Benzimidazole-based chromogenic chemosensor for the recognition of oxalic acid via counter ion displacement assay in semi-aqueous medium

An azo dye-coupled benzimidazole-based receptor 1 was synthesized and investigated as a receptor for metal ions in semi-aqueous medium. The receptor recognizes Cu2+ with high selectivity over other metal ions. The resultant complex 1·Cu2+ was found to selectively bind oxalic acid via counter ion displacement.