A highly selective, sensitive and reusable BODIPY based ‘OFF/ON' fluorescence chemosensor for the detection of Hg2+ Ions

Abstract A BODIPY (borondipyrromethane) based fluorescence probe anchored with N,N-bis(2-(pyridin-2-ylmethoxy)ethyl)aniline receptor ( BDPS ) has been designed, synthesized and successfully characterized. It can selectively sense Hg 2+ ion by giving significant emission enhancement at 514 nm over other biologically and environmentally relevant metal ions in CH 3 CN/H 2 O (1:1) medium. The turn-on behaviour of the sensor is due to the metal chelation enhanced fluorescence (MCHEF) effect which has been confirmed by deriving the Job's plot from titration experiment and the high binding constant of 4.19 ± 2.67 × 10 5  M ‐1 between Hg 2+ and BDPS . Furthermore, the sensor can efficiently detect Hg 2+ in a competitive environment upto submicromolar range revealing high selectivity towards Hg 2+ . The sensing probe is reversible on adding excess amount of S 2− to the solution of BDPS pre-incubated with Hg 2+ . Reusability of the probe has been demonstrated successfully by multiple cycles of alternative addition of Hg 2+ ions followed by S 2− ions. Consequently, INHIBIT molecular logic gate can be constructed with the help of OFF-ON-OFF signal on successive addition of Hg 2+ (input 1) and S 2− (input 2) to the probe. Finally, the test paper experiment demonstrates the practical utility of BDPS for the easy and visual detection of Hg 2+ .