The evaluation of the association constant between R-SN and Hg2+
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The effective determination of heavy metals from environmental media is among the most important issues for many industrialized countries. The interaction between RS-N, as novel heavy metal probe, and metal ions was studied. RS-N shows selective color change from colorless to pink in the presence of Hg2+ in methanol/water solvent and the UV–Vis study shows peak at 560 nm. Fluorescence data revealed that the fluorescence enhance of RS-N by Hg2+ dramatically was the result of the formation of [Hg2+]RS-N complex. The effective association constants (K a ) were 3.97 × 105 and 0.204 × 105 M−1 for Hg2+ and Cu2+ to RS-N, respectively. The thermodynamic parameters, enthalpy change (ΔH 0) and entropy change (ΔS 0), were calculated to be −6.431 ± 0.226 kJ/mol and −0.129 ± 0.008 J/K/mol, respectively, according to van’t Hoff equation on the basis of Gibbs free energy (ΔG 0) ranged from −33.8326 to −28.5389 kJ/mol.
KeywordsMercury probe Association constant Fluorescent sensor Copper
The authors acknowledged the financial support by the National Natural Science Foundation of China (no. 21205001) and the Anhui Provincial Natural Science Foundation (no. 1208085MB16).
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