Selective detection of fluoride and hydrogen sulfate anions by pyrimidine-based fluorescence chemosensor

The binding and sensing abilities of pyrimidine based fluorescence chemosensor L towards different anions such as F - , Cl - , Br - , I - , NO 3 - , ClO 4 - , H 2 PO 4 - and HSO 4 - have been examined by fluorescence spectroscopy in DMSO-H 2 O (7: 3, v/v). Upon successive addition of various anions to DMSO-H 2 O solutions of L ; quenching in emission fluorescence is observed at 480 nm. Analysis of fluorescence emission changes suggested the formation of 1:1 complex of L with the anions. From the fluorescence binding constant data, it is found that L form strong complexes with F - and HSO 4- ions through H-bonding interactions. The selective response of F - over other halides and HSO 4- amongst other oxo-anions towards L may be explained on the basis of photo-induced electron transfer process.