Fluorometric differential detection of Zn2+ and Cu2+ by picolylamine appended pyrimidinone-based receptor: Application in mimicking TRANSFER and INH logic gate

Abstract Herein, we have designed and synthesized pyrimidinone-based dual chemosensor ( DPPA ) containing picolylamine moiety as binding unit. Investigation on the optical property of DPPA revealed fluorescence enhancement at 435 nm with Zn 2+ ion through binding with picolylamine and carbonyl moieties, while Cu 2+ ion was detected through fluorescence quenching at 425 nm and colorimetric changes at 350 nm due to complexation with picolylamine and deprotonation of amide NH group. The detection limit of Zn 2+ and Cu 2+ was calculated to be 10.04 nM and 34.1 nM, respectively. The Job’s plot showed formation of 1:2 and 2:1 binding stoichiometry of DPPA with Cu 2+ and Zn 2+ , respectively. 1 H NMR titration in CD 3 CN revealed downfield shift in methyl groups of N(CH 3 ) 2 and methylene ( CH 2 ) protons of picolylamine chain due to formation of coordinate bonds between Cu 2+ and DPPA , whereas only downfield shift of methylene ( CH 2 ) protons of picolylamine were responsible for complexation with Zn 2+ ions. The complexation mechanisms of DPPA with Cu 2+ and Zn 2+ were also supported by detailed theoretical calculations.