Role of halide ion in the mechanism of protonolysis of the PtC bond in Pt(II) alkyl and aryl complexes
作者:G. Alibrandi、D. Minniti、R. Romeo、P. Uguagliati、L. Calligaro、U. Belluco、B. Crociani
DOI:10.1016/s0020-1693(00)88298-5
日期:1985.5
Abstract A mechanistic study is described for the electrophilic cleavage of the Pt C σ bond in complexes cis -[PtPh 2 (PEtPh 2 ) 2 ] and trans -[PtXR(PEt 3 ) 2 ] (X = Cl and Br, R = Me, Et, n-Pr, n-Bu, CH 2 Ph) by the proton in the presence of halide ions in aqueous methanol (MeOH/H 2 O, 91v/v) which yields cis -[PtClPh(PEtPh 2 ) 2 ] and trans -[PtX 2 (PEt 3 ) 2 ], respectively. The reactions are first-order
摘要描述了顺式-[PtPh 2(PEtPh 2)2]和反式-[PtXR(PEt 3)2](X = Cl and Br,R = Me ,在甲醇水溶液(MeOH / H 2 O,91v / v)中存在卤离子的情况下,通过质子对质子进行分析,得到Et,n-Pr,n-Bu,CH 2 Ph),生成顺式-[PtClPh(PEtPh 2)2]和反式-[PtX 2(PEt 3)2]。对于这两个系统,反应在底物中都是一阶的,并且服从一般的双变量率定律k obs = [H +] k H + kx K [[X-]} /(1 + K [[X-]])。拟议中的机制涉及通过卤化物与正方形平面底物的相互作用快速实现铂(II)阴离子中间体的快速平衡前形成(K),同时结合底物(k H)和中间体的缓慢平行质子化(kx),导致金属碳σ键断裂。应该将中间体视为弱缔合产物,因为所有通过紫外,可见光和31 P 1 H} NMR光