116211-35-9Relevant articles and documents
Selectivity control by axial ligand modification in manganese porphyrin catalyzed oxidations
Nappa, Mario J.,McKinney, Ronald J.
, p. 3740 - 3745 (2008/10/08)
The addition of tin Lewis acids, Ph3SnO2C8F15 (1a) and Ph3SnO3SC6F13 (1b), increases the reactivity and reduces the radical character in hydrocarbon oxidation reactions using iodosylbenzene and manganese porphyrins, Mn(TPP)OAc and Mn(TpyP)OAc,1 by substitution of -OAc with the perfluoro anion to make Mn(porphyrin)O2C8F15 or Mn(porphyrin)O3SC6F13. This increase in reactivity and reduction of radical character are explained by using semiempirical molecular orbital calculations, which show the effects of anion exchange on the electronic structure of O=MnV(porphyrin)+X-. When -OAc is replaced by a less coordinating axial ligand, the oxomanganese intermediate has less oxy radical character. Our cyclohexane, cyclohexene, norcarane, and cis-stilbene oxidation results as well as kinetic isotope effects are consistent with the oxygen atom insertion into C-H and C-C bonds becoming more concerted in nature. In addition to their role in anion substitution, these tin complexes function as radical inhibitors to further reduce the radical character of oxidation reactions using manganese porphyrins.
