactions such as the activation and functionalization of strong chemical bonds such as aliphatic C—H or olefinic C=C bonds. In addition to elaborately constructed (typically conjugated) organic supporting ligand scaffolds, our most recent research, in concert with experimental efforts, shows evidence of RNI behavior – not only in terms of formal oxidation states that do not correspond to those expected by simple bonding principles but that change in redox poise during the course of a reaction – in unexpected chemical moieties including multiply bonded ligands (e.g., imide/imidyl and oxide/oxyl) and even saturated, ring-strained hydrocarbyls (such as 1-norbornyl). This talk will provide an overview of our past and current work in this area with some thoughts on future directions.

Inquiries please contact Rosa M. Vargas rvargas@sas.upenn.edu