茂基烷氧基稀土化合物[(MeC_5H_4)_2Ln(μ-OCH_2CH_2NMe_2)]_2的合成、晶体结构及催化ε-己内酯开环聚合

Synthesis, Crystal Structure of [(MeC_5H_4)_2Ln(μ-OCH_2CH_2NMe_2)]_2 and Their Catalytic Activity for Ring-opening Polymerization of ε-Caprolactone

将N,N 二甲基乙醇胺按1∶1的摩尔比与三(甲基环戊二烯)稀土化合物在四氢呋喃(THF)中反应,合成了含N官能基的茂基烷氧基稀土化合物[(MeC5H4)2Ln(μ OCH2CH2NMe2)]2(Ln=Sm,Y,Nd)。产物经元素分析和红外表征,并测定了钐化合物的晶体结构。结果表明,该化合物具有二个不对称氧桥的双分子结构并存在着由氮原子向中心金属钐经分子内配位而形成的三环骨架,中心金属钐的配位数是九,整个分子呈中心对称。这类配合物对ε 己内酯开环聚合显示良好的催化活性。

Reaction of (MeC_5H_4)_3Ln with HOCH_2CH_2NMe_2 in tetrahydrofuran(THF) gave the new complexes [(MeC_5H_4)_2Ln(μ-OCH_2CH_2NMe_2)]_2 (Ln = Sm, Y, Nd) with nitrogen functionalized μ-alkoxide ligand. The complexes were characterized by elemental analysis and IR, and structure of [(MeC_5H_4)_2Sm(μ-OCH_2CH_2NMe_2)]_2 was determined by the X-ray diffraction to be a dimer formed by two unsymmetric oxygen bridges. The complex has a tricyclic skeleton with the additional two Sm-N bonds via intramolecular coordination of OCH_2CH_2NMe_2. The coordination number of the central metal Sm is nine. The title complexes show good catalytic activity for ring-opening polymerization of ε-caprolactone.