Quan-Zheng Zhang

Syntheses, crystal structures, and properties of complexes constructed with polybenzoate and 2,2′-bibenzimidazole

Six new complexes constructed with polybenzoate and 2,2′-bibenzimidazole, namely, [Co(H2bibzim)(1,4-bdc)] (1), [Ni(H2bibzim)(1,4-bdc)] (2), [Co(H2bibzim)2(1,3-bdc)]·H2O (3), [Co4(H2bibzim)3(Hbibzim)2(1,3,5-btc)2·2H2O]·5H2O (4), [Co2(H2bibzim)4(1,2,4,5-btec)] (5), and [Ni(H2bibzim)3](1,4-bdc)·3H2O (6) (bdc = benzenedicarboxylate, H2bibzim = 2,2′-bibenzimidazole, btc = benzenetricarboxylate, btec = benzenetetracarboxylate) have been synthesized by hydrothermal methods and characterized by single crystal X-ray diffraction. Complexes 1 and 2 are isomorphous. Both crystallize in the monoclinic space group P21/c and feature 1-D “zigzag” chains, which can be further arranged into undulating sheets in a zipper-like fashion through π-π and hydrogen bonding interactions. Complex 3 belongs to the P21/c space group. Each Co(II) atom coordinates to one 1,3-bdc and two H2bibzim ligands. With the help of strong N–H⋯O hydrogen bonding interactions between H2bibzim and neighboring 1,3-bdc, a 2-D network with windows of about 14.8 × 18.2 A can be formed with [Co(H2bibzim)2(1,3-bdc)] dimers as building blocks. Complex 4 belongs to the Cc space group and features a 3-D framework. Interestingly, two of the five H2bibzim are deprotonated into Hbibzim− and act as bridging ligands. Complex 5 crystallizes in P-1, the dinuclear units are connected into a 2-D sheet through π–π and hydrogen bonding interactions, forming a molecular zipper synchronously. Complex 6 crystallizes in P21/n, the nickel atom is six coordinated by three H2bibzim ligands, and the terephthalate (tp) groups act as counterions, connecting the coordination cations into a 3-D framework through N–H⋯O hydrogen bonding interactions. The thermal stabilities of complexes 1–6 were examined. The temperature-dependent magnetic susceptibilities of complexes 1, 2 and 4 were also studied.

catena-Poly­[[[μ-pyridinium-3-carboxylato-bis[di­oxomolybdenum(VI)]]-di-μ3-oxo] monohydrate]

A novel chain molybdenum compound, [[Mo2O6(C6H5NO2)].H2O]n, which was synthesized under hydrothermal conditions, consists of an infinite rail-like chain formed by molybdenum oxide units linked by zwitterionic nicotinic acid ligands. Each Mo atom is coordinated octahedrally by six O atoms and the MoO6 octahedra are linked to one another via edge-sharing to produce a zigzag polymeric chain, with nicotinic acid ligands located, alternately, on each side of the rail-like chain plane.

Synthesis, Structural Characterization, and Magnetic Properties of a New Charge-Transfer Salt Composed of Polyoxotungstate Acceptors [WVWVI5O19]3− and Cationic Ferrocenyl CpFe+Cp Donors

The crystal structure of the charge-transfer slat (CpFe+Cp)3[WVWVI5O19] (CpFeCp=Fe(C5H5)2), synthesized from the reaction of Na2WO4⋅2H2O with ferrocene under acid conditions, has been determined by single-crystal X-ray diffraction. The crystal is of triclinic space group P(−1) with a=13.0374(3), b=15.0406(3), c=16.8239(1) Å, α=91.417(1), β=98.931(1), γ=115.294(1)°, V=2931.20(9) Å3, Z=1, Mr=5895.57, F(000)=2652, μ=18.735 mm−1, and Dc=3.340 g⋅cm−3. The final R factor is 0.0502 for 10173 (Rint=0.0563) unique reflections and 770 parameters. The structural analysis reveals that there are two crystallographically distinct [WVWVI5O19]3− polyoxoanions and six independent ferrocene cations per unit cell. Each polyoxoanion consists of six WO6 octahedra with three types of W–O bond lengths. Interestingly, CpFe+Cp moieties are stacked to form octagonal channels that incorporate the polyanions. The closest Fe⋅⋅⋅Fe distances between the neighboring ferrocenyl cations are more than 6.49 Å, therefore, a good magnetic isolation between the iron centers is expected.

Two new dinuclear complexes with flexible bipyrazole ligand bridged via μ-Cl or μ1,1-N3

Two dinuclear complexes, {[Cd(bdpp)Cl2](CH3OH)}2 (1) and [Cd(bdpp)(N3)(NO3)]2 (2), have been synthesized by reactions of bdpp with cadmium salts (bdpp = 1,3-bis(3′,5′-dimethylpyrazol-1′-yl)propane), and characterized by IR, element analysis, fluorescence properties and single crystal structural analysis. Cd in 1 has a trigonal bipyramidal coordination geometry and two such units form a dimer through two μ-Cl bridges. Each Cd in 2 has a distorted octahedral coordination geometry and two Cd units form a dimer through μ1,1-N3 bridges. The emission spectra show λem = 413 nm for 1 and λem = 338 nm for 2.

Poly[aqua­bis(μ4-benzene-1,2-dicarboxyl­ato)(μ3-benzene-1,2-dicarboxyl­ato)digadolinium(III)]

The title compound, [Gd2(C8H4O4)3(H2O)]n, is a two-dimensional coordination polymer. The Gd atoms are eight- and nine-coordinated. This compound is isostructural with its dysprosium analog.

Synthesis and crystal structure of a Cu(II) complex with mixed malonate/1,10-phenanthroline ligands

A Cu(II) complex with mixed ligands, [Cu3(mal)3(phen)3(H2O)2] · 11H2O (mal = malonate, phen = 1,10-phenanthroline) was synthesized and characterized by elemental analysis, IR, UV, electron paramagnetic resonance (EPR) and luminescence spectra and single-crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group Cc with a = 13.1631(10) Å, b = 20.1089(10) Å, c = 20.1267(13) Å, β = 103.500(3)°, V = 5180.2(6) Å3, Z = 4, and R 1 = 0.0476 for 7993 observed reflections. In the complex, one Cu is coordinated by a mal dianion and a phen molecule, exhibiting N2O2 square-planar geometry, while the other two Cu atoms are coordinated, respectively, by a mal dianion, a phen and water molecules, exhibiting N2O3 square pyramidal coordination geometry.

Synthesis and Structure of Two Keggin-Type Heteropolyanions: [VMo12O40]3n−n (1) and [H3PMoVMoVI11O40]1− (2)

Two Keggin-type heteropolyanions were synthesized and characterized by X-ray crystal structure and elemental analysis as well as infrared spectroscopy. Both K3[VMo12O40]⋅19H2O (1) and [Ni(H2O)6][H3PMoVMoVI11O40]2⋅30 H2O (2) were prepared in aqueous solution. Compound 1 crystallized in the space group Pm-3m, a=10.6513(1) Å, V=1208.4(3) Å3, Z=1. Compound 2 crystallized in the space group R-3 with a=b=13.9669(2) Å, c=42.0075(5) Å, V=7096.71(2) Å3, Z=3. The compound 1 contains a {K6VMo12O40} group in which six potassium ions form a regular {K6} octahedron. The heteropolyanion [VMo12O40]3− was capped by six potassium ions and enclosed by {K6} octahedron. A three-dimensional structure was formed by the buildup of {K3[VMo12O40]}n. Compound 2 contains a one-electron reduced heteropolyanion [H3PMoVMoVI11O40]1−. Ni2+ coordinated by six water molecules as the counter cation balances the negative charge of the molecule.

Bis[2-(3-pyridinio)benzimidazolium] di-μ-chloro-bis­[trichloro­cadmium(II)]

The title compound, (C12H11N3)2[Cd2Cl8], consists of two discrete 2-(3-pyridinio)benzimidazolium cations and one [Cd2Cl8]4- anion. The dimeric [Cd2Cl8]4- anion lies about an inversion centre and consists of two distorted [CdCl5] trigonal bipyramids which share a common edge. The two Cd atoms are each coordinated by two mu-Cl atoms and three terminal Cl atoms, with a Cd...Cd separation of 3.9853 (6) A. The packing displays two-dimensional hydrogen-bonded sheets, which are further linked by C-H...Cl contacts and pi-pi stacking interactions to yield a three-dimensional network.

Synthesis and structures of two cobalt complexes [NaCoII(NTA)(H2O)] n and NH4[CoIII(IDA)2] · 2H2O

Two cobalt complexes [NaCoII(nta)(H2O)] n (H3nta = nitrilotriacetic acid) (1) and NH4[CoIII(ida)2] · 2H2O (H2ida = iminodiacetic acid) (2) have been synthesized and characterized by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in the orthorhombic system, space group P212121 with a = 7.9770(12) Å, b = 9.7613(15) Å, c = 12.1945(18) Å, V = 949.5(2) Å3, Z = 4, and R 1 = 0.0705 for 1597 observed reflections. Compound 2 crystallizes in the monoclinic system, space group P2(1)/c with a = 5.1801(3) Å, b = 11.2073(6) Å, c = 12.2891(7) Å, V = 707.09(7) Å3, Z = 2, and R 1 = 0.0349 for 1143 observed reflections. In compound 1, the Co is coordinated by a nitrogen and five oxygen atoms in a distorted octahedral geometry {CoNO5}, and the Na is coordinated by one water molecule and four carboxyl oxygen atoms in slightly distorted square pyramidal geometry. The entire structure shows a three-dimensional network. In compound 2, Co atom is equatorially coordinated by two ida ligands in a distorted octahedral geometry {CoN2O4}. The discrete [Co(ida)2]2− anions are linked by hydrogen bonding to a three-dimensional supramolecular network.

A novel zigzag chain based on polyoxomolybdate decorated by glycine ligand in covalent bond

An unusual compound, K2[Mo4O13(NH3CH2COO)2] · 2H2O (1), has been synthesized and structurally characterized by the XRD, elemental analysis, IR spectrum, TG analyses and the single crystal X-ray diffraction. The structure of 1 exhibits a zigzag chain based on corner-shared tetramolybdate chelated by two bidentate glycine ligands.