摘要:
Treatment of the chloride metallocene [eta(5)-1,3-(Me3C)(2)C5H3](2)ThCl2 or [eta(5)-1,2,4-(Me3C)(3)C5H2](2)ThCl2 with 2 equiv of PhCH2K in diethyl ether at room temperature gives, after recrystallization from a benzene solution, the benzyl metallocenes [eta(5)-1,3-(Me3C)(2)C5H3](2)Th(CH2Ph)(2) (1) and [eta(5)-1,2,4-(Me3C)(3)C5H2](2)Th(CH2Ph)(2) (2), respectively, in good yields. Complexes 1 and 2 have been characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction analyses. They are active catalysts for the polymerization of rac-lactide, leading to the atactic polylactides with high molecular weights and narrow molecular weight distributions. (C) 2013 Elsevier B.V. All rights reserved.