Aluminium(III) amidinates formed from reactions of `AlCl' with lithium amidinates

The disproportionation of AlCl(THF)_n (THF is tetrahydrofuran) in the presence of lithium amidinate species gives aluminium(III) amidinate complexes with partial or full chloride substitution. Three aluminium amidinate complexes formed during the reaction between aluminium monochloride and lithium amidinates are presented. The homoleptic complex tris(N,N′‐diisopropylbenzimidamido)aluminium(III), [Al(C₁₃H₁₉N₂)₃] or Al{PhC[N(i‐Pr)]₂}₃, (I), crystallizes from the same solution as the heteroleptic complex chloridobis(N,N′‐diisopropylbenzimidamido)aluminium(III), [Al(C₁₃H₁₉N₂)₂Cl] or Al{PhC[N(i‐Pr)]₂}₂Cl, (II). Both have two crystallographically independent molecules per asymmetric unit (Z′ = 2) and (I) shows disorder in four of its N(i‐Pr) groups. Changing the ligand substituent to the bulkier cyclohexyl allows the isolation of the partial THF solvate chloridobis(N,N′‐dicyclohexylbenzimidamido)aluminium(III) tetrahydrofuran 0.675‐solvate, [Al(C₁₉H₂₇N₂)₂Cl]·0.675C₄H₈O or Al[PhC(NCy)₂]₂Cl·0.675THF, (III). Despite having a twofold rotation axis running through its Al and Cl atoms, (III) has a similar molecular structure to that of (II).