Peihai Wei

Exploratory syntheses, structures, and photoluminescent properties of three lead multi-dimensional frameworks

Three structurally diverse PbII coordination complexes, [Pb3O(OH)(4-sphth)]2(H2O) (1), [Pb(3,5-Hdhb)]H2O (2), and [Pb3(4-nphth)2(OH)2] (3) (4-H3sphth, 4-sulfophthalic acid; 3,5-H2dhb, 3,5-dihydroxybenzoic acid; 4-H2nphth, 4-nitrophthalic acid), were synthesized under hydrothermal conditions. X-ray diffraction analyses reveal that 1 is constructed from [Pb4O4] cubanes, based on which ladder-shaped structure is built via 4-H3sphth bridge. This is the first Pb4O4-containing polymer. The Pb2O2 units in 2 are bridged by two parallel 3,5-HDHB ligands along the a-axis and two other parallel 3,5-HDHB ligands along the b-axis, forming a 3-D framework. For 3, the crystal structure is built up of a layer motif consisting of corner-sharing pyramidal Pb3O units, which are linked through Pb corners to form a hexagonal unit. Each PbO6 polyhedron is connected to three polyhedra (Pb3O) via sharing an edge (two μ 3-oxygen atoms) and two faces (three μ 3-oxygen atoms), thus yielding an infinite 2-D Pb–O–Pb (3,6-net) honeycomb layer. The luminescence of 1–3 demonstrates that they may be good candidates for luminescent materials.

Syntheses and crystal structures of three coordination polymers based on terphenyl-2,5,2′,5′-tetracarboxylic acid

Solvothermal reactions of terphenyl-2,5,2′,5′-tetracarboxylic acid (H4qptc) and MII (M=Co, Ni, Cu) in the presence of 2,2′-bipyridine (2,2′-bpy) afford three new coordination polymers, [M(qptc)0.5(2,2′-bpy)(H2O)] n (M=Co (1), Ni (2)) and [Cu(H2qptc)(2,2′-bpy)] n (3). The structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR, and TGA. Complexes 1 and 2 are isostructural and display a 2-D layer wherein qptc4− is a twisted H-shaped ligand connecting CoII centers. Furthermore, 3-D structures in 1 and 2 are formed via inter-chain π···π interactions between neighboring 2,2′-bpy ligands, with the centroid–centroid distances of 3.619–3.822 Å. In 3, two deprotonated carboxyl groups of H2qptc2− are a Z-shaped ligand linking CuII centers to a 1-D zigzag polymeric chain. A 2-D layer structure is built with the help of inter-chain π···π interactions between the 2,2′-bpy and H2qptc2−.

Synthesis and crystal structures of three new complexes derived from 3-(pyridin-3′-yl)-5-(pyridin-2′′-yl)-1,2,4-triazole

Three new coordination complexes, [Cd2(ppt)2(cpba)] · (H2O)2 (1), [Zn(ppt)2] · (H2O) (2), and [Zn(MoO4)(Hppt)] (3) (H2cpba: 3-(2′-carboxy-phenoxy)-benzoic acid; Hppt: 3-(pyridin-3′-yl)-5-(pyridin-2′′-yl)-1,2,4-triazole), were synthesized under hydrothermal conditions. Their structures have been determined by single crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. X-ray diffraction analyses revealed that Cd(II) ions are linked by ppt− to form a ladder-shaped structure along the a-axis and further displays a 2-D supramolecular architecture with cpba2− along the c-axis. In 2, each Zn(ppt)2 fragment is linked by the nitrogen of pyridin-3′-yl from the neighboring Zn(ppt)2 forming a V-shaped chain. Compound 3 consists of a ladder structure, in which each {MoO4} unit is a bridge linking three Zn(Hppt)2+ fragments.

Exploratory syntheses, crystal structures, and properties of two new 3-D coordination polymers of Mn(II) and Fe(II) with (54.62) (510.63.7.8) topological spaces

Solvothermal reactions of terphenyl-2,5,2′,5′-tetracarboxylic acid (H4qptc) and MII (M = Mn, Fe) in the presence of 1,2-bis(diphenylphosphino)ethane (dppe) afford two new coordination polymers, [M(qptc)(dppe-O)] n (M = Mn (1), Fe (2)) (1,2-bis(diphenylphosphoryl)ethane = dppe-O). The structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR, TGA, and magnetism. The MII in 1 and 2 are linked by qptc4− to form 2-D layers, which are further connected via the oxidized dppe (dppe-O) exhibiting a (4,6)-connected network with the (54.62)(510.63.7.8) topology.

Exploratory syntheses and structural characterizations of three organic–inorganic hybrid polyoxomolybdate frameworks linked by M(II)-Ln units (M = Ni, Co, Zn; L = 2,2′-biimidazole)

Three new polyoxomolybdate compounds, {[Ni(H2biim)2(H2O)](Mo3O10)} n (1), [Co(H2biim)2(Hbiim)]2(H2Mo8O26)](H2O)4 (2), and {[Zn(H2biim)2(H2O)][Mo8O28(MoO2(H2biim)2)2](H4biim) (3) (H2biim, 2,2′-biimidazole), were designed and synthesized under hydrothermal conditions. X-ray diffraction analysis reveals that 1 is a snake-shaped chain consisting of asymmetric blocks of {Mo3O10}, in which the ratio of the octahedra {MoO6} and square pyramids {MoO5} is 1 : 2. Compounds 2 and 3 exhibit different structures, although similar synthetic environments (including pH, temperature, and reaction time) were employed. In 2, the cluster of H2Mo8 is decorated by two fragments of Co(H2biim)2(Hbiim)+ via the organic bridge of Hbiim−. Compound 3 consists of one γ-Mo8 , capped by two fragments of {MoO2(H2biim)2)2}2+ via terminal oxygens.

Bis{2-meth­oxy-6-[tris­(hydroxy­meth­yl)methyl­imino­meth­yl]phenolato-κ3O,N,O′}manganese(II) dimethanol solvate hemihydrate

In the title complex, [Mn(C12H16NO5)2]·2CH3OH·0.5H2O, the MnII atom has a distorted octahedral coordination geometry in which two N atoms from two 6-methoxy-2-[tris(hydroxymethyl)methyliminomethyl]phenolate ligands adopt a trans arrangement. The Mn—O(H) bonds (mean length 2.134 Å) are significantly longer than the Mn—O and Mn—N bonds (mean length 2.011 and 2.027 Å, respectively), and the dihedral angle between the mean planes through the aromatic rings of the two ligands is 76.8 (1)°. A complex network of O—H⋯O hydrogen bonds is formed between the complexes and the uncoordinated methanol and water molecules. The C and O atoms of one C—OH group are disordered with equal occupancies.

Tetra-μ-oxido-tetra­kis{dioxido[3-(2-pyrid­yl)-1H-pyrazole]molybdenum(VI)}

In the title compound, [Mo4O12(C8H7N3)4], the MoVI ion has a distorted octahedral coordination completed by two terminal O atoms, two μ-oxide atoms and two N atoms from one 3-(2-pyridyl)-1H-pyrazole ligand. It is noteworthy that in the tetranuclear unit ( symmetry), any three MoVI atoms define a plane, and the fourth lies 1.8 (1) Å out of that plane. The degree of linearity of the oxide bridges between two Mo atoms is 175.38 (13)°. Moreover, the N—H group forms an intramolecular hydrogen bond (four per molecule).

Bis{tris[3-(2-pyridyl)-1H-pyrazole]zinc(II)} dodecamolybdosilicate hexahydrate

The asymmetric unit of the title compound, [Zn(C8H7N3)3]2[SiMo12O40]·6H2O, consists of a complex [Zn(C8H7N3)3]2+ cation, half of a Keggin-type [SiMo12O40]4− heteropolyanion and three uncoordinated water molecules. The Zn2+ cation is surrounded in a distorted octahedral coordination by six N atoms from three chelating 3-(2-pyridyl)pyrazole ligands. In the heteropolyanion, two O atoms of the central SiO4 group ( symmetry) are equally disordered about an inversion centre. N—H⋯O hydrogen bonding between the cations, anions and the uncoordinated water molecules leads to a consolidation of the structure.

Syntheses and crystal structures of two new heteropolyoxometalates consisting of octamolybdate anions

Two new polyoxomolybdate compounds, [ZnII(Hppz)3]2(Mo8O26) (1) and [NiII(bpy2]2(Mo8O26) (2) (Hppz: 3-(2-pyridyl)pyrazole); bpy: 2,2′-bipyridine), were synthesized under hydrothermal conditions. X-ray diffraction analyses reveal that 1 consists of one β-octamolybdate and one ZnII . Compound 2 consists of one α-octamolybdate linked by two Ni complexes via terminal oxygen bridges. Crystal data of 1: C24H21Mo4N9O13Zn, M = 1092.63, monoclinic, P21/n, a = 12.4456(18), b = 16.231(2), c = 17.710(3) Å, β = 109.883(2)°, V = 3364.4(9) Å3, Z = 4, D calcd = 2.157 g cm−3, F(000) = 2120, μ = 2.229 mm−1, R 1 = 0.0394 and wR 2 = 0.1139 (I > 2σ(I)); Crystal data of 2: C40H32Mo8N8Ni2O26, M = 1925.68, triclinic, P-1, a = 10.1608(5), b = 11.6091(6), c = 13.8789(7) Å, α = 114.2120(10)°, β = 95.8650(10)°, γ = 102.7460(10)°, V = 1421.75(12) Å3, Z = 1, D calcd = 2.249 g cm−3, F(000) = 928, μ = 2.435 mm−1, R 1 = 0.0220 and wR 2 = 0.0741 (I > 2σ(I)).

Bis{tris-[3-(2-pyrid-yl)-1H-pyrazole]nickel(II)} dodeca-molybdosilicate tetra-hydrate.

The asymmetric unit of the title compound, [Ni(C8H7N3)3]2[SiMo12O40]·4H2O, consists of a complex [Ni(C8H7N3)3]2+ cation, half of a Keggin-type heteropolyanion [SiMo12O40]4− and two uncoordinated water molecules. The Ni2+ cation is surrounded in a slightly distorted octahedral coordination by six N atoms from three chelating 3-(2-pyridyl)-1H-pyrazole ligands. In the heteropolyanion, two O atoms of the central SiO4 group ( symmetry) are equally disordered about an inversion centre. N—H⋯O and O—H⋯O hydrogen bonding between the cations, anions and the uncoordinated water molecules leads to a consolidation of the structure.