Silver–NHC complex as a fluorophore for the selective detection of sulphide (S2−) anions†

Abstract

Silver–NHC complexes have been recently reported for a wide variety of applications in the fields of catalysis and medicine. The key is the presence of a structurally versatile and tunable N-heterocyclic carbene (NHC) ligand on the Ag–NHC complex, which is useful to produce interesting properties. This work explores the potential of a silver-1,3,4,5-tetraaryl N-heterocyclic carbene (Ag–NHC) complex as a fluorophore for selective sensing of anions. Interestingly, the synthesised Ag–NHC complex was very selective for sulphide (S²⁻) ions even in the presence of other anions. The limit of detection (LOD) for the sensing was found to be 0.12 μM. The mechanism involved in the sensing process was studied by fluorescence and ¹H-NMR studies. The potential of the Ag–NHC complex to sense S²⁻ anions in real-world conditions was tested using water samples.