Hydrogen Atom or Proton Coupled Electron Transfer? C–H Bond Activation by Transition-Metal Oxides

Authors:
Publisher website
Google Scholar
Abstract
The C-H bond activation in oxidative dehydrogenation of propane by hetero-bimetallic oxide clusters (first row transition metals), deposited on the zirconium oxide node of the NU-1000 metal organic framework, was investigated by multireference wave function theory. The redox- active part of the systems studied has composition (CoO)(MO)(OH)2 with M= Ti, Mn, Fe, Co, Ni, Cu, Zn. In this series, the energy of H transfer from propane to the metal oxide (DE) varies from -26 kcal/mol for M=Cu, Zn to 85 kcal/mol for M=Ti. This is accompanied by a change in the mechanism from hydrogen atom transfer, M2+(dn) OŸ−● M2+(dn) OH− , for M=Cu, Zn to proton coupled electron transfer, Mm+(dn) O2− -> M(m-1)+(dn+1) OH−, for M=Ni, Co, Fe, Mn, Ti. Whereas for M=Ni (DE = -13 kcal/mol) Ni+III is reduced to Ni+II, for M=Co, Fe, Mn (DE = 1, 10, 6 kcal/mol, respectively) it is Co+III that is reduced to Co+II, For M=Ti, Ti maintains its +IV oxidation state and Co+II is reduced to Co+I.
Funding Information
  • Basic Energy Sciences (DE-SC0012702)
  • Deutsche Forschungsgemeinschaft
  • Verband der Chemischen Industrie

This publication has 44 references indexed in Scilit: