Turan K. Yazicilar

SYNTHESIS, CHARACTERIZATION, AND SPECTRAL AND THERMAL STUDIES OF SOME DIVALENT TRANSITION METAL COMPLEXES OF BENZYLPIPERAZINE DITHIOCARBAMATE

Potassium benzylpiperazine dithiocarbamate (KBPDTC) and its complexes with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized and characterized. On the basis of elemental analyses, magnetic moments and spectral data, the monoanionic BPDTC ligand coordinates to the metal ions via both sulfur atoms of the -NCS2 group, acting as a bidentate ligand. The Ni(II) complex has a square-planar coordination geometry, while the other complexes are suggested to exhibit a square-pyramidal coordination environment. The thermal reactivity of KBPDTC.H2O and its metal complexes has been studied by means of DTA and TG techniques. Thermoanalytical data show that decomposition of the metal complexes of KBPDTC under nitrogen gives the corresponding metal thiocyanates as stable solid intermediates.

Syntheses, crystallographic, mass-spectroscopic determination and antioxidant studies of Co(II), Ni(II) and Cu(II) complexes of a new imidazol based Schiff base

A new imidazole-based Schiff base, 2-((1H-imidazol-4-yl)methyleneamino)benzylalcohol (HL) and corresponding analogous bis(2-((1H-imidazol-4-yl)methyleneimino)benzylalcohol)metal(II) perchlorates (M: Co(1), Ni(2), Cu(3)) have prepared and characterized by elemental analyses, ESI-MS, IR, UV-Vis spectroscopies and conductivity measurements. X-ray single crystal structures of 1 and 2 have been also determined. Elemental analyses, spectroscopic and conductance data of 3 demonstrated similar structural features with these of crystallographically characterized complexes and based upon this relevances, HL ligands are neutrally coordinated to metal(II) ions in tridentate mode and all complexes are isostructural, dicathionic, contain perchlorate anions as complementary ions and, are in octahedral geometry with the formulae of [M(HL)2](ClO4)2 (for 3) and [M(HL)2](ClO4)2·H2O (for 1 and 2). Radical scavenging activities of the complexes have been evaluated by using DPPH, DMPD(+), and ABTS(+) assays. SC50 values (μg/mL) of the complexes and standards on DPPH, DMPD(+), ABTS(+) follow the sequences, BHA (9.06±0.33)>CMPD3 (15.62±0.52)>CMPD2 (17.43±0.29)>Rutin (21.65±0.60)>CMPD1 (25.67±0.51)>Trolox (28.57±0.37), Rutin>BHA>CMPD3>CMPD2>Trolox>CMPD1, and Trolox>BHA>CMPD3>CMPD2>Rutin>CMPD1 respectively.

Metal Complexes of Phenylpiperazine‐Based Dithiocarbamate Ligands. Synthesis, Characterization, Spectroscopic, Thermal, and Antimicrobial Activity Studies

Potassium salts of phenylpiperazine (Phpzdtc), fluorophenylpiperazine (F‐Phpzdtc) and nitrophenylpiperazine (N‐Phpzdtc) dithiocarbamates and their manganese(II), iron(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes have been synthesized and characterized by elemental analyses, IR, UV‐VIS, magnetic moment measurements and thermal analysis techniques. On the basis of experimental data, the dithiocarbamates (dtcs) have been observed to coordinate to the metal ions via both sulphur atoms of the –NCS2 group forming metal complexes with a metal to ligand ratio of 1:2. The thermal reactivity and antimicrobial activity of the ligands and their metal complexes were also studied. The decomposition of the metal complexes resulted in the formation of the corresponding metal thiocyanates or cyanates as stable intermediates. Phpzdtc was found to be microbiologically more active than its nitro and fluoro derivatives and biological activity of the dtc ligands either remained unaltered or decreased on complexation with metal ions.

Bis(p-nitrobenzoxasulfamato) Complexes of Cadmium(II) and Mercury(II) Synthesis, Spectra, and X-Ray Crystal Structures

The reaction of sodium benzoxasulfamate (nbs) with cad- mium(II) and mercury(II) sulfate in aqueous solution yield the no- vel complexes (Cd(nbs)2(H2O)4) (1) and (Hg(nbs)2(H2O)3 )( 2), respectively. The complexes were characterized by elemental analy- ses, IR spectroscopy and X-ray crystallography. Complex 1 is monomeric and has an octahedral arrangement in which the N-donor nbs ligands occupy the axial positions, while the water oxygen atoms form the equatorial plane. Complex 2 is polymeric and shows a pentagonal bipyramidal arrangement achieved by the bridging of the HgN2O3 units through the weak interaction of the

Sodium p-nitro­benzoxasulfamate monohydrate

The title compound, alternatively named sodium 6-nitro-3H-1,2,3-benzoxathiazole 2,2-dioxide monohydrate, Na+*C6H3N2O5S-*H2O, consists of chains of NaO7 units, with the seven donor-O atoms coming from two water molecules and five p-nitrobenzoxasulfamate anions. The seven-coordinate geometry around the Na+ ion is described as monocapped trigonal prismatic, but with a large distortion from ideal geometry. Each triangular face is defined by one O atom each from a water molecule, a nitro group and a sulfonyl group. An O atom from a sulfonyl group caps one of the square faces of the trigonal prism in an unsymmetrical fashion. The water molecules and one sulfonyl O atom are involved in bridging adjacent units, as is the nitro group of the anion. The sulfamate ions adopt an antiparallel alignment between the NaO7 units and are connected to each other by C-H...O and pi-pi interactions. The three-dimensional crystal structure is stabilized by a network of strong O-H...N hydrogen bonds.

Synthesis and Characterization of p-Dimethylaminobenzaldehyde Complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II)

Abstract The complexes of p-dimethylaminobenzaldehyde with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) have been prepared and characterized by elemental analysis, magnetic susceptibility, spectral and thermal analysis techniques. It is concluded that the ligand is coordinated to the metal ions as a monodentate ligand through the oxygen of the carbonyl group. The chloride ion and, in some cases, water molecules are coordinated to the metal ions to complete the geometry around the metal ions. Referee I: P. R. Singh Referee II: D. A. Knight

Electronic structure modeling of dinuclear copper(II)-methacrylic acid complex by density functional theory

A dinuclear centrosymmetric copper(II) complex with the formula [Cu2(μ-maa)4(maaH)2] has been synthesized and experimentally characterized by IR, electronic spectroscopy, and X-ray single-crystal diffractometry. Starting from experimental X-ray geometry and using antiferromagnetic singlet ground state, gas phase geometry optimization was performed by density functional hybrid (B3LYP) method with 6-31G(d) and LANL2DZ basis sets. Gas-phase vibrational frequencies and single point energy (SPE) calculations have been carried out at the geometry-optimized structure. Molecular electrostatic potential calculated at the optimized geometry and natural bond orbital analysis data have been extracted from SPE output. The gas-phase electronic transitions of the title complex were investigated by the time dependent-density functional theory (TD-DFT) approach with the same theory employing LANL2DZ basis set. Also the calculated UV-Vis based upon TD-DFT results and IR spectra were simulated for comparison with the experimental ones.

Synthesis, characterization and spectroscopic studies of 2,2'-bipyridyl complexes of metal benzenesulfonates

Abstract The new transition metal benzenesulfonate (bs) complexes of 2,2″-bipyridyl (bpy) have been synthesized and characterized by elemental analyses, magnetic moments, UV-Vis, IR, thermal analysis techniques. The bs anion does not coordinate to the metal ions and is present as the counter-ion in the Co(II) (2), Ni(II) (3) and Cu(II) (4) complexes, but coordinates to the Mn(II) ion as a monodentate ligand. The Mn(II) complex (1) crystallizes in the orthorhombic crystal system with Pbca space group. The complex (1) is the first crystallographically characterized Mn(II) benzenesulfanato complex in which the bs anion is coordinated to metal ion. The manganese centre has a significantly distorted octahedral coordination by two bpy and bs ligands. bs molecules are joined by O7—H7A...O2 and O7—H7B...O3 hydrogen bonds, forming a centrosymmetric dimers which are linked by π–π interactions. All complexes exhibit similar decomposition characteristics. Magnetic susceptibility measurement shows that complex 2 has orbital interaction.

2,2'-Bipyridin-1-ium 3-nitro-benzene-sulfonate.

In the title compound, C10H9N2 +·C6H4NO5S−, the dihedral angle between the aromatic rings of the cation is 9.42 (7)°. In the crystal, the anions and cations are linked by C—H⋯O and N—H⋯O hydrogen bonds, generating R 2 1(5) and R 4 4(14) rings, respectively. These hydrogen bonds also provide packing along [110].

Diaqua-bis(ethyl-enediamine-κN,N')copper(II) 2,2'-dithio-dinicotinate sesquihydrate.

In the title compound, [Cu(C2H8N2)2](C12H6N2O4S2)·1.5H2O, there are two half-molecules of the cationic complex in the asymmetric unit. The Cu2+ ions lie on inversion centres and are octahedrally coordinated by two ethylenediamine (en) and two aqua ligands in a typical Jahn–Teller distorted environment with the water O atoms in the axial positions. Two 2-mercaptonicotinate units (mnic) are linked by a disulfide bridge. All the ethylenediamine N—H and O—H groups form intermolecular hydrogen bonds with acceptor O and N atoms, giving rise to a three-dimensional network. One of the uncoordinated water molecules has a site occupation factor of 0.5.