Professor Jim Mayer of Yale University

Professor Jim Mayer of Yale University will present

"Adventures in Proton-Coupled Electron Transfer: From Hydrogen Atom Transfer to Separated Electrons and Protons to Nanocystals"

on February 21, 2018 at 4:10 PM in Neville Hall, Room 3.

 

Abstract:

A wide range of chemical processes proceed by proton-coupled electron transfer (PCET), including combustion, enzymatic reactions, and redox processes at oxide surfaces. This presentation will begin with fundamental studies of single reaction steps that involve transfer of one proton and one electron. Some of these reactions ‘look like’ transfer of a hydrogen atom, while in other reactions the electron and proton are quite separated in the reactants or products. In the upper drawing below, for instance, cleavage of a C–H bond is achieved by removal of an electron from the bond to an oxidant and transfer of the proton to a nearby carboxylate. This is the first example of cleavage of a C–H bond cleavage by such a multiple-site concerted proton-electron transfer (MS-CPET). The rate constants for many of these reactions can be understood using a version of Marcus Theory, which shows the commonality of organic and transition metal H-atom transfer reactions. PCET is also an under-appreciated aspect of the reactivity of redox reactions at oxide materials, such as colloidal ZnO, TiO2, and CeO2 nanocrystals. For instance, the chemical reaction of reduced ZnO and TiO2 nanocrystals with the nitroxyl radical proceeds by transfer of e– and H+ (a hydrogen atom), as shown below.