Intriguingly fluorescent glutathione-silver@gold (GSHAg@Au) assembly has been synthesized in aqueous medium under UV light irradiation. The assembly consists of small fluorescent Ag2/Ag3 clusters. There occurs a drift of electron density from Ag(0) to Au(I) within the assembly that provides a long term stability. On vacuum drying of GSHAg@Au assembly, a deliverable solid is obtained that can be re-dispersed in aqueous as well as non-aqueous medium to generate fluorescent solution. Huge fluorescence of the assembly gets quenched in the presence of long chain aliphatic thiols or amines in both mediums. It is interesting to note that although in aqueous medium the extent of thiol or amine induced quenching of the fluorescence of GSHAg@Au increases with the decrease in chain length of the quenchers, in non-aqueous medium the quenching trend is just reversed. The quenched fluorescence of GSHAg@Au assembly can be recovered selectively by Pb(II) in the organic solvent but not in aqueous medium. In aqueous medium, the GSHAg@Au assembly gets ruptured in the presence of thiols or amines, so the fluorescence cannot be restored. However, in non-aqueous medium the favourable solvent-assembly interaction gets disturbed in the presence of thiols or amines due to their pronounced solubility. As Pb(II) interacts with thiols or amines, the electronic interaction between solvent and assembly is restored and hence the fluorescence of the assembly is regenerated. The observed fluorescence ‘Turn Off/Turn On’ phenomenon has been utilized to construct IMPLICATION molecular logic gate with thiols or amines and Pb(II) as binary inputs in organic solvents.

Solvent polarity driven varied interaction of long chain aliphatic thiol or amines with fluorescent assembly

254th National Meeting (2017)

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