Encapsulation of positive ion [Ni(Im)6]2+ in a cage structure based on imidazole sulfate supramolecules self-assemble: Preparation, structure, hirshfeld surface analysis and electrochemical study

•An interesting supramolecular architecture was obtained by simple synthesis method.•The imidazole sulfate [(HIm)2SO4] and water molecules form a cage-like structure.•This anionic water cluster structure can provide the understanding of SO42− in H2O.