金属离子与卟啉的嵌入反应动力学研究——Ⅱ.汞(Ⅱ)催化锰(Ⅱ)嵌入四溴化四(N-乙酸甲酯基-3-吡啶基)卟啉的反应

Studies on Kinetics of Incorporation of Metal Ion into Porphyrin Ⅱ. Reaction of Mn(Ⅱ) with Tetrakis (N-carbomethoxymethyl-3-pyridyl) porphyrin

本文报道了在硝酸汞催化下Mn(Ⅱ)与四溴化四(N-乙酸甲酯基-3-吡啶基)卟啉在硼砂缓冲溶液中的反应动力学和机理。实验表明,Hg(Ⅱ)催化Mn(Ⅱ)对该类卟啉的嵌入反应是通过“坐式(SAT)”中间配合物(Hg-SAP)而完成的;在讨论催化剂浓度、溶液的pH值对反应影响的基础上,得到了表观速率常数表达式κ_(obs)=[Hg^(2+)][Mn^(2+)]/(κ_o[H^+]+k[Mn^(2+)]),其中κ_o=26.20mol·dm^(-3)·s,κ=2.59×10^(-5)mol·dm^(-3)·s,提出了该反应的机理和模式,进而论证了卟啉环的变形是金属离子通过“SAT”中间化合物嵌入卟啉反应的必要条件。

The reaction of Mn(Ⅱ) with tetrakis (N-carbomethoxymethyl-3-pyridyl) porphyrin bromide catalyzed by Hg(NO_3)_2, were studied in borax buffer.The results showed that reaction of the incorporation of Mn(Ⅱ) into the porphyrin is carried out by means of sitting atop intermediate compound (Hg-SAP).The effecf of concentration of catalyst and metal ion,pH of solution were discussed.The observed rate constant of the reaction were obtained k_(obs)=[Hg^(2+)] [Mn^(2+)] / (k_o[H^+]+k[Mn^(2+)] ), where k_o=26.20mol·dm^(-3)·s. k=2.59×10^(-5)mol·dm^(-3)·s.The mechanism of the reaction were proposed.The deformation of the ring of porphyrins is the general condition in the reaction of metal incorporation into porphyrin.