Synthesis of New Silicon‐linked Lanthanocene Complexes and Their High Catalytic Activity for Methyl Methacrylate Polymerization with Nanometric Sodium Hydride as Co‐catalyst

Abstract

The synthesis and characterization of four new silicon-linked lanthanocene complexes with pendant phenyl groups on cyclopentadiene were reported. Based on the data of elemental analyses, MS and IR, the complexes were presumed to be unsolvated and dimeric complexes [Me 2 Si(C 5 H 3 CMe 2 C 6 H 5 ) 2 LnCl] 2 [Ln＝Er (1), Gd (2), Sm (3), Dy (4)]. In conjunction with AlEt 3 or sodium hydride as the co-catalyst, these complexes could efficiently catalyze the polymerization of methyl methacrylate (MMA). When the nanometric sodium hydride was used as a co-catalyst, the complexes were highly effective for the polymerization of MMA. At low temperature and in short time, in [Me 2 Si(C 5 H 3 CMe 2 C 6 H 5 ) 2 LnCl] 2 /NaH (nanometric) system, the polymer was obtained in more than 80% yield and the molecular weight was greater than 10 5 . The activity reached that of organolanthanide hydride as a single-component catalyst. In [Me 2 Si(C 5 H 3 CMe 2 C 6 H 5 ) 2 ErCl] 2 /NaH (nanometric) system, the effects of the molar ratio of MMA/catalyst and catalyst/co-catalyst, and the temperature on polymerization were studied.

Synthesis, structure characterization and catalytic activity of lanthanide complexes containing an ansa carbonous‐bridged cyclopentadienyl—thienyl ligand

“…NaH (or nanometric NaH) was a good co-catalyst for the polymerization of MMA catalyzed by the lanthanocene complexes in our recent report. [14,15] The results were summarized in Table 1. The results indicated that the lanthanocene complexes 1-4 show catalytic behavior differently with the different co-catalysts.…”