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Unimolecular system SBU shows multiple output responses on interaction with Cu 2+ /F − ions individually and simultaneously. The complexation of Cu 2+ with imine ( C N) and OH groups results in blue-shift from 332 to 303 nm and de-protonation of OH group with F − ions causes red-shift of the absorption maxima from 332 to 405 nm. The addition of F − to SBU∩Cu 2+ solution or addition of Cu 2+ to SBU∩F − solution shifts the absorption maxima from 303 to 374 nm or 405–303 nm, respectively. Similarly, the complexation of Cu 2+ ions, inhibits the ESIPT emission at 512 nm with concommitant release of emission at 425 nm, whereas F − results in quenching of emission at 512 nm up to 10 μM, followed by blue-shift to 425 nm at >10 μM F − ions. The addition of F − to SBU∩Cu 2+ solution causes quenching of emission at 512 and 425 nm, whereas addition of Cu 2+ to complex SBU∩F − solution revives the emission at 425 nm considerably. These multiple output response leads to elaboration of YES, NOT, NOR, INH, AND, XOR and XNOR logic gates and Half-adder, Half-subtractor, 2-to-4 decoder, 1:2 demultiplexer, Magnitude Comparator, complimentary OR/NOR circuit and molecular keypad lock logic circuits. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]