Tris-pyrazolylborate complexes of redox inactive lanthanides the structures of [(TpMe2)2NdX] (X = Cl, NPh2, dpm, H2BEt2)

A range of complexes of Cc and Nd have been prepared to compare the chemistry of the non-reducible [(Tp(Me2))(2)LnX] (Ln = Ce, Nd) with that reported previously for the redox-active samarium ion. The chloride [(Tp(Me2))(2)NdCl] is a useful starting material for the preparation of the seven coordinate [Nd(Tp(Me2))(2)OAr] (Ar=C6H4-4-X; X=H, Bu-t, Br, Ph, OMe, F, Me) and [Nd(Tp(Me2))(2)NPh2]. Crystal structures of [Nd(Tp(Me2))(2)Cl] and [Nd(Tp(Me2))(2)NPh2] are isostructural with those of the analogous samarium, species. The eight coordinate species [Nd(Tp(Me2))(2)(beta-dike)] (beta-dike=(RC=O)(2)CH, 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)((BuCO)-C-t)(2)CH] has been determined. Finally, in efforts to prepare a neodymium hydride, the unexpected borohydride [Nd(Tp(Me2))(2)(H2BEt2] has been isolated serendipitously and structurally characterized. (C) 2003 Elsevier Ltd. All rights reserved.