Hydrothermal Synthesis and Crystal Structure of a Keggin Polyoxometalate [Co^Ⅱ（2,2′-bipy）2（H2O）]2[SiW^Ⅵ12O40]·2H2O

A Keggin-type tungstosilicate compound [Co^Ⅱ（2,2′-bipy）2（H2O）]2[SiW^Ⅵ12O40]·2H2O 1 （bipy = bipyridine） was prepared by a hydrothermal method for the first time. Single-crystal X-ray diffraction revealed that 1 （C40H40Co2N8O44SiW12） crystallizes in the triclinic system, space group P1 with a = 10.4979（6）, b = 13.3946（7）, c = 13.5756（8）A, α= 70.0769（18）, β = 68.910（3）, γ = 74.186（4）°, V = 1649.84（16）A^3, Mr = 3688.95, Z = 1, Dc = 3.713 mg·m^-3, μ = 21.432 mm^-1, F（000） = 1644, S = 1.058, the final R = 0.0511 and wR =0.1023 for 6523 observed reflections （I 〉 2σ（I））. Compound 1 consists of two coordinated cation fragments [Co^Ⅱ（2,2′-bipy）2（H2O）]^2＋, one normal Keggin polyanion unit [SiW^Ⅵ12O40]^4- and two lattice water molecules. To be noted, each polyanion unit is linked to two cation fragments by its two surface terminal oxygen atoms and two cobalt atoms of two cation fragments forming an organic-inorganic hybrid unit in 1. Furthermore, the compound shows strong photoluminescence property in the solid state at room temperature.     

Synthesis and Crystal Structure of 2,6-Bis（benzimidazo（1,2-c）- quinazolin-6-yl）pyridine Tetrahydrate

The title compound, 2,6-bis（benzimidazo（1,2-c）quinazolin-6-yl）pyridine tetrahydrate, was synthesized by simple condensation of 2-（2-sminophenyl） benzimidazole with pyfidine- 2,6-dicarboxylic acid and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group C2/c with a = 22.226（8）, b = 16.730（7）, c = 16.820（5）A, β = 115.796（13）°, V = 5631（4）A^3, C33H27NTO4, Mr = 585.62, Z = 8, Dc = 1.381 g/cm^3, λ（MoKα） = 0.71073 A, F（000） = 2448 and μ = 0.09 mm^-1. The structure was refined to the final R = 0.0730 and wR = 0.1573 for 6346 independent reflections （Rint = 0.0801） and 3384 observed reflections （I 〉 2σ（I））. In the crystal, the molecules are linked through intermolecular O-H…O and O-H…N hydrogen bonds. Intermolecular π-π interactions （with distances of about 3.45 A） are pronounced in the crystal structure.     

Synthesis and Crystal Structure of N,N′,N″- Tris-（2-aminophenyltriphenylphosphium）- benzene- 1,3,5-tricarboxamide

A new tripodal P,N ligand （C63H48N3O3P3） was prepared and characterized by elemental analysis, IR and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 13.013（3）, b = 28.406（6）, c = 14.911（3） A^°, β= 111.04（3）°, V= 5144.6（18） A^°^3 Z = 4, Dc = 1.276 g/cm^3, Mr = 987.95, λ（MoKa） = 0.71073 A^°,μ = 0.17 mm^-1, F（000） = 2064, R = 0.0786 and wR = 0.1545. A total of 43260 unique reflections were collected, of which 5112 with I 〉 2σ（I） were observed. The title compound has a central benzene ring, which is linked by -NH-CO- bonds to three 2-aminophenyltriphenylphosphium moieties, of which two with P（1） and P（2） centers are pointing to the same face of the central aryl ring, while the third one directs oppositely, forming a pseudo-propeller. In the crystal structure, there exist face-to-face π-π stacking interactions which increase the stability of the crystal structure.