Kinetics and mechanisms of ligand-substitution reactions at tetrahedral bis(diimine)copper(I) complexes in acetone and methanol
Kinetics and mechanisms of ligand-substitution reactions at tetrahedral bis(diimine)copper(I) complexes in acetone and methanol
复制标题
丙酮和甲醇中四面体双(二亚胺)铜(I)配合物的配体取代反应的动力学和机制
DOI：
10.1021/ic00028a012
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发表时间：
1992
影响因子：
4.6
通讯作者：
G. Geier
中科院分区：
文献类型：
--
作者：
U. Frei;G. Geier
用紫外-可见光谱法测定了在丙酮和甲醇溶液中Cu（biq）2+与2，9-二甲基菲咯啉（dmp）逐步取代联喹啉（biq）的反应平衡常数。用停流法研究了在这两种溶剂中混合配体络合的动力学。Cu（biq）（dmp）+的形成遵循两条平行的途径：通过外层相遇络合物的直接反应和通过中间体的溶剂辅助途径，其中一个biq配体完全解离。出乎意料的是，在这两种溶剂中的速率行为是完全不同的。在丙酮中，直接反应的总速率常数kn= Kxkh为1.8 × 101 23 M-1 s-1，其中k = 2.9 × ID 2 s-1。溶剂辅助的途径是次要的。在甲醇k中，2为7 M '1 s' 1，k = 1.1 s '1。直接途径和溶剂途径的速率相似。ktin丙酮的配体依赖性（dmp，phen）表明缔合活化模式是优选的。
The equilibrium constants for the stepwise substitution of biquinolyl (biq) by 2, 9-dimethylphenanthroline (dmp) in Cu (biq) 2+ were determined in acetone and methanol solutions by UV-visible spectroscopy. The kinetics of the mixed-ligand complexformation in these two solvents were studied by means of the stopped-flow method. Theformation of Cu (biq)(dmp)+ follows two parallel pathways: a direct reaction via an outer-sphere encounter complex and a solvent-assisted path via an intermediate in which one biq ligand is fully dissociated. Unexpectedly, the rate behavior is quite different in these two solvents. In acetone the overall rate constant for the direct reaction, kn= Kxkh is 1.8 X 101 23 M" 1 s'1 with k¡= 2.9 X ID2 s'1. The solvent-assisted pathway is of minor importance. In methanol k, 2 is 7 M'1 s'1 and k¡= 1.1 s'1. The rates for the direct pathway and the solvent pathway are similar. The ligand dependence (dmp, phen) of ktin acetone shows that an associative activation mode is preferred.