Photoproduced Fluorescent Au(I)@(Ag2/Ag3)-Thiolate Giant Cluster: An Intriguing Sensing Platform for DMSO and Pb(II)

Synergistic evolution of fluorescent Au(I)@(Ag-2/Ag-3)-thiolate core-shell particles has been made possible under the Sun in presence of the respective precursor coinage metal compounds and glutathione (GSH). The green chemically synthesized fluorescent clusters are giant (similar to 600 nm) in size and robust. Among all the common water miscible solvents, exclusively DMSO exhibits selective fluorescence quenching (Turn Off) because of the removal of GSH from the giant cluster. Again, only Pb(II) ion brings back the lost fluorescence (Turn On) leaving aside all other metal ions. This happens owing to the strong affinity of the sulfur donor of DMSO for Pb(II). Thus, employing the aqueous solution containing the giant cluster, we can detect DMSO contamination in water bodies at trace level. Besides, a selective sensing platform has emerged out for Pb(II) ion with a detection limit of 14 X 10(-8) M. Pb(II) induced fluorescence recovery is again vanished by I- implying a promising route to sense I- ion.