Structural studies of mono(pentamethylcyclopentadienyl)lanthanide complexes

Abstract

The mono(pentamethylcyclopentadienyl) lanthanide complexes [(C5Me5)Yb(μ-I)(μ-η 5 : η 5-C5Me5)Yb(C5Me5)]n (1), {[(C5Me5)Sm]3(μ-Cl)4(μ 3-Cl)(μ 3-OH)(THF)}2 (2), {[(C5Me5)Sm]2 (μ-OH)(μ-Cl)4(μ 3-Cl)Mg(THF)2}2 (3), [(C5Me5)2Sm](μ-Cl)6(μ 3-Cl)2(μ 4-Cl)[(C5Me5)Sm]4 (4), {[(C5Me5)Nd]3(μ 3-Cl)4(μ 4-Cl)2(μ 3-O2CPh)2K2(η 6-C7H8)}2 (5), [(C5Me5)Nd(C8H8)]2(μ-dioxane) (6), [(C5Me5)Yb(MeOtBu)]2(μ-η 8 : η 8-C8H8) (7), [(C5Me5)Dy(μ-I)2]3 (8), and [(C5Me5) Tm(MeCN)6]I2 (9), have been identified by X-ray crystallography. 1 is unusual in that it has a μ-η 5 : η 5-C5Me5 ring that generates a local bent metallocene environment around ytterbium. Complexes 2–5 demonstrate the versatility of bridging chlorides in generating a variety of structures for mono(pentamethylcyclopentadienyl) lanthanide halides. Complex 6 shows how dioxane can generate a crystallographically-analyzable complex by bridging two mixed-ligand metallocene units that do not readily crystallize with THF. The structure of 7 shows how methyl tert-butyl ether (MTBE) ligates a lanthanide. Complex 8 is a trimeric cyclopentadienyl lanthanide halide unusual in that it has six bridging halides that roughly define a trigonal prism. Complex 9 constitutes an organometallic example of a lanthanide in which acetonitrile completely displaces iodide counterions.