Heng-Qing Jia

Metal–organic frameworks based on the pyridine-2,3-dicarboxylate and a flexible bispyridyl ligand: syntheses, structures, and photoluminescence

Three new metal–organic coordination polymers, [Cu(2,3-pydc)(bpp)]·2.5H2O (1), [Zn(2,3-pydc)(bpp)]·2.5H2O (2) and [Cd(2,3-pydc)(bpp)(H2O)]·3H2O (3) (2,3-pydcH2 = pyridine-2,3-dicarboxylic acid, bpp = 1,3-bis(4-pyridyl)propane), have been synthesized at room temperature. All complexes have metal ions serving as 4-connected nodes but represent two quite different structural motifs. Complexes 1 and 2 are isomorphous, both of which feature 2D → 3D parallel interpenetration. Each two-dimensional (2D) layer with (4, 4) topology is interlocked by two nearest neighbours, one above and one below, thus leading to an unusual 3D motif. Complex 3 has a non-interpenetrating 3D CdSO4 framework with cavities occupied by uncoordinated water molecules. The compounds have been characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis and X-ray crystallography. The photoluminescent studies of 2 and 3 show that both complexes exhibit intense fluorescent emissions at room temperature.

A two-dimensional molybdenum (V) phosphate with covalently bonded transition metal coordination complexes: hydrothermal synthesis and structure characterization of Na2[{Mn(phen)2(H2O)}{Mn(phen)2}3{Mn Mo12vO24 (HPO4)6(PO4)2(OH)6}]·4H2O (phen=1, 10-phenanthroline)

An organic-inorganic hybrid molybdenum phosphate, Na-2[{Mn(phen)(2)(H2O)} {Mn(phen)(2)}(3){(MnMo12O24)-O-v (HPO4)(6)(PO4)(2) (OH)(6)}] . 4H(2)O (phen=1,10-phenanthroline), involving molybdenum present in V oxidation state and covalently bonded transition metal coordination complexes, has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Deep brown-red crystals are formed in the triclinic system, space group P (1) over bar, a=16.581(l)Angstrom, b=18.354(1)Angstrom, c=24.485(2)Angstrom, alpha=80.589(l)degrees, beta=71.279(1)degrees, gamma=67.084(1)degrees, V=6493.8(8)Angstrom(3), Z=2, lambda(MoKalpha)=0.71073Angstrom (R(F)=0.0686 for 29,053 reflections). Data were collected on a Bruker Smart Apex CCD diffractometer at 293 K in the range of 1.76 < theta < 28.06degrees using omega-2theta scans technique. The structure of the title compound may be considered to be based on {Mo6O12(HPO4)(3)(PO4)(OH)(3)} units bonded together with {Mn(phen)(2)} subunits into a two-dimensional network. Two types of tunnels are observed in the solid of the title compound.

Construction of coordination networks with high connectivity: a new 8-connected self-penetrating network based on tetranuclear metal clusters

Two highly connected cobalt(II) and zinc(II) coordination polymers with tetranuclear metal clusters as the nodes of network have been prepared, being the first example of an 8-connected self-penetrating net based on a cross-linked α-Po subnet.

Supramolecular isomerism in zinc hydroxide coordination polymers with pyridine-2,4-dicarboxylic acid: Two polymorphs with centrosymmetric two-dimensional and acentric three-dimensional coordination networks

Reactions of Zn(BF4)2 and pyridine-2,4-dicarboxylic acid (2,4-pydcH2) in the presence of 1,2-bis(4-pyridyl)ethylene or 1,3-bis(4-pyridyl)propane under hydro(solvo)thermal conditions yielded two polymorphic metal–organic coordination polymers formulated as Zn2(OH)2(2,4-pydc) (1 and 2). Polymorph 1 features a two-dimensional (2-D) layer-like structure that is constructed by 2,4-pydc ligands bridging between the Zn–OH–Zn double-chain units. Each single Zn–OH–Zn chain is composed of μ2-OH groups connecting trigonal bipyramidal and tetrahedral Zn centers. Polymorph 2 is a 3-D coordination polymer containing 2-D Zn–OH–Zn sheets that consist of μ2- and μ3-OH groups and trigonal bipyramidal Zn centers. The sheets are pillared by 2,4-pydc ligands to form an acentric structural architecture. 1 and 2 are rare examples that the two polymorphs exhibit a centrosymmetric 2-D coordination network and an acentric 3-D coordination network, respectively. The different structures lead to differences in photoluminescent properties and thermal stabilities for 1 and 2.

Novel two-dimensional sodium molybdenum phosphates containing {M(enMe)(2)}(2+) bridging groups (M = Ni, Cu; enMe=1,2-diaminopropane)

Two novel organic-inorganic hybrid compounds, (H(2)enMe)(4)(H3O)[Ni(enMe)(2)].[Na3Mo12O52P8(OH)(10)].5H(2)O (1) and (H(2)enMe)(4)(H3O)[Cu(enMe)(2)].[Na3Mo12O52P8(OH)(10)].5H(2)O (2) (enMe = 1,2-diaminopropane), have been hydrothermally synthesized and characterized by elemental analyses, IR, EPR, XPS, UV-Vis spectra and TG analyses. Single crystal X-ray diffraction shows that 1 and 2 are isostructural compounds. Both the compounds exhibit an unusual two-dimensional (2-D) window-like network consisting of one-dimensional (1-D) chains of sodium molybdenum phosphate anions connected by transition metal coordination complexes cations. Compound 1 and 2 represent the first 2-D molybdenum phosphate skeleton pillared by transition metal complex fragments.

Constructing porous frameworks from one-dimensional cobalt-oxygen clusters and pyridinedicarboxylate ligands adopting two rare coordination modes

A porous material with cobalt–oxygen cluster framework has been synthesized hydrothermally, which possesses large and rigid channels and manifests strong antiferromagnetic interactions, and the pyridinedicarboxylate ligand exhibits two types of rare coordination modes.

Hydrothermal synthesis and X-ray single crystal structure of bimetallic cluster complex [{Co(phen)2}2V4O12]·H2O

A new bimetallic cluster complex with the formula [{Co(phen)(2)}(2)V4O12](H2O)-H-. was synthesized from the hydrothermal reaction of V2O5, H2C2O4, Co(NO3)(2), 1,10-phenanthroline (phen), (C4H9)(4)NOH and water. The compound crystallizes in an orthorhombic system with space group Pbcn and unit cell parameters a = 19.106(3) Angstrom, b = 15.250(3) Angstrom, c = 16.321(2) Angstrom, V = 4755.4(13) Angstrom(3), Z = 4 and R = 0.0318. The bimetallic cluster complex [{Co(phen)(2)}(2)V4O12](H2O)-H-. is composed of a discrete V4O124- cluster eovalently attached to two [Co(phen)(2)](2+) fragments and the discrete hexanuclear bimetallic clusters of [{Co(phen)(2)}(V4O12)-V-2](H2O)-H-. are further extended into interesting three-dimensional supermolecular arrays via pi-pi stacking interactions of phen groups. Other characterizations by elemental analysis, IR, and thermal analysis are also described.

catena-Poly[diammonium [diaqua­bis(pyridine-2,4-dicarboxyl­ato-κ2N,O2)cuprate(II)] [[diaqua­copper(II)]-μ-pyridine-2,4-dicarboxyl­ato-κ3N,O2:O2′-[tetra­aqua­cadmium(II)]-μ-pyridine-2,4-dicarboxyl­ato-κ3O2:N,O2′] hexa­hydrate]

The title mixed-metal complex, {(NH4)2[Cu(C7H3NO4)2(H2O)2][CdCu(C7H3NO4)2(H2O)6]·6H2O}n, contains one octahedrally coordinated CdII center and two octahedrally coordinated CuII centers, each lying on an inversion center. The two CuII atoms are each coordinated by two O atoms and two N atoms from two 2,4-pydc (2,4-H2pydc = pyridine-2,4-dicarboxylic acid) ligands in the equatorial plane and two water molecules at the axial sites, thus producing two crystallographically independent [Cu(2,4-pydc)2(H2O)2]2− metalloligands. One metalloligand exists as a discrete anion and the other connects the Cd(H2O)4 units, forming a neutral chain. O—H⋯O and N—H⋯O hydrogen bonds connects the polymeric chains, complex anions, ammonium cations and uncoordinated water molecules into a three-dimensional supramolecular network.

Hydrothermal synthesis and crystal structure of a hybrid material based on [Co4(phen)8(H2O)2(HPO3)2]4+ and a highly reduced polyoxoanion

An unusual composite hybrid material [Co4(phen)8(H2O)2(HPO3)2](H3O)3[PMoVI8VIV4O40(VIVO)2] 1 (phen = 1,10-phenanthroline) has been hydrothermally synthesized from a mixture of NH4VO3, Na2MoO4·2H2O, CoCl2·6H2O, phen, H3PO3 and water. It was characterized by elemental analysis, IR, UV-vis, XPS, EPR, TG and single crystal X-ray diffraction. The title compound is constructed from the organic–inorganic hybrid [Co4(phen)8(H2O)2(HPO3)2]4+ and highly reduced bi-capped pseudo-Keggin [PMoVI8VIV4O40(VIVO)2]7− polyoxoanions The structure exhibits an extended 2D network through hydrogen bonds among cations, anions and H2O, combining polyoxometalates with metal phosphonates for the first time.

The synthesis and crystal structure of vanadium complexes: [VIVO2(phen)2]·6H2O and [2,2′-(bipy)2VVO2](H2BO3)·3H2O

Abstract The organic–inorganic hybrid materials vanadium oxide [VIVO2(phen)2]·6H2O (1) and [(2,2′-bipy)2VVO2](H2BO3)·3H2O (2) have been conventional and hydrothermal synthesized and characterized by single crystal X-ray diffraction, elemental analyses, respectively. Although the method and the ligand had been used in the syntheses of the compounds (1) and (2) are different, they almost possess similar structure. They all exhibit the distorted octahedral [VO2N4] unit with organonitrogen donors of the phen and 2,2′-bipy ligands, respectively, which coordinated directly to the vanadium oxide framework. And they are both non-mixed-valence complexes. But the compound (1) is isolated, and the compound (2) consists of a cation of [(2,2′-bipy)2VVO2]+ and an anion of (H2BO3)−. So the valence of vanadium of (1) and (2) are tetravalence and pentavalence, respectively. Meanwhile it is noteworthy that π–π stacking interaction between adjacent phen and 2,2′-bipy groups in compounds 1 and 2 also play a significant role in stabilization of the structure. Thus, the structure of [VIVO2(phen)2]·6H2O and [(2,2′-bipy)2VVO2](H2BO3)·3H2O are both further extended into interesting three-dimensional supramolecular. Crystal data: (1) Triclinic, P 1 , a=8.481(4), b=12.097(5), and c=14.607(6) A , α=66.32(2), β=82.97(3), and γ=82.59(4)°, V=1357.0(10) A 3 , Z=2, R1=0.0685, wR2=0.1522. (2) Triclinic, P 1 , a=6.643(13), b=11.794(2), and c=14.822(3) A , α=101.39(3), β=101.59(3), and γ=97.15(3)°, V=1098.8(4) A 3 , Z=2, R1=0.0736, wR2=0.1998.