Luminescent rhenium(I) carbonyl complex with redox noninnocent ONS donor azo-phenol ligand: Synthesis, X-ray structure, photophysical properties and live cell imaging

A new fluorescent rhenium(I) carbonyl complex 1, bearing {Re(CO)3}+ core with ONS donor thioether containing redox noninnocent azo-phenol ligand has been synthesized and characterized. The distorted octahedral geometry of the complex is confirmed by X-ray structure. The complex exhibits low energy emission band at 525 nm with high emission quantum yield (ϕ = 0.115). Cytotoxicity of the complex is studied by MTT method with human breast cancer cell lines (MCF-7) and IC50 value is found to be 23.6 μM. In presence of the complex (10 μM) a bright green fluorescence image of MCF-7 cell lines is observed under fluorescence microscope.