Multidentate polymers stabilized water-dispersed copper nanoclusters: facile photoreduction synthesis and selective fluorescence turn-on response

Using bifunctional thiol-based multidentate polymers {poly(acrylic acid)-graft-mercaptoethylamine} as stabilizers and CuCl2 as the precursor, water-dispersed copper nanoclusters (CuNCs) were prepared by a facile photoreduction method. Upon UV irradiation (365 nm, 8 W) for 0-180 min, the appearance and evolution of fluorescence emission spectra were observed. The prepared CuNCs exhibited bright redemitting fluorescence (located at similar to 600 nm) and ultrasmall particle sizes (similar to 0.8 nm). Different synthesis conditions (irradiation time, pH and [Cu2+]/[-COOH]) were involved to evaluate corresponding effects on spectra of CuNCs. Moreover, experimental results indicated chelating reagents treated CuNCs showed selective fluorescence turn-on responses to Cu2+, compared with other metal ions, exhibiting promising use as a novel CuNCs-based OFF-ON fluorescence probe of Cu2+.