超临界二氧化碳中卟啉与钴(II)、镍(II)、锌(II)配合物反应动力学

用紫外-可见光谱研究了钴(II)、镍(II)、锌(II)的1, 1, 1, 5, 5, 5-六氟-2, 4-戊二酮-二水配合物M(hfac)2(H₂O)₂, M=Co、Ni、Zn]与5, 10, 15, 20-四(五氟苯基)卟啉H2tpfpp]在超临界二氧化碳中反应生成金属卟啉M(tpfpp)]的反应动力学. 在金属配合物大大过量时, 反应对卟啉为一级. 其表观一级速率常数随钴(II)、镍(II)配合物的浓度增加先增加、而后趋于稳定, 而表观一级速率常数随锌(II)配合物的浓度增加线形增加. 根据实验事实, 讨论了反应的机理, 得到了相应的热力学和动力学参数.

Kinetic Study of the Reactions of Porphyrin with Co(Ⅱ), Ni(Ⅱ) and Zn(Ⅱ) Compounds in Supercritical Carbon Dioxide

The transition metal ions incorporation reactions into 5, 10, 15, 20-tetrakis (pentafluorophenyl)porphyrin(H2tpfpp) to form the metal porphyrin complexes M(tpfpp) (M= Co, Ni, Zn) have been kinetically investigated using diaquabis(1, 1, 1, 5, 5, 5-hexafluoropentane-2, 4-dionato) metal compounds M(hfac)2(H2O)2] in supercritical carbon dioxide (scCO2) medium in a spectrophotometric cell. The reactions are first order with respect to H2tpfpp under the conditions where M(hfac)2(H₂O)₂] is in large excess relative to H2tpfpp. The saturation dependence of the conditional first-order rate constants as a function of the mole fraction of the excess metal compounds M(hfac)2(H2O)2] is observed for the reaction systems Co(hfac)2(H2O)2+H2tpfpp] and Ni(hfac)2(H2O)2+H2tpfpp], and the linear dependence is observed for the reaction system Zn(hfac)2(H2O)2+H2tpfpp]. The mechanisms are discussed and the thermodynamic and kinetic parameters for the reactions are obtained.