Five-coordination aluminum complexes: Synthesis, crystal structures and utilization for the construction of substituted guanidines

Insertion of 2,6-iPr2C6H3N(Li)SiMe3 or PhN(Li)SiMe3 to the CN bond of Me2NCN or PhCN afforded the lithium complexes [Li(2,6-iPr2C6H3)NC(NMe2)NC(NMe2)N(SiMe3)]2 (1a) and [Li(PhNC(Ph)NSiMe3)]2 (1b). Complexes 1a and 1b were used as precursors to react with AlCl3 affording [(2,6-iPr2C6H3)NC(NMe2)NC(NMe2)N(SiMe3)]2AlCl (2) and [(PhNC(Ph)NSiMe3)]2AlCl (3), respectively. The structures of 2 and 3 were presented. Both 2 and 3 exhibit good activity to catalyze the addition reaction of arylamines to N,N'-diisopropylcarbodiimide.