We report here the synthesis, X-ray structures, optical and electrochemical properties, fabrication of light-emitting devices, and density functional calculations for indolizino[3,4,5-ab]isoindole (INI) derivatives. Strongly luminescent heterocycles based on the INI unit were synthesized by 1,3-dipolar cycloaddition reactions between pyrido[2,1-a]isoindole (PIS) and acetylene or ethylene derivatives. They are indolizino[3,4,5-ab]isoindoles 2-9 and 14-15, benzo[1',2'-1,2]indolizino[3,4,5-ab]isoindoles 10, pyridazino[4',5':1,2]indolizino[3,4,5-ab]isoindoles 12-13, and 2,3-hydropyridazino[4',5':1,2]indolizino[3,4,5-ab]isoindole-1,4-dione 11. The relative luminescence quantum yield can be as high as 90%. Their reduction and oxidation potentials and high luminescence can make these heterocycles possible alternatives to tris(8-hydroxyquinolinato)aluminum (Alq(3)). The brightness of the light-emitting device reached as high as 10(4) cd/m(2) and indolizino[3,4,5-ab]isoindole 3 emits beautifully blue light. The X-ray crystal structures of INI derivatives were obtained for the first time. The geometries obtained from X-ray data and density functional theory calculations shed more light on an interesting formally antiaromatic 16pi system, which is divided into 10pi and 6pi aromatic systems. We also report a relatively easy protonation of INI, which occurs at a carbon, rather than nitrogen atom.

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We report here the first observation of facilitated anion transfer across the interface between two immiscible electrolyte solutions (ITIES). Complexation behavior between anions and neutral receptors via hydrogen bonding at the 1,2-dichloroethane (DCE)water interface is investigated.Complexation reactions at liquid-liquid interfaces play a fundamental role in biochemical systems such as transmembrane signaling 1 and enzymatic reactions 2 in biological membranes. They are also important in many technological systems from separation chemistry 3 to chemical sensors. 4 To analyze such interfacial complexation mechanisms, electrochemical ion transfer across ITIES facilitated by various ionophores is a useful technique and has been extensively investigated for cations. 5 However, no studies have been reported for anions despite their important role in vivo.Recently, a variety of neutral hydrogen-bonding receptors have been developed, 6 in mimicry of the binding structure of phosphaterecognition membrane proteins. 7 These artificial receptors, however, have been used only in bulk organic solvents except for some application studies. 6b,8 In this report hydrogen-bonding receptors, 1 and 2, 6e are used to study facilitated anion transfer across the DCE-water interface by electrolyte ascending electrode polarography. 9 Examination 10.

The effect of alkyl chain length of chelating reagents on the complexation kinetics of 8-quinolinol (HQ) and 5-alkyloxymethyl-8-quinolinol (HC n Q; n = 1, 2, 3, 5, 8) with transition metal ions (M2+:  Ni2+, Zn2+) at liquid−liquid interfaces is studied by dynamic interfacial tensiometry. A decrease in the dynamic interfacial tension is caused by the interfacial adsorption of a 1:1 complex (M(C n Q)+). The interfacial complexation kinetics for Zn2+ is controlled by the diffusion of ligands from the bulk organic phase to the interface. For Ni2+, the kinetics is also diffusion-controlled for the ligands with short alkyl chains; however, it is controlled by the complexation reaction at the interface for those having longer alkyl chains. The interfacial complexation rate is found to be faster for Zn2+ than for Ni2+, and it correlates closely with the partition coefficient of the ligands. For the reaction-controlled complexation kinetics, a new procedure for calculating the interfacial complexation rate constant (k 1) is proposed, and k 1 values for the reaction with Ni2+ at the heptane−water interface are calculated as 1.7 × 10-5 m s-1 M-1 (1 M = 1 mol dm-3) for HC5Q and 2.2 × 10-5 m s-1 M-1 for HC8Q.

A sensor for nitric oxide is reported that uses a novel redox matching mechanism to induce a resistance change upon binding this important ligand to cobalt.