非对称Schiff碱过渡金属配合物模拟酶催化烯烃环氧化(Ⅰ)

Epoxidation of Unfunctionalized Olefins Catalyzed by Unsymmetric Schiff-base-Mn(Ⅲ) Complexes

研究了温和条件下以亚碘酰苯为氧源，非对称性的和对称性的Mn（Ⅲ）Schiff碱配合物[Mn（Ⅲ）（CBP－phen－Xsal）Cl，X=H，Cl，Br，NO2，CH3，OCH3]和[Mn（Ⅲ）（CBP－R－CBP）Y，R=CH2CH2－，－CH（CH3）CH2－，－C6H4－；Y=Cl，OCH3]催化非官能性烯烃苯乙烯、环己烯和α-甲基苯乙烯的环氧化反应．结果表明，非对称配合物Mn（Ⅲ）（CBP－phen－Xsal）Cl是一个良好的催化非官能性烯烃环氧化反应的催化剂体系；中心金属离子Mn（Ⅲ）的电子结合能越小，催化环氧化效果越好；对上述3种烯烃环氧化物最好收率分别达到73％、100％和92％．

篢he selective epoxidation of unfunctionalized olefins (styrene, cyclohexene,a-methylstyrene) catalyzed by synthesized unsymmetric Schiff-base-Mn (Ⅲ) complexesMn(CBP-phen-XSal)Cl [X = H, C1, Br, NO2, CH3, OCH3] and the symmetric analogsMn(CBP-R-CBP)Y[R =CH2CH2, CH (CH3)CH2, C6H4; Y=Cl, OAc] was investigated un-der mild conditions with iodosylbenzene as the terminal oxidant. The results show that theunsymmetric complexes Mn(Ⅲ) (CBP-phen-XSal)Cl is an effective system in catalytically se-lective olefin-epoxidation; the smaller the binding energy of Mn(Ⅲ), the more effective inepoxidation; the highest epoxidation yields of the mentioned three olefins are 73%, 100%and 92% respectively.