Polypyridyl-imidazole based smart Ru(II) complex mimicking advanced Boolean and Fuzzy logic functions

Abstract

A terpyridyl-imidazole based heteroditopic Ru(II) complex of composition [(phen)2Ru(tpy-Hbzim-dipy)](ClO4)2] (1), where tpy-Hbzim-dipy=4′-[4-(4,5-Di-pyridin-2-yl-1H-imidazol-2-yl)-phenyl]-[2,2′;6′,2″] terpyridine and phen=1,10-phenanthroline is designed and structurally characterized in this work for the construction of multifunctional Boolean and Fuzzy logic devices. The designed complex acts as a red-color emitter and has a free terpyridine moiety which can be coordinated to a cationic guest and an imidazole motif capable of interacting with selective anionic guests through hydrogen bonding. Consequently, modulation of physicochemical properties of the complex by the anionic and cationic guests was examined through different optical channels. The metalloreceptor acts as a chromogenic sensor for F−, AcO−, CN−, and H2PO4− among the anions, while for Fe2+ among bivalent 3d cations in acetonitrile. Based on various output signals with a particular set of anionic and cationic inputs, the complex mimics the functions of four-inputs NOR logic gate and complicated function of memory device. More importantly, we also report the implementation of Fuzzy logic approach to develop an infinite-valued logic system based on either the absorbance or luminescence dependence of the complex upon concentration of different ionic inputs. In conjunction with the experimental investigation, density functional theory (DFT) and time-dependent density functional theory (TD-DFT) studies were also carried out to investigate the structural and electronic properties of the receptor.