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Four iridium(III) complexes (1–4) with sulfur-containing phenylpyridazine ligands were successfully synthesized and characterized. The structure of complex 3 was further confirmed by single X-ray structural analysis. These complexes showed strong green phosphorescence at room temperature with peak wavelengths ranging from 524 to 539 nm in CH2Cl2 solution. These complexes exhibited medium quantum yields of 42 ~ 61% in PMMA films with lifetimes of 1.58 ~ 3.26 μs. These complexes also exhibited good thermal stability with Td > 275 °C. The phosphorescent OLEDs were fabricated using complexes 1 and 2 as dopants. The device using complex 2 displayed good performances with the maximum luminance, current efficiency, power efficiency and external quantum efficiency of 8913 cd m−2, 44.2 cd A−1, 30.7 lm W−1 and 11.8%, respectively. These results indicate excellent application prospects of these iridium(III) complexes as efficient phosphors in OLEDs. [ABSTRACT FROM AUTHOR]

The interactions between crown ether ligands (14-crown-4, 14C4; 4,4,5,5-tetramethylbenzo-14-crown-4, BC4H12-14C4; 4,4,5,5,9,9,10,10-octamethyl-14-crown-4, C8H24-14C4; dibenzo-14-crown ether-4, DB14C4) and alkaline and alkaline earth metal ions (Li+, Na+, Mg2+) were investigated using density functional theory modeling at the M062X/def2SVP and def2TZVP level. The condensed softness analysis of crown ethers, a condensed Fukui function, a condensed dual descriptor, and frontier molecular orbital theory were used to analyze the reactivities of the complexes. The complex stability was analyzed in terms of the binding energies, standard Gibbs free energy of formation, and energy decomposition of the interaction in aqueous solution. The results show that the active sites were mainly located at the carbon atoms of the benzene ring and oxygen atoms. The reactivities of DB14C4 and BC4H12-14C4 are higher than those of 14C4 and C8H24-14C4. The electrostatic interaction is the principal factor determining the stability of the complexes. The complexes containing Li+ has the greatest stability in aqueous solution among the complexes containing Li+, Na+, and Mg2+. BC4H12-14C4 shows selective adsorption toward Li+ in a mixed solution of Li+, Na+, and Mg2+. To evaluate the stability of complexes containing Mg2+, the solvent effect must be accurately described. An energy decomposition analysis was used to evaluate the stability of complexes containing Li+, Na+, and Mg2+, and the solvent effects were considered. [ABSTRACT FROM AUTHOR]

Quaternary ammonium densely functionalized octa-benzylmethyl-containing poly(arylene ether ketone)s (QA-OMPAEKs) with ion exchange capacities (IECs) ranging from 1.23 to 2.21 mmol g−1 were synthesized from: (1) Ullmann coupling extension of tetra-benzylmethyl-containing bisphenol A; (2) condensation polymerization with activated dihalide in the presence of K2CO3; (3) selective bromination using N-bromosuccinimide; and (4) quantitative quaternization using trimethylamine. Both smallangle X-ray scattering (SAXS) and transmission electron microscope (TEM) characterizations revealed distinct nano-phase separation in QA-OMPAEKs as a result of the dense quaternization. The QA-OMPAEK-20 with an IEC of 1.98 mmol g−1 exhibited a high SO42− conductivity of 11.4 mS cm−1 and a low VO2+ permeability of 0.06×10−12 m2 s−1 at room temperature, leading to a dramatically higher ion selectivity than Nafion N212. Consequently, the vanadium redox flow battery (VRFB) assembled with QA-OMPAEK-20 achieved a Coulombic efficiency of 96.9% and an energy efficiency of 84.8% at a current density of 50 mA cm−2, which were much higher than those of the batteries assembled with Nafion N212 and a home-made control membrane without distinct nano-phase separation. Therefore, ion segregation is demonstrated to be a strategical route for the design of high performance anion exchange membranes (AEMs) for VRFBs. [ABSTRACT FROM AUTHOR]

Two novel cyclometalated iridium(III) complexes, Ir(pcl)(pic) and Ir(pcl)(fpic) (pcl: 3-phenylcinnoline, pic: picolinic acid, fpic: 5-fluoro-2-picolinic acid) were synthesized and characterized by FTIR, H NMR spectroscopy, UV-vis, PL, and MALDI-TOF. These two Ir-complexes geometry were predicted using the Sparkle/PM6 model and suggested to a chemical environment of very low symmetry around the Ir ions ( C). The PL spectrum of Ir(pcl)(pic) and Ir(pcl)(fpic) indicated that these complex belonged to red light emission, and maximum emission wavelength located at 647 and 641 nm, respectively. Most importantly, the effects of different solvents on their photoluminescent properties were detailed investigated. The results indicated that the polarity of solvent played an important role for their emission spectra. With introducing fluoro group to the pyridyl ring, the maximum emission wavelength of Ir(pcl)(fpic) was blue shifted about 6 nm, and the quantum yield was slightly higher than that of Ir(pcl)(pic). In addition, the thermal properties of these two Ir-complexes were measured by TGA, and results indicated that they had relative good thermal properties. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A new cyclometalated iridium(III) complex, Ir(ppz)(dtp) ( Ir1) (ppzH = 4-phenylphthalazinone, dtp = diethyl dithiophosphate), has been synthesized and characterized by single-crystal X-ray diffraction. The photoluminescence spectrum of Ir1 shows an emission maximum at 597 nm and its quantum yield is ca. 0.072. Complex Ir1 exhibits a strong and fast decrease of emission upon addition of Ag in aqueous media. The ratio of Ir1 responding to Ag was determined to be 1:1 by UV-Vis absorption and phosphorescent emission measurements. Complex Ir1 is a highly selective chemosensor for Ag over other transition metal ions. [ABSTRACT FROM AUTHOR]