‘To kill many birds with one stone’: Addressing half-adder, half-subtractor, demultiplexer, 2-to-4 decoder, comparator, keypad lock with unimolecular system

Abstract

Unimolecular system SBU shows multiple output responses on interaction with Cu2+/F− ions individually and simultaneously. The complexation of Cu2+ with imine (CN) and OH groups results in blue-shift from 332 to 303nm and de-protonation of OH group with F− ions causes red-shift of the absorption maxima from 332 to 405nm. The addition of F− to SBU∩Cu2+ solution or addition of Cu2+ to SBU∩F− solution shifts the absorption maxima from 303 to 374nm or 405–303nm, respectively. Similarly, the complexation of Cu2+ ions, inhibits the ESIPT emission at 512nm with concommitant release of emission at 425nm, whereas F− results in quenching of emission at 512nm up to 10μM, followed by blue-shift to 425nm at >10μM F− ions. The addition of F− to SBU∩Cu2+ solution causes quenching of emission at 512 and 425nm, whereas addition of Cu2+ to complex SBU∩F− solution revives the emission at 425nm 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.