known to be high spin and labile. The kinetically determined stepwise formation constants in dmf confirm this conclusion; values vary in the order 10–3K1/dm3 mol–1 = 9.6 ± 0.7 < 10–5K2/dm3 mol–1 = 1.3 ± 0.7 > 10–3K3/dm3 mol–1 = 3.5 ± 0.2 (in water K1 > K2 K3). Overall formation constants for [Fe(bipy)3]2+ in dmf (log10 β3 = 12.6) and in dimethyl sulfoxide (log10 β3 = 10.7) are significantly smaller than
多波长停流分光光度法已用于比较[Fe(bipy)3 ] 2+(bipy =
2,2'-bipyridine)和[FeL] 2+ [L = 1,4,7 -tris(
2,2'-联吡啶基-5-基
甲基)-
1,4,7-三氮杂环壬烷,含有三个配位双联基]在二
甲基甲
酰胺(dmf )溶液中。L的分子模型及其与[Fe(dmf )6 ] 2+的反应动力学研究与两个N-构型异构体(RRR和RRS)的存在是一致的。在25°C下,RRR异构体与[Fe(dmf )6 ] 2+反应生成[FeL]2+的形成速率常数为10 –5 k f = 2.34±0.09 dm 3 mol –1 s –1, RRS异构体反应生成
中间体双(bipy)配合物,其10 –5 k f = 1.04±0.01 dm 3摩尔–1 s –1。这种双(双联)
中间体以0.71±0.02 s –1的一级速率常数重排为三联(双联)螯合物,但也参与了少量[Fe