Proton-Coupled Electron Transfer from Tyrosine: A Strong Rate Dependence on Intramolecular Proton Transfer Distance
2011; American Chemical Society; Volume: 133; Issue: 34 Linguagem: Inglês
10.1021/ja203483j
ISSN1943-2984
AutoresMing‐Tian Zhang, Tania Irebo, Olof Johansson, Leif Hammarström,
Tópico(s)Metalloenzymes and iron-sulfur proteins
ResumoProton-coupled electron transfer (PCET) was examined in a series of biomimetic, covalently linked RuII(bpy)3–tyrosine complexes where the phenolic proton was H-bonded to an internal base (a benzimidazyl or pyridyl group). Photooxidation in laser flash/quench experiments generated the RuIII species, which triggered long-range electron transfer from the tyrosine group concerted with short-range proton transfer to the base. The results give an experimental demonstration of the strong dependence of the rate constant and kinetic isotope effect for this intramolecular PCET reaction on the effective proton transfer distance, as reflected by the experimentally determined proton donor–acceptor distance.
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