Benzimidazole-based probe as selective and sensitive colorimetric chemosensor for fluorescent detection of Cu 2+ and CN − in ACN/H 2 O medium

A benzimidazole-based probe, a dual-response was designed and synthesized to detect Cu2+ and CN− ions. When bound to Cu2+ ions in ACN/H2O (1:1 V/V), RABP demonstrated a chemosensor mechanism because of the combined action of the internal charge-transfer processes and chelation-enhanced absorbance. Furthermore, the RABP probe successfully identified Cu2+ ion concentrations in the nano molar range in an aqueous system with a detection limit of 6.44 nM, which is significantly lower than the US ecological protection agency’s limit point of about 20 µM. With an upper limit of detection of 3.55 nM, the RABP probes similarly detected CN− ions in aqueous solution. Furthermore, by detecting Cu2+ ions in solutions with a pH range of 5–11 without being impacted by pH, RABP showed its adaptability across a variety of physiological contexts. RABP effectively detected Cu2+ and CN− ions in real water samples also. The Job’s plot confirmed the 1:2 and 1:1 stoichiometries for the RABP+Cu2+ and RABP+CN− complex, respectively.