Anion and Temperature Responsive Molecular Switches Based on Trimetallic Complexes of Ru(II) and Os(II) That Demonstrate Advanced Boolean and Fuzzy Logic Functions

Anion- and temperature-induced alteration of the photoredox behaviors of our recently reported trimetallic complexes was carried out to fabricate potential molecular switches. The triads [(phen)₂Ru(d-HIm-t)M(t-HIm-d)Ru(phen)₂]⁶⁺ (phen = 1,10-phenanthroline, d-HIm-t = heterotopic bipyridine-terpyridne type bridging ligand, and M = Ru^II and Os^II) possess two acidic imidazole NH protons that upon interaction with anions give rise to considerable changes in their photophysical and electrochemical behaviors. Red-shifts of the absorption and emission maximum and a decrease in the M³⁺/M²⁺ potential occur when the triads are treated with basic anions. In fact, the triads can function as triple-channel sensors for F^-, AcO^-, CN^-, OH^-, and H₂PO₄^- in acetonitrile and as selective probes for CN^- and SCN^- in water. The equilibrium constants for the receptor-anion interaction are on the order of 10⁶ M^-1, while the limit of detection was on the order of 10^-9 M. Temperature plays a key role in the luminescence properties of the triads by adjusting the energy barrier between the emitting triplet metal-to-ligand charge transfer and non-emitting triplet metal-centered levels. A decrease in temperature leads to increases in the emission intensity and lifetime of the triads displaying the "on state", whereas an increase in temperature leads to a decrease in their emission characteristics and thus indicates the "off state" and that the process is fully reversible. In essence, the triads could function as potential switches on the basis of the reversible change in their spectral and redox behaviors under the influence of anion, acid, and temperature. The most important outcome of this study is mimicking several advanced Boolean and fuzzy logic functions by utilizing the spectral response of the triads upon the action of said external stimuli.

New amide based iridium(iii) complexes: synthesis, characterization, photoluminescence and DFT/TD-DFT studies

The photophysical properties of new iridium complexes have been investigated depending on various solvents and substituents and DFT/TD-DFT studies have supported observed optical data.

Recent advances in 1,10-phenanthroline ligands for chemosensing of cations and anions

This review encompasses and highlights recent developments of 1,10-phenanthroline ligands behaving as a customized moiety used in recognition and sensing of cations and anions.

A highly selective and sensitive turn-on chemodosimeter for hypochlorous acid based on an iridium(III) complex and its application to bioimaging

A novel and easily accessible luminescent iridium(iii) complex [Ir(tpy)2(N^N)]PF6 (, tpy = 2-(p-tolyl)pyridine, N^N = 4-[(4-amino-3-nitrophenoxy)-methylene]-4'-methyl-2,2'-bipyridine) for the sensing of HOCl has been designed and synthesized. The detection strategy is based on the HOCl-promoted cleavage of the PET quenching 4-amino-3-nitrophenyloxy moiety of the weakly emissive complex , which gives rise to a highly luminescent complex [Ir(tpy)2(N^N')]PF6 (, N^N' = 4-hydroxymethyl-4'-methyl-2,2'-bipyridine). Comparisons of the absorption, emission and mass spectra of in the absence and presence of HOCl have all confirmed the transformation of to . Titration and competition experiments have revealed high sensitivity and high selectivity of for HOCl, respectively. Significantly, the feasibility of the sensor under physiological conditions enables the successful luminescent imaging of HOCl in HeLa cells.

Fluorometric sensor based on bisterpyridine metallopolymer: detection of cyanide and phosphates in water

A poly(ethylene glycol) (PEG) decorated bis(terpyridine) zinc coordination polymer acts as an anion-responsive material in 100% aqueous solution. Depending on the binding and association constants to Zn(II), the addition of different anions leads to increased emission intensity and/or a shift of the emission wavelength. The sensor was addressed with a collection of common salts to survey the selectivity of the emission response. Phosphate and cyanide, representing the strongest anion binding to zinc(II), were detected even in the presence of other ions in tap water. Biologically relevant phosphates such as diphosphates and adenosine-5'-triphosphate (ATP) also produced a strong response. Because the binding constants with Zn(II) are very high, anion concentrations in the range of 10(-6) to 10(-7) M are sufficient.