Nickel Promoted Condensation of Acetamide and Benzonitrile for the Synthesis of an Imidoylamidine (N-NacNac) via Stable Imidoylamide Intermediate

Abstract

The acetamide-benzonitrile and benzonitrile self-condensation reactions promoted by nickel­(II) hydroxy dimer 1, [Ni2(tBuDPA)2(μ-OH)2]­(ClO4)2 (tBuDPA = bis­(2-methylpyridine)tert-butylamine), for the production of imidoylamidine (IDA) ligand, N-benzimidoylbenzamidine, is investigated by UV–vis, ESI-MS, FT-IR, elemental analysis, and single crystal XRD. An imidoylamide (IDD) intermediate 2, [Ni­(tBuDPA)­(IDD)]­ClO4, is trapped and fully characterized, and its reactivity with benzonitrile is confirmed. Kinetic studies gave insight into the mechanism for the formation of 2 and its conversion to 3, [Ni­(tBuDPA)­(IDA)]­ClO4. Formation of 2 is dependent on acetamide concentration, and its reactivity is affected by protic solvents, water, and methanol.