New Schiff bases derived from benzimidazole as efficient mercury-complexing agents in aqueous medium

In this paper, we describe a very fast and efficient synthesis of series of new Schiff bases L1-L5 derived from benzimidazole. It was found that, these compounds react efficiently with mercury ions to afford the corresponding complexes COP1-COP5 in nearly quantitative yield. This reaction takes place in water and in most of the usual solvents. The study of the complexation reaction of L1 with other metal ions has been carried out and shown that L1 can efficiently coordinate with Cu2+ and Co2+. In addition, the reactivity of the benzimidazole Schiff bases has been compared with some reported pyridine analogues and checked with DFT calculations. It has been found that both experimental results and theoretical calculations confirm that the benzimidazole Schiff bases are clearly more reactive than their pyridine analogues. (C) 2019 Elsevier B.V. All rights reserved.