固相配位化学反应研究——ⅩⅩⅩⅩⅠ.[Co(NH_3)_5(H_2O)]Br_3,[Cr(NH_3)_5(H_2O)](NO_3)_3与无机盐KY(Y=Cl,Br,Ⅰ)的固相反应动力学研究

STUDIES ON THE SOLID STATE REACTIONS OF COORDINATION COMPOUNDS XXXXI. KINETIC STUDIES OF REACTIONS BETWEEN [Co(NH_3)5(H_2O)]Br_3, [Cr(NH_3)_5(H_2O)](NO_3)_3 AND KY(Y = Cl,Br,I) IN THE SOLID STATE

本文主要用气相色谱逸出气体分析方法,借助于红外、紫外可见漫反射谱等手段研究了[Co(NH_3)_5(H_2O)]Br_3、[Cr(NH_3)_5(H_2O)](NO_3)_3与无机盐KY(Y=Cl,Br,Ⅰ)的固相反应,计算了失水与失氨的动力学参数,发现第一步反应失水生成一取代中间产物,其活化能与外加阴离子无关,为S_N1过程。第二步失氨反应活化能与中心离子M以及取代基Y有关,当M=Co(Ⅲ)时,反应体系的失氨活化能大小有下列顺序:Cl>Br>Ⅰ(E值分别为187、155、98kJ·mol^(-1)),M=Cr(Ⅲ)时则正好相反:Ⅰ>Br>Cl(E值分别为213、146、79 kJ·mol^(-1))。

The solid state reactions between [Co(NH3)5(H2O)]Br3, [Cr(NH3)5(H2O)](NO3)3 and KY(Y = C1, Br, I) have been studied mainly by evolved gaseous analysis method. Kinetic parameters are calculated. The activation energies of deaquation-anation reactions(step 1) arc independent of the added anions, which could be interpreted by SN1 dissociative mechanism. While the activation energies of deammine reactions(step 2) are concerned with the metal ion(M) and the substituted group (Y), which decreases in the order Cl>Br>I(187, 155, 98kJ ?mol-1) for Co(III) complexes and I > Br> Cl(213,146,79kJ ?mol-1), for Cr(III) complexes.