Synthesis and crystal structures of tris(2-methoxyethylcyclopentadienyl)lanthanide complexes

Abstract

The tris(2-methoxyethylcyclopentadienyl)lanthanide complexes [Ln(C₅H₄CH₂CH₂OMe)₃](Ln = La, Pr, Nd, Gd or Y) were synthesized by the reaction of sodium 2-methoxyethylcyclopentadienide with the corresponding LnCl₃ and the products were characterized by elemental analyses, mass, IR and ¹H NMR spectroscopy. Crystal structure determinations revealed the complexes to be unsolvated monomeric metallocenes with lanthanide centres co-ordinated by three cyclopentadienyl rings and two oxygen atoms of the three 2-methoxyethyl moieties present; the third oxygen is not co-ordinated. The distances Ln–C (η⁵) and Ln–O(1)(co-ordinated oxygen) decrease as the ionic radius decreases; however, Ln–O(3)(co-ordinated oxygen) increases.