A Swift One-Pot Solvent-Free Synthesis of Benzimidazole Derivatives and Their Metal Complexes: Hydrothermal Treatment, Enzymatic Inhibition, and Solubilization Studies

Three benzimidazole derivatives, 1-(1H-benzimidazol-2-yl)ethanol (HBE), 1H-benzimidazol-2-yl(diphenyl)methanol (BDM) and 1,2-bis(1H-benzimidazol-2-yl)ethane-1,2-diol (BHBED), have been synthesized following the one-pot rapid green protocol. Complexes of benzimidazole derivatives with six 3d transition metals, Cu(II), Mn(II), Zn(II), Fe(II), Co(II), and Ni(II), have been synthesized by free hydrothermal method. The synthesized products have been characterized by FTIR, 1H, and 13C NMR, and mass spectroscopy, and CHN analysis, and 2:1 ligand to metal stoichiometry has been confirmed. The synthesized ligands and metal complexes have been tested for antioxidant potential (DPPH), inhibitory activity including inhibition of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), lipoxygenase (LOX), α-glucosidase. Micellar solubilization of the metal complexes has been studied in sodium dodecyl sulphate (SDS) by UV-Vis spectroscopy and conductivity. The selected complexes of nickel, zinc and cobalt have demonstrated interaction with SDS, and the value of critical micellar concentration increased in all cases.