Synthesis and Characterization of 5‐Coordinate Tungsten Hydride Anions: [( t Bu 3 SiNH)( t Bu 3 SiN=) 2 HWR]M

Treatment of ( t Bu 3 SiNH)( t Bu 3 SiN=) 2 WH ( 1 ‐H) with small alkyl anions (RM) afforded tungsten alkyl hydride anions [( t Bu 3 SiNH)( t Bu 3 SiN=) 2 HWR)]M ( 3 ‐(R)M: R=CH 3 , M=Li; R= n Bu, M=Li; R= neo Pe, M=Li; R=CH 2 Ph (Bn), M=K (two isomers); R=CCH, M=Na; R=CH=CH 2 (Vy), M=Li). The saturated alkyl anions 3 ‐(R)M ( 3 ‐(R)M: R=CH 3 , M=Li; R= n Bu, M=Li; R= neo Pe, M=Li; R=CH 2 Ph (Bn), M=K) degraded via apparent 1,2‐RH‐elimination to produce the known [( t Bu 3 SiN=) 3 WH]M ( 2 ‐HM), but the acetylide ( 3 ‐(C 2 H)Na) and vinyl ( 3 ‐(Vy)Li) anions converted to their hydrogenated isomers, [( t Bu 3 SiN=) 3 WVy]Na ( 2 ‐VyNa) and [( t Bu 3 SiN=) 3 WEt]Li ( 2 ‐EtLi), respectively. The structure of 3 ‐( n Bu)Li is reported, and a discussion of tungsten‐hydride coupling constants in t Bu 3 SiX‐ligated (X=O, NH, N) systems is given.