Carbazole phenylthiosemicarbazone-based ensemble of Hg2+ as selective fluorescence turn-on sensor toward cysteine in water

A carbazole-phenylthiosemicarbazone-based open chemosensor has been designed and synthesized, which exhibits high selectivity toward Hg2+ by forming a 1:1 complex. In its Hg2+ensemble, it is reported as a highly sensitive and selective probe for the detection of mercapto biomolecules in aqueous solution. The addition of Cys (Cysteine) to a 99% aqueous solution of carbazole–phenylthiosemicarbazone–Hg2+ ensemble resulted in a rapid and remarkable fluorescence OFF–ON (emission at 436 nm). The IMP logic gate has also been generated by choosing Hg2+ and Cys as input and by monitoring the output signal at 436 nm that originates from the emission spectra of chemosensor in the presence of Hg2+.