金属羰基化合物的结构对氧原子转移反应速率的影响

EFFECT OF STRUCTURAL FACTORS ON THE RATES OF OXYGEN ATOM TRANSFER TO METAL CARBONYLS

本文研究了氧化三甲胺Ｍｅ３ＮＯ与羰基簇合物Ｍ４（ＣＯ）１２－ｎＬｎ（Ｍ＝Ｃｏ，Ｉｒ；ｎ＝１，２；Ｌ＝磷配体）的氧转移反应动力学，讨论了反应机理．反应符合二级速率方程：ｒ＝的氧转移反应活性呈现如下顺序：中心元素不同时取代配体不同时Ｍ４取代程度不同时本文重点讨论了配合物的结构因素对氧转移反应活性的影响．

The comparative study on kinetics and mechanism was made to examine further the importance of CO bridging concept to the reactivity of metal clusters in the CO substitution by L ofM4(CO)12-nLn(M=Co, Ir; L=phosphorous ligand; n=1,2) in the presence of Me3NO. Thesecond-order rate law and kinetic behavior arc the same as that reported earlier on such reaction and hence provide a common basis for comparision. The reaction rates of Ir compoundsare greater than those of corresponding Co compounds (Co<Ir) with the phosphorous ligandsstudied in this paper. The results obtained here are different from earlier studies on theM3(CO)12 and M3(CO)11L (M =Fe, Ru, Os) where it was found that the reactivities decrease inthe order Fe> Ru > Os and this was discussed in terms of the presumed important contributionof CO bridging to the rates of associative reactions in metal carbonyl clusters. Some other effects of structural factors on rates of the oxygen atom transfer to metal carbonyls were also discussed.