Polypyridyl-imidazole based Os(II) complex as optical chemosensor for anions and cations and multi -readout molecular logic gates and memory device: Experimental and DFT/TDDFT study

A monometallic Os(II) complex of composition, [(bpy))2Os(II)(phen-Hbzim-tpy)](ClO4)(2), where phen-Hbzim-tpy = 2444 (2,6-di( pyridin-2-yl)pyridine-4-yl)pheny1)-1H-imidazole[4,5-f] [1,10]phenanthroline and bpy = 2,2'-bipyridine, containing a free terpyridine site for cationic guest and an imidazole moiety for the anionic guest, has been designed for the fabrication of multifunctional logic circuits. This complex acts a red-color emitter and effective bifunctional optical chemosensor for F-and CN-as well as Fez' and Cu2+ ions. The anion and cation sensing properties of the metalloreceptor have been thoroughly investigated in solution through different channels such as absorption, steady state and time-resolved emission spectroscopic methods and by square wave voltammetric technique. On the basis of the absorption, emission and electrochemical responses with specific set of anionic and cationic inputs, the present metalloreceptor finds its ability to mimic the logic functions of two-inputs INHIBIT, IMPLICATION, and OR logic gate as well as four inputs NOR logic behavior. Moreover, the complex can mimic sequential Boolean logic functions capable of integrating into Writing-Reading-Erasing-Reading combinational circuit for molecular-level information processing. To gain a deeper insights about the structural as well as spectral aspects of the complex, theoretical calculations have also been performed employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT). (C) 2015 Elsevier B.V. All rights reserved.