通过在3-叔丁基水杨醛C5位引入咪唑盐基,再与(1S,2S)-二苯基乙二胺缩合得到手性Salen配体,该配体与醋酸锰配位、空气氧化以及氯离子置换得到水溶性手性Salen-Mn(Ⅲ)配合物.采用傅里叶变换红外光谱、高分辩率质谱以及元素分析对其结构进行了表征.以1-苯乙醇的氧化动力学拆分为模型反应,以二氯甲烷和水混合物为溶剂,溴化钾为添加剂,并以二乙酸碘苯为氧化剂,考察了所合成的水溶性手性Salen-Mn(Ⅲ)配合物对仲醇氧化动力学拆分反应的催化性能.结果表明:咪唑盐基的引入提高了氧化反应的速率,但却大大降低了仲醇氧化动力学拆分反应的拆分性能,表明手性Salen Mn(Ⅲ)配合物结构中C5位基团的大的空间位阻有利于仲醇氧化动力学拆分.
A chiral Salen ligand was synthesized by the incorporation of an imidazolium salt moiety in the C5 position of 3-isobutyl salicylaldehyde,and then condensation with (1S,2S)-diphenylethylenediamine.The obtained ligand coordinated with manganese acetate,followed by aerobic oxidation and chlorine anion substitution to give a water soluble chiral Salen Mn(Ⅲ) complex.The structure of the complex was characterized by FT-IR,HR-MS and elemental analysis.The catalytic performance of the complex on the oxidative kinetic resolution of secondary alcohols was evaluated by using the resolution of 1-phenylethanol as model reaction together with dichloromethane water mixture as solvent,potassium bromide as additive and iodobenzene diacetate as oxidant.The results revealed that the incorporation of the imidazolium salt increased the catalytic activity of the complex,but highly deteriorated its performance on the oxidative kinetic resolution (OKR) of secondary alcohols.The results indicated that large steric hindrance of the group in the C5 position of a chiral Salen Mn(Ⅲ) complex is favor of the OKR of secondary alcohols.