Synthesis and Structures of Novel Phenyl-Bridged Bis(1-azaallyl) Alkali-Metal Compounds

The series of dilithium bis(1-azaallyl) compounds [{ o -{N(SiMe 3 )C(R)C(H)} 2 C 6 H 4 }{Li 2 (TMEDA) 2 }] (R = Bu t ( 1 ), Ph ( 3 )), [{ m -{N(SiMe 3 )C(Bu t )C(H)} 2 C 6 H 4 }{Li 2 (TMEDA) 2 }] ( 5 ), and [{ p -{N(SiMe 3 )C(Bu t )C(H)} 2 C 6 H 4 }{Li 2 (TMEDA) 2 }] ( 6 ) have been prepared by addition of the Li−C bond of [{ o-/m-/p -(CHSiMe 3 ) 2 C 6 H 4 }{Li 2 (TMEDA) 2 }] to a nitrile RCN (R = Bu t, Ph) followed by a 1,3-shift of the SiMe 3 group. Likewise, the addition of [{ o -(CHSiMe 3 ) 2 C 6 H 4 }{Li 2 (TMEDA) 2 }] to an isonitrile Bu t NC followed by 1,2-trimethylsilyl migration yielded [{ o -{N(Bu t )C(SiMe 3 )C(H)} 2 C 6 H 4 }{Li 2 (TMEDA) 2 }] ( 4 ). The dilithium compounds 1 and 6 can be further transferred to their potassium analogues [{ o -{N(SiMe 3 )C(Bu t )C(H)} 2 -C 6 H 4 }{K 2 (TMEDA)}] n ( 2 ) and [{ p -{N(SiMe 3 )C(Bu t )C(H)} 2 C 6 H 4 }{K 2 (THF) 3 }] 2 ( 7 ) by reaction with Bu t OK. The structures of compounds 2 − 5 and 7 have been determined by X-ray structural analyses.