A Manganese(V)-Oxo pi-Cation Radical Complex: Influence of One-Electron Oxidation on Oxygen-Atom Transfer

作者:Prokop Katharine A; Neu Heather M; de Visser Sam P*; Goldberg David P
来源:Journal of the American Chemical Society, 2011, 133(40): 15874-15877.
DOI:10.1021/ja2066237

摘要

One-electron oxidation of Mn(v)-oxo corrolazine 2 affords 2(+), the first example of a Mn(v)(O) pi-cation radical porphyrinoid complex, which was characterized by UV-vis, EPR, LDI-MS, and DFT methods. Access to 2 and 2(+) allowed for a direct comparison of their reactivities in oxygen-atom transfer (OAT) reactions. Both complexes are capable of OAT to PPh(3) and RSR substrates, and 2(+) was found to be a more potent oxidant than 2. Analysis of rate constants and activation parameters, together with DFT calculations, points to a concerted OAT mechanism for 2(+) and 2 and indicates that the greater electrophilicity of 2(+) likely plays a dominant role in enhancing its reactivity. These results are relevant to comparisons between Compound I and Compound II in heme enzymes.

  • 出版日期2011-10-12