Axial ligand effect on the reaction mechanism of head-to-head pivalamidato-bridged Pt(III) binuclear complex containing an equatorial bromide ligand with acetone
Axial ligand effect on the reaction mechanism of head-to-head pivalamidato-bridged Pt(III) binuclear complex containing an equatorial bromide ligand with acetone
复制标题
轴向配体对含赤道溴化物配体的头对头新酰胺基桥联Pt(III)双核配合物与丙酮反应机理的影响
DOI：
10.1016/j.ica.2015.04.020
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发表时间：
2015
影响因子：
2.8
通讯作者：
Kazuko MATSUMOTO
中科院分区：
文献类型：
--
作者：
Masatoshi KISHI;Takaaki TERADA;Yu KURAISHI;Tomoaki SUGAYA;Satoshi IWATSUKI;Koji ISHIHARA;Kazuko MATSUMOTO
在酸性水溶液中研究了含赤道Br−配体的新戊酰胺桥联铂（III）双核配合物[（H2O）（NH3）2 Pt（μ-pivalamidato）2 Pt（Br）2（OH 2）]2+（配合物1）和[（Br）（NH3）2 Pt（μ-pivalamidato）2 Pt（Br）2（Br）]（配合物2）与丙酮的轴向配体取代反应动力学.这两种配合物与丙酮缓慢反应，丙酮基PtIII双核配合物的形成分两步进行（1和2）。在给定的[H+]下，络合物1和2的反应步骤1的准一级速率常数（kobs 1）分别与过量配体浓度（CL）呈线性和二次函数关系.两个反应中第2步的速率常数均与Cl和[H+]无关。络合物1的反应机理与HH四氨酰胺桥联双铂（III）络合物与丙酮的反应机理相似，其中一个中间体与一个π配位的丙酮分子参与反应。与此相反，一个中间体与两个π-配位丙酮分子的轴向网站上提出的反应机理为配合物2。
The axial ligand substitution reactions of head-to-head (HH) pivalamidato-bridged platinum(III) binuclear complexes containing equatorial Br−ligands, ([(H2O)(NH3)2Pt(μ-pivalamidato)2Pt(Br)2(OH2)]2+(complex1) and [(Br)(NH3)2Pt(μ-pivalamidato)2Pt(Br)2(Br)] (complex2)) with acetone were kinetically investigated in acidic aqueous solutions. Both the complexes reacted with acetone slowly and acetonyl PtIIIbinuclear complexes were formed in two steps (1 and 2). The observed pseudo first-order rate constants (kobs1) for step 1 of the reactions of complexes1and2were linearly and quadratically dependent on the excess ligand concentration (CL) at a given [H+], respectively. The rate constants for step 2 in both the reactions were independent of bothCLand [H+]. A reaction mechanism involving an intermediate with one π-coordinated acetone molecule was proposed for complex1, which is similar to those proposed previously for the reactions of HH tetraammine amidato-bridged diplatinum(III) complexes with acetone. In contrast, a reaction mechanism involving an intermediate with two π-coordinated acetone molecules on the axial sites was proposed for complex2.