Synthesis and studies on reactivities of tetrahydrofurfurylcyclopentadienyl lanthanide chlorides Cp(s)LnCl(2)center dot 2THF (Ln = Dy, Ho, Gd) and Cp(2)(s)LnCl center dot(Ln = Sm, Dy). The crystal structures of (Cp2SmCl)-Sm-s and (Cp2Sm)-Sm-s center

摘要

Reactions of lanthanide trichloride with two or one equivalent of tetrahydrofurfurylcyclopentadienyl (Cp-s) sodium salt in THF afford bis(tetrahydrofurfurylcyclopentadienyl)lanthanide chloride complexes Cp(2)(5)LnCl [Ln = Sm (1), Dy (2)] and mono(tetrahydrofurfurylcyclopentadienyl)lanthanide dichloride complexes Cp(s)LnCl(2).2THF [Ln = Dy (3), Ho (4), Gd (9)], respectively. Treatment of 1 with one equivalent of NaPzMe(2) (PzMe(2) = 3,5-dimethylpyrazolate) forms Cp(2)(5)SmPzMe(2) (6). Complex 3 reacts with one equivalent of CpNa to yield the mixed-ring complex [(CpCpDyCl)-Cp-s](2) (7). Complexes 1-7 have been characterized by elemental analyses, infrared and mass spectroscopies. The X-ray structural analyses show that 1 and 6 are unsolvated monomers. In complex 1, the Sm atom is surrounded by two Cp-s rings, one chlorine atom and two oxygen atoms of the side-chain to form a distorted trigonal bipyramid. The coordination number of central metal is nine. In complex 6, the Sm atom is coordinated by two Cp-s rings, two nitrogen atoms of 3,5-dimethylpyrazolate, and two oxygen atoms of the side-chain with a distorted tetragonal bipyramid geometry. The coordination number of the Sm atom is ten. The investigation result shows that the strong intramolecular chelating coordination and the high steric crowding result in the lower activity of 6 toward methyl methacrylate polymerization. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 31]