Microwave-induced synthesis of a new benzodiazepinone based chemosensor in chloroform under thermal agitation: a potential fluorescent sensor for multi-signaling detection of metal ions

Abstract

A new fluorescent sensor 5, 10-dihydro-11H-pyrido [3, 2-b][1,5] benzodiazepin-11-one (L) has been synthesized and characterized using conventional spectroscopic techniques. The receptor showed large fluorescence quenching effect with transition metal ions like Ni2+, Co2+, Cu2+ and Fe3+ via internal charge transfer (ICT), and with a detection limit at ppm level. The quenching constant was determined using Stern-Volmer plot. UV–vis titrations of L with selected divalent and trivalent metal ions like Ni2+, Co2+, Cu2+, Pb2+, Cr3+, and Al3+ exhibits specific interaction with red shifts in absorption wavelength. The binding stoichiometry of L with divalent metal ions in the ratio of 4:1 was determined using the Job’s plot. The experimental result of UV–vis absorption of L was found to be in good agreement with the calculated data obtained by Density functional theory (DFT) method. As a representative example, the TD-DFT calculations were used to explain the sensing ability of L towards Cu2+ ion.