Bulky formamidinate complexes of lithium: the first examples of ƞ²:ƞ¹-C=N,N' metal amidinate coordination

Abstract

The lithium complexes [Li{N(Ar)C(H)N(Ar)}(pmdeta)], where Ar = 2,6-R₂C₆H₃ (R = Me (1), Et (2) and iPr (3)) and pmdeta = N,N,N’,N’’,N’’-pentamethyldiethylenetriamine, have been synthesised and their solid state structures determined by X-ray methods. Compounds 1–3 comprise a Li(pmdeta) centre coordinated by a bulky formamidinate in either the E-syn or E-anti isomeric form. The structures of compound 3 and one unique molecular unit of compound 1 (E-anti isomer) display coordination of the pendant amidinate imine, and can therefore be considered the first examples of ƞ²:ƞ¹-CQN,N’ metal amidinate coordination.