Dihydroquinazolinone based turn-off fluorescence sensor for detection of Cu2+ ions

A strategy for the synthesis of a dihydroquinazolinone derivative, 2-(pyridine-2-yl)-2,3-dihydroquinazolin-4(1H)-one and its application in selective recognition of Cu2+ ions has been developed. The sensor shows turn-off type paramagnetic fluorescence quenching towards Cu2+ ions. The binding constant (K-a) of Cu2+ ions with the sensor was found to be 8.02 x 10(4) M-1 and binding stoichiometry was determined to be 1:1 based on the Job's plot analysis. The sensor can detect up to nanomolar (0.1 nM) level of Cu2+ ions from tap water. The single crystal of the QZP center dot Cu2+Cl center dot H2O complex was characterized using X-ray diffraction and the paramagnetic nature of Cu2+ was manifested by electron spin resonance (ESR) spectroscopy. (C) 2016 Elsevier Ltd. All rights reserved.