Fast, high-yield synthesis of amphiphilic Ag nanoclusters and the sensing of Hg2+ in environmental samples

Abstract

We report the high-yield (74%) synthesis of Ag₃₀(Capt)₁₈ (abbreviated as Ag₃₀) in a very time-saving fashion (half an hour). The cluster composition was determined by high-resolution mass spectrometry combined with TG analysis, and the structure was probed by 1D and 2D NMR. Interestingly, the nanoclusters can dissolve in water and methanol, as well as in most organic solvents such as ethanol, acetone, acetonitrile, dichloromethane and ethyl acetate with the assistance of acetic acid. Such a good solubility in a range of various polar solvents was not reported previously in nanoclusters’ research and is important for applications. An important result from this work is that Ag₃₀ can sense a low concentration of Hg²⁺ in environmental samples (including lake water and soil solution), indicating that Ag₃₀ can be a potential colorimetric probe for Hg²⁺. The sensing mechanism was revealed to be related to the anti-galvanic reduction process.