Schiff碱配合物拟酶催化反应的取代基效应研究

Studies on the Substituent Effects of New Schiff Base Complexes on the Catalytic Monooxygenation of Cyclohexane

系统地研究了新型 Schiff碱双核配合物在拟酶催化 Ph IO单加氧化环己烷反应中的取代基效应 .结果表明 ,这些配合物的环外苯基及环上亚苯基上吸电子取代基均能提高配合物的催化活性 ,而给电子取代基作用相反 ;环上亚苯基上的取代基效应比环外苯基上的取代基效应更明显 ;催化反应表观速率常数 k与环外苯基上的取代基特性常数 σ( σm 或 σp)及环上亚苯基上的取代基特性常数 ( σm+σp)呈良好的线性关系 :lgk=0 .1 658σ-6.0 90及 lgk=0 .7394 [( σm+σp) /2 ]-6.4

This paper reports the biomimetic catalytic effect of new Schiff base complexes Mn 2L(L= bis[ N,N alkylene 2,2 (arylmethylene)bis(3, 4 dimethylpyrrole 5 aldimino)]) on the mono oxygena\|tion of cyclohexane with PhIO. The results showed that contrary to electron donating groups, electron withdrowing groups on the phenyl groups or/and the phenylene groups of the complexes could increase their catalytic activities in the biomimetic catalysis system; with respect to the catalytic monooxygenation, the substituent effects on the phenylene groups of the complexes are greater than those on the phenyl groups; there are linear relationships between the reaction kinetic constant k and the substituent constant σ : lg k = 0.165 8 σ - 6.090 for the complexes with substituents on the phenyl groups and lg k =0.739 4 [( σ m+σ p )/2]- 6.478 for the complexes with substituents on the phenylene groups.