Two-electron transfer accompanied by metal−metal bond formation. Synthesis and electrochemistry of dinuclear molybdenum and tungsten carbonyl thiolates
Two-electron transfer accompanied by metal−metal bond formation. Synthesis and electrochemistry of dinuclear molybdenum and tungsten carbonyl thiolates
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DOI：
10.1021/ic00262a036
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发表时间：
1987-07
影响因子：
4.6
通讯作者：
Doris A. Smith;B. Zhuang;W. Newton;J. W. Mcdonad;F. A. Schultz
中科院分区：
文献类型：
--
作者：
Doris A. Smith;B. Zhuang;W. Newton;J. W. Mcdonad;F. A. Schultz
[M2（CO）_8（SR）_2]~（2-）→ [M_2（CO）_8（SR）_2]~（2+）（i）在乙腈中氧化，生成单体M物种[M（CO）_5（SR）]~（4）（M= Mo，R= Ph，r-Bu），用过量CO处理，通过氧化还原，溶剂分解，和羰基化反应以及溶剂分解和羰基化反应对电极反应的影响（EqI）。M2氧化成M2二聚体伴随着单个金属-金属键的形成和M2（SR）2核内的显著重排。这些变化显然提供了驱动力，使两个电子转移发生在一个单一的步骤。与结构类似化合物的比较表明，随着M2-*· M* 2氧化，MM键长收缩约1.0 π，MSM桥角收缩约25 π。尽管这些大的位移在核坐标，电极反应i表现出能斯特双电子行为的循环伏安法在0.1 V s-1。这种动力学上容易的行为表明，在[M2（CO）8（SR）2] 2-转化为M2（CO）8（SR）2中涉及的核重排以这样的方式进行协调，使得对电子转移呈现低活化能势垒。
[M2 (CO) 8 (SR) 2] 2-^[M2 (CO) 8 (SR) 2]+ 2e"(i) oxidation in acetonitrile, andto the monomeric Mspecies,[M (CO) 5 (SR)]~(4)(for M= Mo, R= Ph, r-Bu), bytreatment with excess CO. Interconversion of 1-4 by means of redox, solvolysis, and carbonylation reactions and the influence of the solvolysis and carbonylation reactions on electrode reactions (eq i) are described. Oxidation of the M 2 to the M [2 dimers is accompanied by formation of a single metal-metal bond and significant rearrangement within the M2 (SR) 2 core. These changes apparently supply the driving force that enables two-electron transfer to occur in a single step. Comparisonswith structurally analogous compounds indicate that contractions of~ 1.0 Á in the MM bond distance and of~ 25 in the MSM bridge angle accompany M 2-*· M* 2 oxidation. Despite these large displacements innuclear coordinates, electrode reaction i exhibits Nernstian two-electron behavior by cyclic voltammetry at 0.1 V s'1. This kinetically facile behavior suggests that the nuclear rearrangement involved in conversion of [M2 (CO) 8 (SR) 2] 2~ to M2 (CO) 8 (SR) 2 is concerted in such a way that a low activation energy barrier is presented to electron transfer.