A Selective Naked-Eye and Fluorescent Sensor for the Detection of Cr(III) and Cu(II) Ions and Their Cell Imaging Applications.

A newly synthesised colorimetric and fluorescent chemosensor (P1) was developed for the selective detection of Cr3+ and Cu2+ ions in the presence of various competing cations and anions. The structure of P1 was thoroughly characterized using FT-IR, NMR, high-resolution mass spectra, and single-crystal X-ray diffraction techniques. The 1:1 binding ratio of the probe was verified using Job's plot analysis, and further density functional theory calculations were performed to gain insight into the coordination mode, metal-ligand bonding, and optimized molecular geometry of the complexes. The sensor exhibited detection limits of 1.96 μM for Cr3+ and 7.16 μM for Cu2+. Furthermore, fluorescence imaging studies in HeLa cells demonstrated a significant fluorescence enhancement upon exposure to Cu2+ ions, confirming the effective sensing performance and bioimaging applicability of P1.