A novel benzopyran-based colorimetric and near-infrared fluorescent sensor for Hg2+ and its imaging in living cell and zebrafish

A new near-infrared fluorescent probe (OTA-DCM), which contained a conjugated dicyanomethylene-benzopyran structure as the near-infrared fluorophore and dithia-dioxa-monoaza crown ether moiety as the receptor, was developed as a “naked-eye” indicator for Hg2+ with rapid response, good binding constant (1.05 × 104 M−1), high selectivity and sensitivity. Moreover, OTA-DCM was successfully employed in real aqueous samples and fluorescent imaging for detection of Hg2+ in living cells and zebrafish larvae with low cytotoxicity. •A new near-infrared fluorescent probe (OTA-DCM) was developed as a “naked-eye” indicator for Hg2+.•The probe detected Hg2+ with rapid response, good binding constant (1.05 × 104 M−1), high selectivity and sensitivity.•The probe was employed in real aqueous samples and fluorescent imaging for detection of Hg2+ in living cells and zebrafish larvae with low cytotoxicity.