STUDIES ON THE STRUCTURE AND CATALYSIS OF NONHEMEIRON COMPLEXES WHICH FUNCTION ENZYME-LIKE CATALYTIC ACTIVITY

通过有机产物的产物分析和溶液中铁络合物的光谱分析，研究了非血红素铁双加氧酶和单加氧酶模型络合物的结构和功能。以邻苯二酚铁为单加氧酶模型反应，关联了邻苯二酚双加氧酶模型反应。1.邻苯二酚双加氧酶模型体系基于邻苯二酚的催化活性，我们提出邻苯二酚形成邻苯二酚铁（III）配合物，该配合物可能与半醌铁（II）配合物处于平衡状态，作为与氧反应的直接中间体。光谱表明形成的儿茶酚铁（III），但没有直接证据的semiquinonatoiron（II）已获得。在这项研究中，我们已经分离出儿茶酚铁（III）配合物。通过ESR、Mossbauer、EXAFS等光谱技术，特别是^1H和^2H NMR，研究了配合物在溶液中的结构，明确了邻苯二酚配体的强自由基特征，支持半醌铁物种作为直接活性物种.单加氧酶模型体系我们开发了邻苯二酚铁（III）配合物/对苯二酚/O2催化剂，用于在非水有机溶剂如乙腈中催化芳烃、环状和无环饱和烃的单加氧反应。其中一个重要而有趣的结果是选择性对吡啶浓度有很大的依赖性。在低吡啶浓度下，羟基化反应为主，而在吡啶浓度下，羰基化反应为主。反应性还取决于对苯二酚上的取代基。活性物种被发现是铁氧物种，而不是羟基自由基。

Structure and function of the model complex of nonheme iron dioxygenases and mono-oxygenases were studied on the bases of product analysis of organic products and spectroscopy of the intermediate iron complexes in the solution. Catecholdioxygenase model reaction was correlated by using catecholatoiron for monooxygenase model reaction.1.Catecholdioxygenase Model SystemOn the basis of the catalytic reactivity, we have proposed that the catechol forms catechotoiron(III) complexes which may be in equilibrium with semiquinonatoiron(II) complexes as direct intermediates for the reaction with oxygen. Spectroscopy has indicated the formation of the catecholatoiron(III), but no direct evidence for the semiquinonatoiron(II) has been obtained. In this study we have isolated catecholatoiron(III) complexes. Structure of the complexes in solution was studied spectroscopically, e.g. ESR, Mossbauer, EXAFS, specially by ^1H and ^2H NMR, and the strong radical character of the catecholate ligand , supporting the semiquinonateiron species as an direct active species, has been clearly shown.2. Monooxygenase Model SystemWe have developed the catecholoteiron(III) complex/hydroquinones/O2 for the catalytic monooxygenation of aromatics, cyclic and acyclic saturated hydrocarbons in nonaqueous organic solvent such as acetonitile. One of the important and interesting results is the great dependence of selectivity on the pyridine concentration. In the low pyridine concentration, hydroxylation is the main reaction, but in pyridine carbonylation is the main reaction. The reactivity also depends on the substituents on the hydroquinones. Active species was found to be iron-oxygen species rather than the hydroxyl radical.