摘要
以2-(4,5-二甲基-2-噻唑偶氮)-5-二甲氨基苯胺为代表,应用分光光度法研究了噻唑偶氮间苯二胺类试剂与钴配合物的溶液平衡.结果表明,该配合物在溶液中存在着四种质子化型体CoR2H3+3,CoR2H2+2,CoR2H+和CoR2,它们之间存在着三级离解平衡,测定其离解常数分别为pKa1=-4.64,pKa2=0.68,pKa3=4.62.其中CoR2H2+2具有较高的摩尔吸光系数,且能在较宽的酸度范围内存在。
dimethyl 2 thiazolylazo) 5 dimethylaminoaniline chosen as example, the solution equilibrium of complex of cobalt(Ⅱ) an o aimino thiazolylazo dyes has been studied by spectrophotometric method. The results showed that the complex involves four species CoR 2H 3+ 3,CoR 2H 2+ 2,CoR 2H + and CoR 2, wihch establish three step dissociation equilibria in solution. The acidic dissociation constants for each species have been determined spectrophotometrically, pK a1 =-4.64,pK a2 =0.68,pK a3 =4.62. Among these four species, CoR 2H 2+ 2 has greatest molar absorptivity which is constantin a wide acidity range,and is suitable for analysis.
出处
《宁夏大学学报(自然科学版)》
CAS
1998年第3期255-257,共3页
Journal of Ningxia University(Natural Science Edition)