Europium bis(dimethylsilyl)amides including mixed-valent Eu3[N(SiHMe2)2]6[µ-N(SiHMe2)2]2.

ABSTRACT

Trivalent Eu[N(SiHMe2)2]3(THF)2 can easily be synthesized by applying a routine salt metathesis protocol (EuCl3(THF)2 and 3 equiv. of Li[N(SiHMe2)2] in n-hexane) which crystallizes isotypically to its analogues of the rare-earth metal series (space group P21/c). Transsilylamination of Eu[N(SiMe3)2]2(THF)2 with a slight excess of HN(SiHMe2)2 in n-hexane-THF yields the divalent trinuclear compound Eu{[µ-N(SiHMe2)2]2Eu[N(SiHMe2)2](THF)}2, the solid-state structure of which differs significantly from the samarium and ytterbium analogues by showing three unique molecules in the asymmetric unit of which one is related to the two others by an inversion. Using crude Eu[N(SiMe3)2]3 in transsilylamination reactions with HN(SiHMe2)2 in n-hexane afforded n-hexane-insoluble trivalent ate complexes {MEu[N(SiHMe2)2]4}n (M = Na, K) depending on the synthesis conditions of Eu[N(SiMe3)2]3. Performing the transsilylamination of Eu[N(SiMe3)2]3 with a large excess of HN(SiHMe2)2 at elevated temperatures gave reproducibly the donor-free, mixed-valent, trinuclear compound Eu(II){[µ-N(SiHMe2)2]Eu(III)[N(SiHMe2)2]3}2 in good yield.