A coumarin and 1,8-napthyridine conjugated novel molecular hybrid: Synthesis, DFT insights and unveiling the selective fluorescent sensing of Hg ions with live-cell imaging application.

Herein, we have used a simple synthetic strategy to access a novel non-sulfur fluorescent molecular probe coumarin and 1,8-napthyridine conjugated probe DNCS. The developed probe has great selectivity and sensitivity for detecting Hg ions. Our photophysical properties evaluation for the synthesized probe with different metal ions (Ba, Al, Ca, Bi, Ce, Cd, Cu, Sr, Co, Fe, Cr, Fe, Mn, Hg, Zn, Pb, Ni, and Sn) unveiled the very selective and sensitive fluorescence sensing behavior with Hg ions in the energy window of near UV and visible light radiation in an organic aqueous solvent mixture (EtOH and water). The limit of detection (LOD) of 9.04 x10 M and binding constant of 2.56 × 10 M were obtained for the probe DNCS with Hg ions, and 1:1 stoichiometric complexation. Our bioimaging experiments demonstrated that the developed probe exhibited fluorescent sensing behaviors towards Hg ions with HCT 116 cells. Moreover, the current studies present the electronic properties of the DNCS probe computed through DFT computation studies at the B3LYP/6-311G(d,p) level of theory. We are confident that the developed fluorescent probe has the potential for the efficient fluorometric detection of Hg ions and plays a significant role in environmental and human health protection.