Ni(I) and Ni(II) Bis(trimethylsilyl)amides Obtained in Pursuit of the Elusive Structure of Ni{N(SiMe)}.

Salt metathesis routes to five new -N(SiMe) nickel derivatives were studied to illuminate their mode of formation, structures, and spectroscopy. The reaction between NiI and K{N(SiMe)} afforded the Ni(II) and Ni(I) complexes [K][Ni{N(SiMe)}] () and [K][Ni{N(SiMe)}] (). Dissolving in tetrahydrofuran (THF) gave the Ni(II) species [K(THF)][Ni{N(SiMe)}] (). The Ni(I) salt [K(DME)][Ni{N(SiMe)}] () was obtained by using NiCl(DME) (DME = 1,2-dimethoxyethane) as the nickel source rather than NiI. The isolation of the Ni(I) complexes and highlights the tendency for K{N(SiMe)} to function as a reducing agent. Introduction of adventitious O to solutions of [K][Ni{N(SiMe)}] () gave the nickel inverse crown ether (ICE) species [K][O(Ni{N(SiMe)})] (). Complex is the first ICE complex of nickel and is one of four known ICE complexes for the 3d metals. The experimental results indicate that the reduced Ni(I) bis(trimethylsilyl)amides are relatively easily generated, whereas Ni(III) derivatives that might be expected from a disproportionation of a Ni(II) derivative are apparently not yet isolable by the above routes. Overall, the new species crystallize readily from the reaction mixtures, but under ambient conditions, they begin to decompose as solids within ca. 24 h, which hinders their characterization.