A series of cobalt porphyrins derived from hemin was prepared as cytochrome P450 models. Effects of substituents at the cobalt deuteroporphyrin-propionate side chains are investigated in oxidation of toluene with air to benzaldehyde and benzyl alcohol without the use of solvent and sacrificial co-reductant. The catalytic activity of cobalt porphyrins depends on the type of substituents. When the electron-withdrawing groups like –Cl, –Br, were introduced into the double propionate side chains, they can increase the catalyst stability and selectivity to benzaldehyde. In comparison with these electron-withdrawing groups, the electron-donor groups, such as –CH3, –S–S– and –NH2 groups, can improve their catalytic activities. Moreover, the electron-donor group containing an unpaired electron (such as –S–S–, –NH2) is benefit for improving its catalytic efficiency and promoting the electron delivery. It can be concluded that the double propionate side chains in the deuteroporphyrin complex may participate in oxidation process and effect electron transfer from the high-valent metalloporphyrin species to the substrate.

中文翻译：

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一系列钴卟啉作为细胞色素P450模型的合成及催化性能：取代基对催化活性的影响

制备了一系列源自血红素的钴卟啉作为细胞色素 P450 模型。在不使用溶剂和牺牲助还原剂的情况下，研究了在用空气将甲苯氧化成苯甲醛和苯甲醇中重卟啉丙酸钴侧链上的取代基的影响。钴卟啉的催化活性取决于取代基的类型。当-Cl、-Br等吸电子基团被引入双丙酸酯侧链时，它们可以增加催化剂的稳定性和对苯甲醛的选择性。与这些吸电子基团相比，给电子基团，如–CH3、–S–S–和–NH2基团，可以提高它们的催化活性。此外，包含未成对电子（如-S-S-、–NH2) 有利于提高其催化效率和促进电子传递。可以得出结论，氘代卟啉复合物中的双丙酸侧链可能参与氧化过程并影响电子从高价金属卟啉物种到底物的转移。