A Dual-target Fluorescent Chemosensor for Detecting Indium (III) and Hypochlorite with High Selectivity

A dual-target fluorescent chemosensor BQC (((E)-N-benzhydryl-2-(quinolin-2-ylmethylene)hydrazine-1-carbothioamide) was synthesized for detecting In³⁺ and ClO⁻. BQC displayed green and blue fluorescence responses to In³⁺ and ClO⁻ with low detection limits (0.83 µM for In³⁺ and 2.50 µM for ClO⁻), respectively. Importantly, BQC is the first fluorescent chemosensor capable of detecting In³⁺ and ClO⁻. The binding ratio between BQC and In³⁺ was determined to be a 2:1 through Job plot and ESI-MS analysis. BQC could be successfully utilized as a visible test kit to detect In³⁺. Meanwhile, BQC showed a selective turn-on response to ClO⁻ even in the presence of anions or reactive oxygen species. The sensing mechanisms of BQC for In³⁺ and ClO⁻ were demonstrated by ¹ H NMR titration, ESI-MS and theoretical calculations.