652133-44-3Relevant academic research and scientific papers
A manganese(V)-oxo π-cation radical complex: Influence of one-electron oxidation on oxygen-atom transfer
Prokop, Katharine A.,Neu, Heather M.,De Visser, Sam P.,Goldberg, David P.
, p. 15874 - 15877 (2011)
One-electron oxidation of MnV-oxo corrolazine 2 affords 2 +, the first example of a MnV(O) π-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 PPh3 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.
Dramatic influence of an anionic donor on the oxygen-atom transfer reactivity of a Mnv-Oxo complex
Neu, Heather M.,Quesne, Matthew G.,Yang, Tzuhsiung,Prokop-Prigge, Katharine A.,Lancaster, Kyle M.,Donohoe, James,DeBeer, Serena,De Visser, Sam P.,Goldberg, David P.
, p. 14584 - 14588 (2014)
Addition of an anionic donor to an MnV(O) porphyrinoid complex causes a dramatic increase in 2-electron oxygen-atom-transfer (OAT) chemistry. The 6-coordinate [MnV(O)(TBP8 Cz)(CN)]- was generated from addition of Bu4N + CN- to the 5-coordinate MnV(O) precursor. The cyanide-ligated complex was characterized for the first time by Mn K-edge X-ray absorption spectroscopy (XAS) and gives Mn-O = 1.53 ?, Mn-CN = 2.21 ?. In combination with computational studies these distances were shown to correlate with a singlet ground state. Reaction of the CN- complex with thioethers results in OAT to give the corresponding sulfoxide and a 2e--reduced MnIII(CN) - complex. Kinetic measurements reveal a dramatic rate enhancement for OAT of approximately 24 000-fold versus the same reaction for the parent 5-coordinate complex. An Eyring analysis gives ΔH± = 14 kcalmol-1, ΔS± = -10 cal mol-1 K-1 . Computational studies fully support the structures, spin states, and relative reactivity of the 5- and 6-coordinate MnV(O) complexes.
