The Instability of Ni{N(SiMe 3 ) 2 } 2 : A Fifty Year Old Transition Metal Silylamide Mystery

The characterization of the unstable Ni II bis(silylamide) Ni{N(SiMe 3 ) 2 } 2 ( 1 ), its THF complex Ni{N(SiMe 3 ) 2 } 2 (THF) ( 2 ), and the stable bis(pyridine) derivative trans‐Ni{N(SiMe 3 ) 2 } 2 (py) 2 ( 3 ), is described. Both 1 and 2 decompose at ca. 25 °C to a tetrameric Ni I species, [Ni{N(SiMe 3 ) 2 }] 4 ( 4 ), also obtainable from LiN(SiMe 3 ) 2 and NiCl 2 (DME). Experimental and computational data indicate that the instability of 1 is likely due to ease of reduction of Ni II to Ni I and the stabilization of 4 through dispersion forces.