Epr Spectra of ￥á-1,2,3-[HnPV(￥3)￥′2W9O40](7-n)-(n = 1, 2 or 3). The Effects of Protonation on the Electron Transfer Rate

摘要

The solution epr spectra of メ-1,2,3-[HnPV(コ)ゴ 2W9O40](7-n)- were measured at various pH and three protonated species have been identified. The spectrum of H3PV(コ)ゴ2 consisting of 8 lines indicates that the V-OH-V bridge prevents effectively the electron transfer between the vanadium atoms. The spectrum of HPV(コ)V2 consisting of 15 lines can be interpreted by assuming that the electron is hopping fast between the two vanadium atoms in the V-O-V sequence. The multi-line spectrum of HPV(コ)V2 is interpreted as a poorly resolved 43-line spectrum which originates from the electron hopping among the three vanadium atoms with the forward and backward transition probabilities of 4:1 in the OH-V-O-V sequence.