Ba-MOFs with tetrazole-based acetic acids: unusual configuration, novel topology and high proton conductivity.

Metal-organic frameworks (MOFs) as proton-conductive materials have attracted increasing attention due to their applications in proton-exchange membrane fuel cells. While the majority of the MOFs are based on transition metals, group II metals with unusual configurations have received relatively less attention. In this work, we selected three tetrazole-based acetic acids, N,N-di(2-carboxymethyltetrazol-5-yl)amine (H2L1), 1,3,5-tri(2-carboxymethyltetrazol-5-yl)benzene (H3L2), and 4,5-di(tetrazol-5-yl)imidazolylacetic acid (H3L3), as ligands and prepared three MOFs with barium(ii) ions: [Ba2(L1)2(H2O)5]·2H2O (1), (Me2NH2)[Ba(L2)(H2O)]·3H2O (2), and [Ba3(µ2-H2O)(L3)2(H2O)3]·2H2O (3). Ba-MOFs have been unambiguously characterized by elemental, FT-IR spectroscopy and single-crystal X-ray diffraction analyses. In the solid state, 2D MOF 1 with two nine-coordinated Ba(ii) centers shows a rare hula hoop-like geometry at the Ba1 atom and a distorted tricapped trigonal prismatic geometry around the Ba2 one. Unusual sphenocorona geometry is also found in MOF 2 with a ten-coordinated Ba(ii) ion. In MOF 3, three different Ba(ii) ions coexist with two nine-coordinated Ba1 and Ba2 displaying a muffin-like configuration and a distorted tricapped trigonal prism geometry, respectively, and an eight-coordinated Ba3 having a distorted biaugmented trigonal prism geometry. In addition, MOF 2 exhibits an unprecedented trinodal 3,7,7-connected 3D network with the Schläfli symbol (37·46·52·62·74)(37·46·52·63·73)2(63) and MOF 3 displays a novel trinodal 4,5,9-connected 3D framework with the Schläfli symbol (421·615)(45·6)(48·62). Due to the presence of extensive hydrogen bonded networks consisting of dimethyl ammonium and water molecules in the 1D channels, MOF 2 shows a high proton conductivity of 4.47 × 10-3 S cm-1 at 85 °C and 98% relative humidity (RH).

A PEG/copper(i) halide cluster as an eco-friendly catalytic system for C-N bond formation.

The catalytic activities of eight copper(i) halide clusters assembled from copper(i) halide and ferrocenyltelluroethers, 1-8, were investigated in C-N formation under various conditions. A catalytic procedure using poly(ethylene glycol) (PEG-400) as a greener alternative organic solvent has been developed. The PEG-400/5 system can achieve 99% targeted yield with a mild reaction temperature and short reaction time. After the isolation of the products by extraction with diethyl ether, this PEG-400/cluster system could be easily recycled. Spectroscopic studies elucidate a stepwise mechanism: firstly, proton-coupled electron transfer (PCET) involving the transfer of an electron from Cu+ and a proton from imidazole results in the formation of a labile penta-coordinated Cu2+ and aryl radical; the following effective electron transfer from the ferrocene unit reduces Cu2+ and forms the target product; finally, the ferrocenium unit is reduced by the I- anion. The merits of this eco-friendly synthesis are the efficient utilization of reagents and easy recyclability.

Three sra topological lanthanide-organic frameworks built from 2,2'-dimethoxy-4,4'-biphenyldicarboxylic acid.

Three 3D lanthanide­organic frameworks (LOFs), [LnL(HCO2)(DMF)]n (Ln = Eu (1), Gd (2), Dy (3); H2L = 2,2'-dimethoxy-4,4'-biphenyldicarboxylic acid), have been prepared by the solvothermal reaction of Ln(NO3)3·6H2O and H2L in DMF­H2O mixed solvent. Crystallographic data show that LOFs 1­3 are isomorphous and crystallize in the orthorhombic space group Pna21. Each Ln(III) is eight-coordinated to four O atoms from four L2− ligands, one O atom from the DMF molecule and three O atoms from HCO2−. The adjacent Ln(III) ions are linked by the carboxylate groups of the L2− ligands and HCO2− to form a 1D inorganic rod-shaped [Ln(CO2)2(HCO2)]n chain as a secondary building unit (SBU). The infinite 1D chains are interconnected by the biphenyl groups, giving rise to a 3D framework along the c axis. LOFs 1­3 are the first neutral Ln-carboxylate/HCO2− chain-based sra-nets. 1 exhibits characteristic luminescence of Eu3+ upon 343 nm excitation. The investigation of magnetic properties shows very weak ferromagnetic interactions (J = 0.0092(3) cm−1) between Gd(III) ions in 2 with a Gd­O­Gd bridging angle of 125.6(1)°, and θ = −1.9(2) K in 3 due to thermal depopulation of the Stark levels of Dy(III) ions and/or the possible antiferromagnetic interactions between Dy(III) ions in contrast to the single-ion behavior observed in 1.

Electrostatic and non-covalent interactions in dicationic imidazolium-sulfonium salts with mixed anions.

A series of thioether-functionalised imidazolium salts have been prepared and characterized. Subsequent reaction of the thioether-functionalised imidazolium salts with iodomethane affords imidazolium-sulfonium salts composed of doubly charged cations and two different anions. Imidazolium-sulfonium salts containing a single anion type are obtained either by a solvent extraction method or by anion exchange. The imidazolium-sulfonium salts undergo a methyl-transfer reaction on exposure to water, giving rise to a new, singly charged imidazolium salt with iodide introduced at the 2-position of the imidazolium ring. Crystal structures of some of the imidazolium-sulfonium salts were determined by X-ray crystallography providing the topology of the interactions between the dications and the anions. Electrospray ionization mass spectrometry and quantum-chemical calculations were used to rationalise the relative strength of these interactions.

A novel dumbbell-like polyoxometalate assembled of copper(II)-disubstituted monovacant keggin polyoxoanions with a tetranuclear copper cluster.

A dimeric Keggin polyoxometalate, [Cu(bpy)(µ2-OH)]4[(H2O)(bpy)2HPW11Cu2O39]2·2CH3CH2OH·10H2O (1), constructed from two dicopper(II)-substituted monovacant Keggin polyoxoanions bridged by a Cu4 cluster, has been hydrothermally synthesized. Magnetic analysis indicates predominantly an antiferromagnetic interaction between copper(II) centers. Compound 1 also shows very high catalytic activity for the esterification of phosphoric acid with equimolar lauryl alcohol to monoalkyl phosphate ester.

A novel 2-D coordination polymer constructed from high-nuclearity waist drum-like pure Ho48 clusters.

A novel 2-D coordination polymer constructed from high nuclearity nanosized Ho48 clusters was synthesised and structurally characterized using single-crystal X-ray analysis. The Ho48 cluster core with a charming waist drum-like structure was templated by CO3(2-) ions, and bridged by Ho-N bonds to get a 2-D coordination polymer.

A new "fully reduced" polyoxovanadate constructed from nanosized triangle-shaped [V(III)3V(IV)18P6O60(DACH)3]}9- cluster anions exhibiting ferrimagnetic interactions.

Magnetic personality: A pentavalent vanadium source was employed to prepare the largest highly reduced polyoxovanadate cluster by virtue of the reducing power of 1,2-diaminocyclohexane under hydrothermal conditions. The new non-classical triangle-shaped cluster shows good catalytic selectivity for the oxidation of styrene and exhibits ferrimagnetic interactions that could make it a promising magnetic material.

[6,13-Bis(2,4-dichloro-benzo-yl)-5,7,12,14-tetra-methyl-dibenzo[b,i][1,4,8,11]tetra-aza-cyclo-tetra-decinato- κ4N]nickel(II) acetone monosolvate.

In the title complex, [Ni(C36H26Cl4N4O2)]·C3H6O, two 2,4-dichloro-benzoyl groups are grafted onto the methine groups of the Ni(II) complex Ni(tmtaa) (H2tmtaa = 5,7,12,14-tetra-methyl-4,11-dihydro-dibenzo[b,i][1,4,8,11]tetra-aza-cyclo-tetra-decine). The complex has the shape of a saddle. The Ni atom is tetra-coordinated by the four N atoms of the macrocycle, forming a slightly tetra-hedrally distorted square-planar geometry. The metal is displaced by 0.0101 (8) Šfrom the N4 mean plane. The aromatic rings of the 2,4-dichloro-benzoyl groups form dihedral angles of 87.1 (2) and 82.1 (2)° with the N4 mean plane.

2-(2,4-Difluoro-phen-yl)-5-nitro-pyridine.

In the title mol-ecule, C(11)H(6)F(2)N(2)O(2), the benzene and pyridine rings form a dihedral angle of 32.57 (6)°. The nitro group is tilted with respect to the pyridine ring by 12.26 (9)°. An intra-molecular C-H⋯F hydrogen bond is present. In the crystal, mol-ecules inter-act through π-π stacking inter-actions [centroid-centroid distances = 3.7457 (14) Å], forming columnar arrangements along the b axis. The crystal packing is further enforced by inter-molecular C-H⋯O and C-H⋯N hydrogen bonds.

3-{[Bis(pyridin-2-ylmeth-yl)amino]-meth-yl}-2-hy-droxy-5-methyl-benz-aldehyde.

In the title compound, C(21)H(21)N(3)O(2), the pyridine rings and the benzene ring lie in a propeller arrangement around the central tertiary amine N atom. The dihedral angles formed by the benzene ring with the pyridine rings are 61.0 (3) and 49.6 (3)°, while the dihedral angle between the pyridine rings is 69.7 (3)°. The mol-ecular conformation is stabilized by intramolecular bifurcated O-H⋯N hydrogen bonds. In the crystal, inversion dimers are formed via pairs of C-H⋯N hydrogen bonds.

DFT studies on some properties of maleonitriledithiolate complexes [M(mnt)2]2- (M=Ni, Pd, Pt and Zn, Cd, Hg).

The structures and some molecular properties of the complexes M(mnt)(2)(2-) (M=Ni, Pd, Pt and Zn, Cd, Hg; mnt(2-)=deprotonated maleonitriledithiolate) have been studied by using density functional theory (DFT) B3LYP/LanL2DZ level of theory. Computed binding energies show that the sequences of binding strengths are Ni

Application of ionic liquids containing tricyanomethanide [C(CN)3]- or tetracyanoborate [B(CN)4]- anions in dye-sensitized solar cells.

A series of novel ionic liquids composed of imidazolium, pyridinium, pyrrolidinium, and ammonium cations with tricyanomethanide or tetracyanoborate anions were prepared. The ionic liquids were characterized by NMR and IR spectroscopy and ESI-mass spectrometry, and their physical properties were investigated. Solid state structures of the N-propyl-N-methylpyrrolidinium and triethylpropylammonium tetracyanoborate salts were obtained by single crystal X-ray diffraction. The salts that are liquid at room temperature were evaluated as electrolyte additives in dye-sensitized solar cells, giving rise to efficiencies 7.35 and 7.85% under 100 and 10% Sun, respectively, in combination with the standard Z907 dye.

An internal fluorescent probe based on anthracene to evaluate cation-anion interactions in imidazolium salts.

A series of fluorescent imidazolium-based salts containing the cation [AnCH(2)MeIm](+) (in which An = anthracene and Im = the imidazolium cation) with Cl(-), BF(4)(-), PF(6)(-), SO(3)CF(3)(-), [N(CN)(2)](-), [N(SO(2)CF(3))(2)](-), or PhBF(3)(-) anions have been prepared and characterized. X-ray diffraction analysis of four of the salts reveals a number of C-H...X-type (X = O, N, F) hydrogen bonds between the hydrogen atoms from the imidazolium ring and in some cases from the anthracene ring with the electronegative atoms of the anions. Additionally, C-H...pi interactions can be found in all the salts analyzed by X-ray diffraction, whereas pi-pi stacking is observed only in the salt containing the phenyltrifluoroborate anion. Fluorescence emission analysis in acetonitrile shows that the fluorescence of these salts varies significantly according to the nature of the anion, and correlates to the extent of ion pairing present in solution. Photodimerization of these salts was observed, and in one case a dimer has been isolated and characterized by X-ray crystallography.

N,N'-Bis(2-quinolylcarbon-yl)hydrazine.

The title compound, C(20)H(14)N(4)O(2), crystallizes in the ortho-rhom-bic system with a crystallographic twofold axis through the N-N bond. The mol-ecule is non-planar and the dihedral angle between two amide groups is 74.9 (2)°. An intra-molecular N-H⋯N hydrogen bond is present. In the crystal, the mol-ecules are packed in chains running along the c axis through inter-molecular N-H⋯O hydrogen bonds. These chains are further stabilized by inter-molecular C-H⋯O hydrogen bonds and C-H⋯π inter-actions leading to the formation of a three-dimensional network.

3-Methyl-4-(3-methyl-phen-yl)-5-(2-pyridyl)-4H-1,2,4-triazole.

In the mol-ecule of the title compound, C(15)H(14)N(4), the triazole ring is oriented at dihedral angles of 30.8 (2) and 67.4 (2)° with respect to the pyridine and benzene rings, respectively. The crystal structure is stabilized by C-H⋯N hydrogen-bonding inter-actions, forming chains of mol-ecules along [01].