Yong-Cai Qiu

In situ solvothermal syntheses of a heteronuclear copper(I)-alkaline metallic tetrazole-based coordination polymer

Three novel heteronuclear coordination complexes, namely, [Cu2K(Mtta)I2] (1), [Cu3K(Mtta)3I] (2) and [Cu2Na(Mtta)2(CH3CN)I] (3) (HMtta = 5-methyl-1H-tetrazole) have been solvothermal synthesized by CuI, MCl [M = K (1) and (2); M = Na (3)], sodium azide and acetonitrile generated via a [3 + 2] cycloaddition reaction of acetonitrile and sodium azide. Single crystal X-ray diffraction reveals that all complexes are three-dimensional (3D) frameworks, where complex 1 is constructed by connecting rare µ5-N bridging Mtta ligands to Cu–I–K layers, complex 2 is built up by connecting inorganic cationic [Cu6I2]4+ clusters with numerous Mtta ligands, while complex 3 is constructed from open Cu(Mtta) subnets and Na+ centers. Furthermore, the luminescence properties of all complexes have been investigated. This work further supplements the mechanism of the Demko-Sharpless reaction in heteronuclear tetrazole-based coordination polymers.

Self-assembly of d–f coordination frameworks based on 1H-benzimidazole-5-carboxylic acid: synthesis, structure and luminescence

By the addition of different secondary ligands [acetate (OAc), Br− and oxalate (ox)], or by the absence of such ligands, four different types of heterometallic coordination compounds were obtained by reaction of 1H-benzimidazole-5-carboxylic acid (H2bic) with transition metal (d) and lanthanide (f) ions under hydrothermal conditions, namely, [TbAg3(Hbic)2(bic)2]·4H2O (1), [LnCu2(Hbic)4Br] [Ln = Er (2), Ln = Yb (3)], [EuAg2(Hbic)2(bic)(OAc)(H2O)] (4), [TbAg(Hbic)3·(ox)0.5] (5). Compounds 1, 2 and 3 stand out by having octahedrally coordinated lanthanide centers rather than the more usual 8 or 9 coordinated metal centers. Complex 1 exhibits an interesting 2D wave-like layered network constructed from infinite six-coordinated terbium carboxylate chains and Ag3(Hbic)2(bic)2 units. Isostructural compounds 2 and 3 display two-dimensional (2D) mildly ruffled sheets constructed by interconnecting μ2-Br ligands to adjacent ribbon-shaped Cu2(Hbic)4 chains. Addition of auxiliary acetate and oxalate ions led to lanthanide ions with normal coordination numbers, and Eu2(OAc)2 and Tb(ox) subunits are formed. Complex 4 is a 2D structure with a (4,4) net that is constructed by interlinking dinuclear Eu2(OAc)2 subunits with Ag2(bic)(Hbic)2(H2O) subunits. Complex 5 represents a 2D heterometallic coordination framework with an (8,3) net that is constructed by interconnection of Ag(Hbic)3 subunits and Tb(ox) subunits. The luminescence properties of 1, 4 and 5 are discussed.

Diaqua­bis[5-(pyrazin-2-yl)tetra­zolato]iron(II)

The title complex, [Fe(C5H3N3)2(H2O)2], has a crystallographically imposed inversion centre. The FeII atom is coordinxadated by four N atoms from two 5-(pyrazin-2-yl)tetraxadzolate ligands and the O atoms from two water molxadecules in a distorted octaxadhedral geometry. The packing is governed by intraxadmolecular O—H⋯N hydrogen bonds.

Diaquabis[5-(pyrazin-2-yl)tetrazolato]cobalt(II)

In the title complex, [Co(C5H3N3)2(H2O)2], prepared in a one-pot synthesis, the CoII atom (site symmetry overline{1}), is coordinated by four N atoms from two 5-(2-pyrazinxadyl)tetraxadzolate ligands and by two water molxadecules in a distorted trans-CoO2N4 octaxadhedral geometry. A supraxadmolecular network is formed via interxadmolecular O—H⋯N hydrogen bonds.

Bis[aqua­chloro­bis(1,10-phenanthroline)cadmium(II)] benzene-1,4-dioxy­diacetate sesquihydrate

In the title compound, [CdCl(C12H8N2)2(H2O)]2(C10H8O6)·1.5H2O, the CdII atom is coordinated by four N atoms from two phenanthroline ligands, one Cl ligand and one water molxadecule, and displays a distorted octaxadhedral geometry. The anion is centrosymmetric. The packing is governed by interxadmolecular hydrogen bonds and a π–π stacking interxadaction.

2-Hydroxy-3-methoxybenzoic acid

The title compound, C8H8O4, has an intraxadmolecular O—H⋯O hydrogen bond. Interxadmolecular O—H⋯O hydrogen bonding gives rise to a dimeric structure, which is further extended into infinite stacks parallel to the a axis via π–π interxadactions between the aromatic rings of neigboring molxadecules.

Diaquabis(1,10-phenanthroline-κ2N,N′)nickel(II) diperchlorate 0.4-hydrate

The title complex, [Ni(C12H8N2)2(H2O)2](ClO4)2·0.4H2O, possesses crystallographically imposed C2 symmetry. The NiII atom is coordinated by four N atoms from two 1,10-phenanthroline ligands and two water molxadecules in a distorted octaxadhedral coordination geometry. The packing is governed by interxadmolecular hydrogen bonds and a π–π stacking interxadaction with a centroid-to-centroid distance of 3.650u2005(2)u2005A.

Bis(μ-3,5-dinitrosalicylato)hexaimidazoledicadmium(II) dihydrate

The title dinuclear complex, [Cd2(C7H3N2O7)2(C3H4N2)6]·2H2O, lies about an inversion centre. Each CdII atom is coordinated by three O atoms from two 3,5-dinitroxadsalicylate ligands and the N atoms of three imidazole ligands. Three ligand O atoms and one N atom lie in the equatorial plane with the two other imidazole ligands axial in a distorted octaxadhedral coordination environment. The intramolecular Cd⋯Cd separation is 3.906u2005(4)u2005A. In the crystal structure, a supraxadmolecular network forms through extensive interxadmolecular hydrogen-bonding interxadactions. One imidazole ring is disordered over two orientations in ratio of approximately 0.8:0.2.

Poly[[diaquatris[μ4-(p-phenylenedioxy)diacetato]dipraseodymium(III)] dihydrate]

The title praseodymium coordination polymer, {[Pr2(C10H8O6)3(H2O)2]·2H2O}n, was obtained by the hydroxadthermal reaction of Pr(NO3)3 with (p-phenylxadenedixadoxy)diacetic acid in alkaline aqueous solution. Each PrIII atom is coordinated by nine O atoms, eight from four (p-phenylxadenedixadoxy)diacetate ligands and one from a water molxadecule, displaying a tricapped trigonal prismatic geometry. There is a centre of symmetry at the mid-point of the Pr⋯Pr vector. The bridging ligands crosslink the metal ions to form a three-dimensional network, with channels running along the c axis in which the uncoordinated water molxadecules are located. The crystal structure is stabilized by interxadmolecular O—H⋯O hydrogen-bonding interxadactions.

(1R)-6,9,15,18,21-Penta­azapenta­cyclo­[12.7.0.01,18.02,7.08,13]henicosa-2,4,6,8(13),9,11,14-hepta­ene

The reaction of 1,10-phenanthroline-5,6-dione and diethylxadenetriamine unexpectedly yielded the title compound, C16H15N5, which is a non-planar and chiral fused-ring system composed of two pyridine rings and three non-aromatic rings. Crystal symmetry results in a racemic mixture of enantixadomers. Aromatic π–π stacking interxadactions exist between adjacent molxadecules and weak bifurcated N—H⋯(N,N) hydrogen bonds lead to dimeric associations of molxadecules, generated by inversion.