Synthesis, characterization, and catalytic activity of divalent organolanthanide complexes with new tetrahydro-2 H-pyranyl-functionlized indenyl ligands

Abstract

Two series of new divalent organolanthanide complexes with the general formula [η 5:η 1-{1-R-3-(C 5H 9OCH 2)C 9H 5}] 2Ln II (R = H, Ln = Yb ( 3); R = Me 3Si, Ln = Yb ( 4); R = H, Ln = Eu ( 5); R = Me 3Si, Ln = Eu ( 6)) were prepared by reactions of 2 equiv. of 1-R-3-(C 5H 9OCH 2)C 9H 6 (R = H ( 1), R = Me 3Si ( 2)) with the lanthanide(III) amides [(Me 3Si) 2N] 3Ln(μ-Cl)Li(THF) 3 (Ln = Yb, Eu) via a one-electron reductive elimination process. Recrystallization of 6 from n-hexane afforded [η 5:η 1-(C 5H 9OCH 2C 9H 5SiMe 3)] 2Eu II · (C 6H 14) 0.5 ( 7). All compounds were fully characterized by elemental analyses, and spectroscopic methods. The structures of complexes 4 and 7 were additionally determined by single-crystal X-ray analyses. The catalytic activity of the complexes on methyl methacrylate and ε-caprolactone polymerization was studied, and the temperatures, substituents on the indenyl ring, and solvents effects on the catalytic activity of the complexes were examined.