Sabri Cevik

Hydrothermal Synthesis and Crystal Structure of Novel Oxovanadium Coordination Polymer: [(VIVO)2(OH)2(C10H6(COO)2)]∞

A novel coordination polymer [(VIVO)2(OH)2(C10H6(COO)2)]∞ based on vanadium(IV) and 2,6-naphthalenedicarboxylato ligand has been prepared by hydrothermal synthetic method. The compound was characterized by elemental analysis, thermogravimetric analysis, Fourier Transform infrared spectroscopy, room-temperature magnetic susceptibility measurement, manganometric titration, bond valance sum calculations (BVS), and single-crystal X-ray diffraction method. BVS calculations, manganometric titration, and room-temperature magnetic susceptibility measurement showed that the compound has paramagnetic property due to tetravalent vanadium ions. The single-crystal structure analysis of the compound illustrates a 2D metal organic framework structure. Coordination geometry of vanadium ions was a distorted square-pyramid (square-pyramidal coordination environment of oxygen atoms). The compound represents a novel 2D inorganic-organic coordination polymer involving vanadium(IV) and 2,6-naphthalenedicarboxylato ligand.

A Tridentate In Situ Generated Ligand Leading the Self-Assembly of a Transition Metal Coordination Polymer: Solvothermal Synthesis and Structural Characterization of 1D Cadmium Pyridine-2-Carboxylate

This work involves the synthesis and characterization of a transition metal based one-dimensional coordination polymer, [Cd2(2-pc)4]n, (2-pc = pyridine-2-carboxylate), which is the first example of a Cd-pyridin-2-carboxylate solid state structure with no other ligands. 2-pc ligand was not originally included in the reaction mixture. This ligand formed in situ from the mixture of cadmium acetate, 2,4,6-Tris(2-pyridyl)-s-triazine and ethyl alcohol under solvothermal reaction conditions. The coordination polymer was characterized by elemental analysis, IR spectroscopy, thermogravimetry and single crystal X-ray diffraction. The coordination compound crystallizes in the orthorhombic space group Pna21 with unit cell dimensions a = 8.2570(7) Å, b = 19.4647(14) Å, and c = 7.6715(6) Å. The structure of the compound consist of edge sharing distorted octahedrons (CdN2O4) and each cadmium atom is N/O chelated by two 2-pc ligands where the oxygen atoms act as bridging toward the adjacent cadmium ions.

Synthesis, structural, spectral, thermal and comparative biological activity studies of [V2O2(SO4)2(H2O)6]

The hydrothermal reaction of a mixture of V2O5, VCl3, 2,5-pyridinedicarboxylic acid and diluted H2SO4 for 68 h at 180°C gives a blue colored solution which yields prismatic blue crystals of IV2IVO2(SO4)2(H2O)6] (1) in 32% yield (based on V). Complex 1 was investigated by means of elemental analysis (C, H and S), TGA, FT-IR, manganometric titration, Single Crystal X-ray Diffraction Methods and also comparative antimicrobial activities. Crystal data for the compound: monoclinic space group P21/c and unit cell parameters are a = 7.3850(12) Å, b = 7.3990(7) Å, c = 12.229(2) Å, β = 108.976(12)° and Z = 2. Although structure of 1 as a natural mineral has been previously determined, this work covers new preparation method and full characterization of 1 along with comparison of antibacterial activity between 1 and the commercial vanadium(IV) oxide sulfate hydrate compounds, VOSO4 · xH2O (Riedel-de Haën and Alfa Aesar brand names). 1 was evaluated for the antimicrobial activity against gram-positive, gram-negative bacteria, yeasts and mould compared with the commercial VOSO4 · xH2O compounds. 1 showed weak activity against bacteria Bacillus cereus, Nocardia asteroides and yeast Candida albicans. A good antimicrobial activity was recorded against Cirtobacter freundii (15 mm). There are only a few reproducible well-defined vanadium(IV) starting materials to use for exploring the synthesis of new materials. VCl4, VO(acac)2, VOSO4 · xH2O and [V(IV)OSO4(H2O)4] · SO4 · [H2N(C2H4)2NH2] are common starting materials for such applications. In addition to these compounds, 1 can be used as an oxovanadium precursor.

Crystal structure of 4,4′-bipyridine-1,1’-diium naphthalene-2,6-di­sulfonate dihydrate

The title hydrated molecular organic salt, C10H10N2 2+·C10H6O6S2 2−·2H2O, crystallized with half a bipyridinium cation, half a naphthalene-2,6-disulfonate anion and a water molecule in the asymmetric unit. The whole cation and anion are generated by inversion symmetry, the inversion centers being at the center of the bridging C—C bond of the cation, and at the center of the fused C—C bond of the naphthalene group of the anion. In the crystal, the anions and cations stack alternately along the a axis with π–π interactions [inter-centroid distance = 3.491 (1) Å]. The anions are linked via O—H⋯O(sulfonate) hydrogen bonds involving two inversion-related water molecules, forming chains along [10-1]. These chains are bridged by bifurcated N—H⋯(O,O) hydrogen bonds, forming a three-dimensional framework structure. There are also C—H⋯O hydrogen bonds present, reinforcing the framework structure.

Poly[(μ5-2,2′-bipyridine-5,5′-dicarboxyl­ato)lead(II)]

In the title polymeric compound, [Pb(C12H6N2O4)]n, the PbII cation, located on a mirror plane, is N,N′-chelated by a 2-2′-bipyridine-5,5′-dicarboxylate (bpdc) anion and is further coordinated by six O atoms from four carboxyl groups of bpdc anions in an irregular N2O6 geometry. The carboxylate groups bridge the PbII cations, forming a three-dimensional polymeric structure. The carboxylate group is twisted away from the attached pyridine ring by 11.4 (3)°.

Redetermination of the mixed-valence hexa­nuclear manganese oxide complex di-μ4-oxo-tetra-μ3-pivalato-hexa-μ2-pivalato-tetra­kis(pivalic acid)dimanganese(III)tetra­manganese(II) at 100 K

The structure of the title compound, [Mn6(C4H9O2)10O2(C4H10O2)4], has been redetermined at 100 K. The improved precision of the structure determination allowed the determination of the positions of the MnIII atoms in the Mn6O2 core. The MnIII⋯MnIII distance of 2.744 (3) A is significantly shorter than the remaining MnII⋯MnIII distances [3.106 (3)–3.137 (3) A].