Thermodynamic and kinetic effects of 12-membered macrocycles. Polarographic studies of 1,4,7,10-tetra-azacyclododecanecopper(II)
作者:Mutsuo Kodama、Eiichi Kimura
DOI:10.1039/dt9760000116
日期:——
Thermodynamic parameters and reaction rates for complex formation between Cu2+ and 1,4,7,10-tetra-azacyclododecane (tcdd) have been determined polarographically. The stability constants (log K 24.8 at 25 °C) for the 1 : 1 complex is more than 104-fold greater than that for the corresponding open-chain tetra-amine, 3,6-diazaoctane-1,8-diamine (3,6NH-od). The enhanced stability with tcdd is entirely
Cu 2+和1,4,7,10-四氮杂环十二烷(tcdd)之间形成络合物的热力学参数和反应速率已通过极谱法确定。1:1配合物的稳定性常数(在25°C下的log K 24.8)比相应的开链四胺,3,6-二氮杂辛烷-1,8-二胺的稳定常数大10 4倍( 3,6NH-od)。tcdd增强的稳定性完全归因于更有利的熵变,这与因Hinz和Margerum产生更有利的焓变而导致的14元大环效应形成鲜明对比。速率常数为1.84×10 6和1.80×10 –1 dm 3 mol –1 s –1[Cu(O 2 CMe)] +与Htcdd +和H 2 tccd 2+的反应。双质子化物质反应迟缓表明速率确定步骤是一个关联过程,可能是在第二键形成之前质子损失。解离速率常数反映了增加的12元大环配合物的稳定性常数。