不同取代基铁咔咯配合物对苯乙烯的催化氧化

Catalytic Styrene Oxidation by Iron Corroles Bearing Different Substituents

合成了4种具有不同推-拉电子强度取代基的铁咔咯配合物,并通过紫外,核磁,质谱等手段对化合物进行了表征。考察了在乙腈溶液中,以叔丁基过氧化氢(TBHP),亚碘酰苯(Ph IO),双氧水(H2O2)为氧源时,4种不同取代基铁咔咯配合物对于苯乙烯的催化氧化效果,并考察了咪唑作为轴向配体时对反应的影响。结果表明,产物的产率与氧源,催化剂和轴向配体均有关。以TBHP为氧源时,苯甲醛为主要产物;以Ph IO作为氧源时,主要产物则为环氧苯乙烷;而当氧源为H2O2时,4种铁咔咯均不能有效地催化苯乙烯氧化。使用不同的氧源时,4种铁咔咯展现不一样的催化活性顺序,其催化过程可能涉及自由基和高价态的Fe髨-oxo咔咯。铁咔咯能与咪唑形成1∶2的配合物,在催化体系中加入咪唑后,在不同的氧源条件下,咪唑对于反应产物的分布影响不同。

Four meso-substituted iron（IV） corroles having different number of pentafluorophenylor phenyl groups were synthesized and characterized by UV-Vis, NMR and MS. The catalytic styrene oxidation by these iron corroles using ten-butyl hydroperoxide （TBHP）, iodosylbenzene （PhlO）, hydrogen peroxide（H2O2） in acetonitrile was investigated. The effect of imidazole as axial ligand on the catalytic oxidation was also examined. The results indicate that the yields of the products depend on oxidants, catalysts and axial ligand. For TBHP, benzaldehyde is the major product. Styrene epoxide is the major product when using PhIO oxidant. All iron（IV） corroles studied cannot effectively catalyze styrene oxidation by using H2O2. Four iron corroles exhibit different activity order when using different oxidants, and the catalytic process may involve free radical and Fe（V）-oxocorrole species. The axial coordination of F15C-Feby imidazole gives 1：2 complexes. Also, axial ligand imidazole has different effect on the oxidation product distribution when using different oxidants.