Abstract
The reactions of anhydrous LnCl~3~ (Ln = Y, Nd, Sm, Lu) with two equiv. of sodium N,N′‐dicyclohexyl‐N′′‐bis(trimethylsilyl)guanidinate Na[(Me~3~Si)~2~NC(NCy)~2~], obtained from Na[N(SiMe~3~)~2~] and the 1,3‐dicyclohexyl‐substituted carbodiimide CyN=C=NCy in THF, yield the monochloro bis(guanidinate) tetrahydrofuranate complexes [(Me~3~Si)~2~NC(NCy)~2~]~2~LnCl(THF) [Ln = Y (1), Nd (2), Sm (3) and Lu (4)]. The analogous reactions of YCl~3~ and LuCl~3~ with the lithium guanidinate [Li(Et~2~O)][(Me~3~Si)~2~NC(NCy)~2~] afford the bis(guanidinate) “ate” complexes [(Me~3~Si)~2~NC(NCy)~2~]~2~Ln(μ‐Cl)~2~Li(THF)~2~ [Ln = Y (5) and Lu (6)]. Treatment of 5 with dimethoxyethane results in the formation of [(Me~3~Si)~2~NC(NCy)~2~]~2~Y(μ‐Cl)~2~Li(DME) (7). The carbyl complexes [(Me~3~Si)~2~NC(NCy)~2~]~2~Y‐__t__Bu] (8), [(Me~3~Si)~2~NC(NCy)~2~]~2~Y(μ‐Me)~2~Li(TMEDA) (10) and [(Me~3~Si)~2~NC(NCy)~2~]~2~YPh(THF) (13) were obtained by interaction of complex 1 with RLi (R = __t__Bu, Me or Ph). The molecular structures of 1, 6, 7, 8 and the side product [Li(TMEDA)][(Me~3~Si)~2~NC(NCy)~2~] have been determined by single‐crystal X‐ray analyses. Agostic interactions between the yttrium atom and the tert‐butyl group in complex 8 in the solid state as well as in solution have been substantiated by ^13^C NMR spectroscopy and X‐ray analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)