UMR CNRS 6521, Chimie, Electrochimie Moléculaires et Chimie Analytique, Université de Bretagne Occidentale, UFR Sciences et Techniques, Cs 93837, 29238 Brest-Cedex 3, France.
Inorg Chem. 2011 Dec 19;50(24):12575-85. doi: 10.1021/ic201601q. Epub 2011 Nov 22.
The one-electron oxidation of the diiron complex [Fe(2)(CO)(4)(κ(2)-dppe)(μ-pdt)] (1) (dppe = Ph(2)PCH(2)CH(2)PPh(2); pdt = S(CH(2))(3)S) has been investigated in the absence and in the presence of P(OMe)(3), by both electrochemical and theoretical methods, to shed light on the mechanism and the location of the oxidatively induced structure change. While cyclic voltammetric experiments did not allow to discriminate between a two-step (EC) and a concerted, quasi-reversible (QR) process, density functional theory (DFT) calculations favor the first option. When P(OMe)(3) is present, the one-electron oxidation produces singly and doubly substituted cations, Fe(2)(CO)(4-n){P(OMe)(3)}(n)(κ(2)-dppe)(μ-pdt) (n = 1: 2(+); n = 2: 3(+)) following mechanisms that were investigated in detail by DFT. Although the most stable isomer of 1(+) and 2(+) (and 3(+)) show a rotated Fe(dppe) center, binding of P(OMe)(3) occurs at the neighboring iron center of both 1(+) and 2(+). The neutral compound 3 was obtained by controlled-potential reduction of the corresponding cation, while 2 was quantitatively produced by reaction of 3 with CO. The CO dependent conversion of 3 into 2 as well as the 2(+) ↔ 3(+) interconversion were examined by DFT.
[Fe(2)(CO)(4)(κ(2)-dppe)(μ-pdt)]（1）（dppe = Ph(2)PCH(2)CH(2)PPh(2)；pdt = S(CH(2))(3)S）的单电子氧化已在不存在和存在 P(OMe)(3)的情况下通过电化学和理论方法进行了研究，以阐明机制和氧化诱导结构变化的位置。虽然循环伏安实验无法区分两步（EC）和协同准可逆（QR）过程，但密度泛函理论（DFT）计算支持第一种选择。当存在 P(OMe)(3)时，单电子氧化产生单取代和双取代阳离子，Fe(2)(CO)(4-n){P(OMe)(3)}(n)(κ(2)-dppe)(μ-pdt)（n = 1：2(+)；n = 2：3(+)）遵循通过 DFT 详细研究的机制。尽管 1(+)和 2(+)（和 3(+)）的最稳定异构体显示出旋转的 Fe(dppe)中心，但 P(OMe)(3)的结合发生在 1(+)和 2(+)的相邻铁中心。中性化合物 3 通过相应阳离子的恒电位还原获得，而 2 通过 3 与 CO 的反应定量生成。通过 DFT 检查了 3 向 2 的 CO 依赖性转化以及 2(+)↔3(+)的相互转化。
