Unusual thermodynamic behaviour on complexation of cobalt(II) with chloride, bromide and iodide ions in hexamethylphosphoric triamide
作者:Yuriko Abe、Kazuhiko Ozutsumi、Shin-Ichi Ishiguro
DOI:10.1039/f19898503747
日期:——
The complexation of cobalt(II) with chloride, bromide and iodide ions has been studied by spectrophotometry and calorimetry in hexamethyl-phosphoric triamide (HMPA) containing 0.1 mol dm–3(n-C4H9)4NCIO4 as a constant ionic medium at 25 °C. The formation of [CoXn](2–n)(n= 1–4 with X as CI, n= 1–3 with X as Br and n= 1 and 2 with X as I) is proposed, and their formation constants, enthalpies and entropies
在分光光度法和量热法中,采用分光光度法和量热法研究了钴(II)与氯离子,溴离子和碘离子的络合,其中六甲基磷酸三酰胺(HMPA)含有0.1 mol dm –3(nC 4 H 9)4 NCIO 4作为恒定离子介质,在25℃。提出了[CoX n ] (2- n)的形成(n = 1-4,X为CI,n = 1-3,X为Br,n = 1和2,X为I),其形成常数,确定焓和熵。单个钴的电子光谱(Ⅱ))还提取了卤代配合物,表明钴(II)离子在HMPA中是四配位的(不同于显示六配位的其他氧供体溶剂)和四配位的四面体[CoX n(HMPA)4– n ]。(2 – n)+(n = 1–4)逐步形成。尽管与其他非质子供体溶剂相比,HMPA具有显着强的供体性,但与N,N中的吸热性相比,在HMPA中观察到的[CoX] +形成的ΔH ° 1值甚至更小或更负。-二甲基甲酰胺或二甲基亚砜。这表明,尽管在空间上允许[co(HMPA)4