Triazole-linked pyrene appended xylofuranose derivatives for selective detection of Au3+ ions in aqueous medium and DFT calculations

The sugar-modified simple fluorometric sensors 1 and 2 for detection of Au3+ in the aqueous acetonitrile have been reported. The sensors are double-responsive (absorbance and fluorescence) selective Au3+ sensors in CH3CN-H2O (1:1, v/v). Both the sensors exhibited remarkable selectivity and excellent sensitivity (limit of detection values are 0.53 mu M for 1 and 0.83 mu M for 2). The stoichiometry of each complex was established by Job's plot and supported by the ESI-mass spectrum of the complex. Finally, the coordination mode of each sensor with Au3+ ions was supported by DFT calculations in CH3CN-H2O (1:1, v/v) medium. The energy-optimized structures of 1-Au3+ and 2-Au3+ suggested that sensors 1 and 2 followed different binding modes with Au3+ ions in the aqueous acetonitrile medium, which account for the ESI-MS spectra of the complexes. Interestingly, we observed that fluorometric sugar derivatives 1 and 2 did not show any specific selectivity towards metal ions in CH3CN.