四苯基卟啉蒽醌化合物的质子化热力学  

Thermodynamics of Protonation Reaction of Porphyrinanthraquinone Compounds

作　　者：胡珍珠[1] 朱志昂[2] 陈东 

机构地区：[1]湖北师范学院化学与环境工程系,黄石435002 [2]南开大学化学系 [3]华中科技大学同济医学院

出　　处：《应用化学》2004年第8期770-774,共5页Chinese Journal of Applied Chemistry

基　　金：国家自然科学基金 ( 2 0 1710 2 4);湖北省教育厅基金 ( 2 0 0 4D0 0 5 )资助项目

摘　　要：用光度法测得 5种四苯基卟啉蒽醌化合物的表观质子化常数 ,以lnKθ对 1/T作线性回归 ,求出质子化过程的△rHθm<0及△rSθm>0。探讨了取代基的电子效应、空间效应对质子化常数的影响 ,并通过半经验量子化学计算方法PM 3计算了卟啉环中 2个氮原子 (N )的净电荷和前线轨道能量差。The overall protonation constants of five porphyrin-anthraquinone compounds were determined by spectrophotometric method. The changes of standard molar enthalpy △ rHθ m<0 and standard molar entropy △ rSθ m>in the protonation reaction were calculated from the plots of lg K θ vs 1/T. The in electron effect and steric hindrance of substituent groups on overall protonation constants were discussed .The net charge at N atom as well as the frontier orbital energy difference of porphyrin molecules were calculated by using semiempirical PM3 method. Experimental data showed that the protonation degree of porphyrins depends on the net charge at N atom as well as the frontier orbital energy difference of porphyrin and steric hindrance of substituent group.

关 键 词：卟啉蒽醌化合物 表观质子化常数 电子吸收光谱 PM3 

分 类 号：O642.5[理学—物理化学]