Crystal structure and kinetics of the acid-catalysed decomposition of (N,N′-bis(2-pyridylmethylene)-1,3-diamino-2,2-dicarboxyethylpropane)copper(II)perchlorate
作者:Ann McConnell、Philip Lightfoot、David T Richens
DOI:10.1016/s0020-1693(01)00778-2
日期:2002.3
CuN bond cleavage. The rate constant for the H+-dependent faster stage carries a [H+]2 dependence suggesting that here protonation of both secondary NH groups occurs within the rate-determining step prior to decomposition. Assistance from the axial site is also proposed. Absorbance changes monitored as a function of [H+] for the ∼10× slower second stage suggest that it may involve intermediates resulting
摘要配合物[CuL(OH)2](ClO4)2·H2O的晶体结构。首次确定的L = N,N'-双(2-吡啶基亚甲基)-1,3-二氨基-2,2-二羧乙基丙烷显示出五角配位的铜(II)中心呈扭曲的方金字塔形几何结构,具有弱键合轴向水分子。为了评估通往假定的游离配体N,N'-双(2-吡啶基亚甲基)-1,3-二氨基丙烷-2-羧酸的可能途径,该配合物对酸和碱性水溶液的行为(稳定性)为调查。在25°C的1.0 M酸性氯化物介质中,该络合物分两个阶段缓慢分解,除了含水Cu2 +外,还生成了2-吡啶基甲基铵氯化物,甲醛和丙二酸二乙酯。初始快速阶段既具有与H +相关的路径(5.32±0.18×10-5 M-2 s-1),又具有独立的(1.59±0.10×10-5 s-1)路径,后者被认为反映了在不稳定的轴向位点上氯离子的快速平衡,然后进行了速率测定异构化反应以在轴向位点上放置一个CuNH键,从而导致CuN键断裂。H