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

Abstract

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 red-emitting fluorescence (located at ∼600 nm) and ultrasmall particle sizes (∼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⁺.