二茂基环己氧基稀土化合物的合成、分子结构和催化活性

通过Cp_3Ln(Ln=Sm, Yb)和环己醇在THF溶剂中按1：1摩匀比反应，合成了标题 化合物[Cp_2LnOC_6H_(11)]_2(Ln=Sm, Yb)。化合物经元素分析、红外光谱分析表 征。镱配合物经X单晶衍射分析。它是一个以氧原子为桥的二聚体，环己烷基呈椅 式构型，O－C（环己烷基）键处于平伏e键位置。在上述基础上，尝试了它对己内 酯的催化聚合反应，发现标题化合物对己内酯聚合具有一定的催化活性。进一步合 成了[Cp_2YbOC_6H_(11)]与己内酯的1：4预聚反应产物，发现预聚物催化己内酯聚 合活性比标题化合物大大增强，从而说明催化聚合过程中引发反应速率慢是影响标 题化合物表观催化活性的重要因素。

Synthesis and Molecular Structure of Bis(cyclopentadienyl) Cyclohexyloxy Lanthanide Compounds and Their Catalytic Activity

Reaction of CpjLn (Ln = Sm, Yb) with cyclohexanol in a 1:1 molar ratio afforded the title compounds [ CpjLnOC^Hn (Ln = Sm, Yb). They were characterized by elemental analysis and infrared spectrum. The ytterbium complex was analyzed by X-ray crystallography. It is a dimer with two oxygen atoms bridging two ytterbium atoms. The cyclohexyl group displays chair-shape configuration and the 0-C (cyclohexyl group) bond stretches as a level e-bond. [C^LnOCgHn (Ln = Sm, Yb) showed rather poor catalytic activity for the polymerization of e- caprolactone. The 1:4 adduct of [CpjYbOCgHn^ and e-caprolactone showed much better catalytic activity than its precursor [C^YbOCfiHn^. This demonstrates that the slow reaction rate of initiation is an important factor to affect the apparent catalytic activity of [Cr^YbOCgHnla for the polymerization of e-caprolactone.