A novel pyrrole fused coumarin based highly sensitive and selective fluorescence chemosensor for detection of Cu2+ ions and applications towards live cell imaging

A novel pyrrole fused coumarin based simple and practicable molecular probe has been synthesized under metal free green conditions which can recognize copper (II) in acetonitrile solvent. The synthesized probe displayed fluorescence quenching through selective binding with Cu2+ over other competitive metal ions. Job's plot, H-1 NMR titration and Mass spectral study revealed that the most abundant species formed when metal to ligand ratio was 1:1. The limit of detection (LOD) for Cu2+ was found to be 11.3 nM or 2 ppb which is significantly lower than the maximum contaminant level (1.3 ppm of Cu), according to United State Environmental Protection Agency (USEPA). The fluorescent sensor was highly cell permeable and illustrated fluorescence 'Turn-Off in presence of Cu2+ ions in fluorescent imaging of human cervical cancer (HeLa) cell.