Schiff碱双核配合物的磁性及催化性能的研究

Magnetic and Catalytic Properties of New Schiff Base Dinuclear Complexes

近20多年来,用金属卟啉及Schiff碱配合物模拟细胞色素P-450单金属单加氧酶的研究工作有许多报道[1].存在于生命体中的甲烷单加氧酶是一种双金属单加氧酶.它既能催化分子氧氧化甲烷为甲醇,又能催化分子氧氧化其他一些烷烃为伯醇、仲醇及环氧化烯烃等[2].而它的结构及催化作用机制目前还不十分清楚.为了模拟甲烷单加氧酶的催化作用。

This paper reports the catalytic properties of 'porphyrin-like' Schiff base mononuclear complexes MH2L {M=Mn(II), Fe(III)Cl, Cr(III)Cl, Cu(II), Co(II), Ni(II), Zn(II); L=bis[N, N'-ethylene-2, 2'-(phenylmethylene)bis(3,4-dimethylpyrrole-5-aldimino)]} and dinuclear complexes MnML [M=Mn(II), Fe(III)Cl, Cr(III)Cl, Cu(III), Co(II), Ni(II), Zn(II)] for cyelohexane monooxygenation with PhIO and magnetic properties of the dinuclear complexes. The magnetic investigations (4 similar to 300 K) of the dinuclear complexes revealed that their antiferromagnetic spin exchange with J ranged from -10.49 to -0.482 cm(-1) except MnZnL and antiferromagnetle spin exchange decreased in the following order: Mn-II-Cu-II > Mn-II-Ni-II > Mn-II-Mn-II > Mn-II-Fe-III > Mn-II- Co-III > Mn-II-Cr-III. The results of catalyzed oxidation of cyclohexane indicated that the catalytic property of the dinuclear complex was better than that of the corresponding mononuclear complex. It was found that there was the synergism decreased in the order: Mn-Fe > Mn-Cr > Mn-Cu > Mn-Mn > Mn-Co > Mn-Ni > Mn-Zn. It seems that this synergism increases with the increase of the number of unpaired d electrons and the magnetic exchange between the two metals in these dinuclear complexes.