光照条件下酚类与卟啉钴配位作用的研究  

COORDINATION BETWEEN TPP-Co AND PHENOLS UNDER PHOTO RADIATION

作　　者：李建军[1] 杜文[1] 奚祖威[1] 

机构地区：[1]中国科学院大连化学物理研究所,大连116012

出　　处：《分子催化》1991年第1期94-98,共5页Journal of Molecular Catalysis(China)

基　　金：国家自然科学基金

摘　　要：卟啉钴是一种模拟金属蛋白络合物,近年来很多人利用其模拟酶进行温和条件下的催化氧化。氧化过程中首先涉及到超氧络合物的生成。据认为轴向碱与卟啉钴发生配位作用所生成的五配位络合物是生成超氧络合物的前提,有关这方面的研究报道很多,但这些轴向碱大多是含氮有机物。在奚祖威等人研究的体系中,虽无轴向碱的存在,但TPP-Co却能将许多酚氧化。他们还研究了α-萘酚与TPP-Co的配位问题,认为α-萘酚的氧化是在卟啉配位区内进行的。我们在此基础上利用原位紫外光谱比较细致地考察了不同酚与TPP-Co的配位作用。Coordination between TPP-Co and some phenols under photo radiation was studied by in situ UV spect roscopy. Experiments were carried out in an in situ UV reactor at 20 ℃ with CHC13 as solvent .Photo radiation is important for these reactions, in dark there is no coordination reaction between TPP and the most active α-naphthol. Under photo radiation, TPP-Co itself has a red-shift in its UV spectrum ( Fig. 3 ), which could be illustrated by the Co valence electron energy level diagram ( Fig. 4 ). When phenols were added to the reaction system, the UV spectra undergo more rapid change, which has different rates for different phenols: α-naphthol the fast, phenol the slowest ( Fig. 5 ) . Pyridine can coordinate with TPP-Co even without radiation, but photo radiation can accelerate this reaction remarkably ( Fig. 6 ). The substitutes on aromatic ring have some influence on the coordination reactions. The rates of spectra change are decreased according to the following order: α-naphthol>2,4,6-trimethylphenol >o-methylphenol>phenol, which is in agreement with the oxidation sequence of phenols. If the radiation is stopped after the maximum change of spectrum is reached ( using α-naphthol as substrate), the spectrum returns gradually to its original state, which revealed that the reaction is reversible. If the photo radiation is prolonged for a long time after the maximum, TPP system could be destroyed. But both phenomena do not happen when pyridine is taken as substrate. Mechanism of these reactions are discussed.

关 键 词：卟啉钴 酚 钴 配位 光照 

分 类 号：O614.812[理学—无机化学]