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We present electrical transport studies of two ammonium hexafluorometallates of general formula (NH4)3GaxV1−xF6, highlighting the intriguing relationship between structure and electrical and electrochemical properties. Part of this study uses a method adapted to probe the solid-state electrochemical characteristics on individually contacted single crystals. For compound 1, x varies over 0.15 < x < 0.3, and for 2, x varies over 0.3 < x < 0.4, as determined by physical and chemical characterization. Electronically, compounds 1 and 2 are found to be wide bandgap electronic materials at room temperature. Variable temperature electrical measurements on single crystals of 1 and 2 show temperature-activated behavior for both. Within the temperature range probed, possible conduction pathways are discussed in relation to the structure and in comparison to other hexafluorometallates. We show that solid-state electrochemical studies on single crystals of 1 and 2 can probe redox properties of the metal centers in materials with low electrical conductivity, of interest in electrochemical energy storage applications. [ABSTRACT FROM AUTHOR]

A series of flavones (n-F) substituted at the 4′, and 6 positions was prepared, characterised by NMR (1H,13C), HRMS, and studied for liquid crystal properties. The 4′-alkoxy,6-methoxyflavones (4-F–16-F) exhibit varying ranges of nematic and smectic A phases as evidenced by polarised optical microscopy and differential scanning calorimetry (DSC). As the tail length is increased, the smectic phase becomes more prevalent. Smectic phases for (8-F–16-F) were further analysed by powder X-ray diffraction (XRD), and the rate of structural transformations was explored by combined DSC/XRD studies. Flavonol6-F–OHwas also prepared but no mesogenic behaviour was observed. The molecular structures of6-Fand6-F–OHwere determined by single-crystal XRD and help to explain the differences in material properties. Additionally, fluorescence and electrochemical studies were conducted on solutions ofn-F. [ABSTRACT FROM AUTHOR]

Two supramolecular metal complexes [Cu(II)(terpy)(PCP)(NO)] (1) and [Zn(II)(terpy)(NO)] (2) (terpy=2,2′:6′,2″-terpyridine) (PCP = Pentacyanopropenide) were synthesized and structurally characterized by Single-crystal X-ray diffraction. Single-crystal X-ray diffraction revealed that the PCP ligand coordinated to Cu(II) ion through one CN group, and it was absent from the coordination sphere of Zn(II) complex. In complexes ( 1) and ( 2), 1D chain was formed through C1-H1···O1 and C4-H4···O2 hydrogen-bonding interactions, respectively. The crystal structure was further stabilized by π-π stacking interactions. The thermal stabilities of these compounds were investigated. Furthermore, antimicrobial activities of these compounds were investigated against eight types of bacteria. The copper complex exhibited a significant activity against three types of bacteria with minimal inhibitory concentrations (MICs) under one microgram per milliliter. [ABSTRACT FROM AUTHOR]

Antiproliferative bioassay-guided fractionation of the ethanol extract of the stems of Anisocycla grandidieri led to the isolation of the known alkaloids stebisimine (1), (+)-1,2-dehydrotelobine (2), (+)-2'-norcocsuline (3) and puetogaline B (4). Herein, we report the full NMR assignments of all compounds and the X-ray crystallography of single crystals of compounds 1 and 3. Compounds 2 and 3 showed moderate antiproliferative activity against the A2780 human ovarian cancer cell line with IC50 values of 4.1 ± 0.3 and 2.7 ± 0.3 μM, respectively, and they also displayed selective activity toward the H460 (large cell lung cancer), MCF-7 (breast ductal carcinoma), and UACC-257 (melanoma) cell lines. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Three new hydroxyl-functionalized secondary benzyl ammonium salts were synthesized and complexed with dibenzo-24-crown-8. Three [2]semirotaxanes and then their two [2]rotaxanes each with two different stoppers were prepared successfully by reactions of the hydroxyl groups with bulky reagents. X-ray analysis of a single crystal of a [2]semirotaxane confirmed its structure. The formation of the [2]semirotaxanes can be reversibly controlled by adding KPF6 and 18-crown-6 sequentially. These new unsymmetrical [2]rotaxanes afford a way to prepare planar chiral rotaxanes and related supramolecular systems. [ABSTRACT FROM AUTHOR]

In this Letter, we show the phonon dispersion of (CH3NH3)3Bi2I9 single crystals at 300 K measured by inelastic x-ray scattering. The frequencies of acoustic phonons are among the lowest of crystals. Nanoindentation measurements verified that these crystals are very compliant and considerably soft. The frequency overlap between acoustic and optical phonons results in strong acoustic-optical scattering. All these features lead to an ultralow thermal conductivity. The fundamental knowledge obtained from this study will accelerate the design of novel hybrid materials for energy applications. [ABSTRACT FROM AUTHOR]