Synthesis and crystal structures of sterically hindered lithium-1-azaallyls and a diazahexatriene

The lithium-1-azaallyl complexes [LiN(Ar)C(R)CHR′(D)] 1 and the diazahexatriene 2 were obtained in moderate yields from LiCHR2 or LiCH(R)Ph(tmen) and ArNC [Ar=C6H3(Pri2-2,6) or C6H3(But2-2,5)]. All compounds were characterized by NMR spectroscopy and single crystal X-ray crystallography. 1b-1d were found to be monomeric in the solid state with 1b adopting an unusual anti-conformation.