Tris-pyrazolylborate complexes of redox inactive lanthanides – the structures of [(Tp Me2) 2NdX] (X=Cl, NPh 2, dpm, H 2BEt 2)

Abstract

A range of complexes of Ce and Nd have been prepared to compare the chemistry of the non-reducible [(Tp Me2) 2LnX] (Ln=Ce, Nd) with that reported previously for the redox-active samarium ion. The chloride [(Tp Me2) 2NdCl] is a useful starting material for the preparation of the seven coordinate [Nd(Tp Me2) 2OAr] (Ar=C 6H 4-4-X; X=H, Bu t , Br, Ph, OMe, F, Me) and [Nd(Tp Me2) 2NPh 2]. Crystal structures of [Nd(Tp Me2) 2Cl] and [Nd(Tp Me2) 2NPh 2] are isostructural with those of the analogous samarium species. The eight coordinate species [Nd(Tp Me2) 2(β-dike)] (β-dike=(RCO) 2CH, R=Me, Ph; Bu t ) and their cerium analogues (R=Ph, Bu t ) have also been prepared. The complexes are fluxional, the extent of this behaviour depending on the steric bulk of the substituents. The structure of [Nd(Tp Me2) 2(Bu t CO) 2CH] has been determined. Finally, in efforts to prepare a neodymium hydride, the unexpected borohydride [Nd(Tp Me2) 2(H 2BEt 2)] has been isolated serendipitously and structurally characterized.