Rhodamine-2-thioxoquinazolin-4-one conjugate: A highly sensitive and selective chemosensor for Fe3+ ions and crystal structures of its Ag(I) and Hg(II) complexes

A rhodamine-2-thioxoquinazolin-4-one derivative (R1) has been synthesized by an addition-elimination reaction of rhodamine 6G ethylenediamine with methyl 2-isothiocyanatobenzoate, which exhibits high selectivity and sensitivity as a fluorescent sensor toward Fe3+ under physiological conditions. Moreover, R1 could sense Fe3+ by naked eye with a color change from colorless to yellow. To test the practical use of the probe, the determination of Fe3+ in real water samples was evaluated. The application of the fluorescent sensor in monitoring intracellular Fe3+ in glioma cell line U251 has also been demonstrated. In addition, single crystal structures of R1 center dot 1 center dot 5H(2)O center dot 0 center dot 5CH(3)CN, as well as the possible intermediate of R1 with Ag+ and Hg2+ ions were reported. (C) 2016 Elsevier B.V. All rights reserved.