四（2─咪唑基）卟啉在水溶液中的性质及其在乙酸中与Co（Ⅱ）（OAc）_2的反应动力学研究

PROPERTIES OF TETRAKIS-(2-IMIDAZOYL) PORPHYRIN IN AQUEOUS SOLUTION AND STUDIES ON THE KINETICS OF REACTION WITH CO(Ⅱ)(OAc)_2

合成了水溶性四（２─咪唑基）卟啉（Ｈ２＿ＴＩｍＰ），研究了它在水溶液中的聚合性质．实验发现Ｈ２ＴＩｍＰ水溶液在ＰＨ＝０，６时遵守Ｂｅｅｒ定律，并呈单体形式存在．用光谱滴定法测定了Ｈ＿２ＴｌｍＰ加质于的平衡常数．用紫外可见分光光度计研究了在乙酸溶剂中Ｈ＿２ＴＩｍＰ与Ｃｏ（Ⅱ）（ＯＡｃ）２反应的动力学．提出与实验结果相吻合的反应机理，并求得预平衡步的Ｋ， 以及速控步的Ｋ，讨论了溶剂化对标准摩尔熵及活化熵的影响．

he water-soluble tetrakis-(2-imidazoyl)-porphy was synthesised and its polymerization propertics in aqueous solution was investigated.It was found that H2TImP obeyed Beer's law at pH = 0, 6, and remained monomerie.The equilibrium constant for the addition of the protons to the free base form of H2TImP was determined by spcctrophotomctric titration. The kinetics of the reaction of H2TImP with Co(Ⅱ)(OAc)2 in acetic acid was studied by means of Shimadzu UV-240 spectrophotomctcr.A mechanism in consistent with experimental results has been proposed. The parameters of a pre-equilibrium step and k,of a rate-determing step were evaluated. The effects of the solvation on the change of standard molar entropy and activation entropy were discussed.