Synthesis, solid state structure, and solution behaviour of the lighter lanthanide bis(trimethylsilyl)amido chlorides, [Ln{N(SiMe3)2}2(THF)(µ-Cl)]2 (Ln = Ce, Nd)

Abstract

The synthesis of [Ln{N(SiMe3)2}2(THF)(µ-Cl)]2 (Ln = Ce, 1; Nd, 2) by reaction of sodium bis(trimethylsilyl)amide (2 equiv.) with LnCl3 is reported. The same complexes were also isolated from the ligand redistribution reactions of Ln[N(SiMe3)2]3 and LnCl3 (2:1 ratio) in THF at 80°C. The crystal structure of 2, determined by X-ray diffraction, revealed a centrosymmetric dimer with bridging chlorides and pentacoordinate metal centres. 1H NMR studies show that the solid state structure is not maintained in solution. NMR evidence for the presence of Ln[N(SiMe3)2]3 and two other bis(trimethylsilyl)amide containing species, presumably Ln[N(SiMe3)2]Cl2(THF)x and Ln[N(SiMe3)2]2Cl(THF)y, is presented.Key words: lanthanide, amide, neodymium, cerium, crystal structure, X-ray, nuclear magnetic resonance, redistribution.