Hümeyra Paşaoğlu

Synthesis, IR spectrum, thermal behaviour and crystal structure of a novel one-dimensional cyano-bridged zinc(II)/nickel(II) complex

Abstract The cyano-bridged heteronuclear coordination polymer of zinc(II)/nickel(II) has been prepared by N-(2-hydroxyethyl)-ethylendiamine (hydet-en), alternatively named 2-(2-aminoethylamino)-ethanol and characterised by IR and thermal analysis. In the bimetallic complex, the decomposition of hydet-en ligands is seen to be endothermic whereas that of the cyano ligands is found to be exothermic. The crystal structure of the complex has been determined by single-crystal X-ray diffraction. The crystal structure of the zinc(II)-nickel(II) complex consists of a one-dimensional polymeric chain –Zn(hydet-en)2–NC–Ni(CN)2–CN–Zn(hydet-en)2– in which the zinc(II) and nickel(II) atoms are linked to each other by the cyano groups. The shift and splitting of the cyano stretching vibration is also evidence for the formation of cyano bridges. The nickel atom has a square-planar arrangement with four cyanide-carbon atoms where two cyano groups are in terminal position and two further ones in a bridging position. The Zinc atom has a distorted octahedral arrangement with two cyano and two hydet-en ligands. Both cyano and hydet-en ligands act as N-donor ligands and ethanol groups of the hydet-en ligand are not involved in the coordination. The NH, NH2 and OH groups of the hydet-en ligand are involved in intra- or intermolecular hydrogen bonding.

A vibrational spectroscopic study of Hofmann-type complexes of 3- and 4-methylpyridines

Abstract The FT-IR and Raman spectra of eight new Hofmann-type complexes of 3- and 4-methylpyridine, ML2Ni(CN)4 (M = Mn, Fe, Co or Zn; L = 3- or 4-methylpyridine) are reported. The structure consists of corrugated polymeric layers of [MNi(CN)4]∞ with methylpyridine molecules bound directly to the metal (M). For a given ligand (3-Mepy or 4-Mepy) the effects of metalligand bond formation on the ligand modes are examined and the metal sensitivity sequence of the ligand frequencies is found to be Mn

Synthesis, structural and computational characterization of 2-amino-3,5-diiodobenzoic acid and 2-amino-3,5-dibromobenzoic acid

The benzoic acid compounds 2-amino-3,5-dibromobenzoic acid (2A35Br) and 2-amino-3,5-diiodobenzoic (2A35I) acid have been synthesized and characterized by single-crystal X-ray diffraction, FT-IR spectroscopy, UV-Vis spectroscopy and computational methods. Molecular geometry, intra- and inter-molecular interactions have been investigated by using X-ray diffraction technique. Fundamental vibrational bands of the title compounds were founded by FT-IR and UV-Vis method was used to obtain electronic bands. Geometry optimizations and the calculation of IR frequencies were performed both Gaussian type orbitals at Gaussian 09W and Slater type orbitals at ADF2009.01 software. The calculations are compatible with the experiment results. In addition, geometrical parameters, energies, HOMO-LUMO gaps and electrophilicity indexes have been calculated for thirty possible positional isomers of 2A35Br and 2A35I. Calculations show that 2A35Br and 2A35I isomers have the lowest energy, the narrowest HOMO-LUMO gap and the highest electrophilicity index values. Molecular electrostatic potential maps, Fukui indices, natural bond orbital analysis, thermodynamic parameters and non-linear optical properties of the 2A35Br and 2A35I were also investigated by theoretical calculations.

Di­aqua­bis­(pyridine-2-carbox­amide-κ2N1,O2)­nickel(II) disaccharinate tetrahydrate

In the crystal structure of the title compound, [Ni(C 6 H 6 N 2 O) 2 -(H 2 O) 2 ](C 7 H 4 NO 3 S) 2 . 4 H 2 O or [Ni(pia)2(H 2 O) 2 ](sac) 2 .4H 2 O (pia is picolinamide or pyridine-2-carboxamide, and sac is the saccharinate anion), the Ni 2+ cation, located on a centre of symmetry, is coordinated by two symmetry-related aqua ligands together with a pair of symmetry-related bidentate pia molecules and exhibits a distorted octahedral environment. The unique unligated sac anion in the asymmetric unit resides on a general position and has a single negative charge. The coordinated water molecules link the sac ions to the metal complex via O-H...O hydrogen bonds. In addition, the sac ions are linked to the metal complex via intermolecular π-π interactions between the benzene ring of the sac ion and the pyridine ring of a pia ligand. Each uncoordinated water molecule is hydrogen bonded to sac moieties through OH...O and O-H...N hydrogen bonds.

Structural, spectroscopic and voltammetric studies of bis(acetazolamido)bis(aquo)bis(nicotinamide)copper(II).

Polymeric copper(II) complex, [Cu(Hacm)(2)(na)(2)(H(2)O)(2)] [H(2)acm; acetazolamide, na; nicotinamide] was synthesized and characterized by spectroscopic (IR; infrared spectroscopy, EPR; electron paramagnetic resonance), structural (XRD) and voltammetric structural (CV) methods. The copper(II) compound crystallizes in the triclinic space group P1¯, Z=1, with the unit-cell dimensions: a=7.672 (5)Å, b=8.681 (5)Å, c=11.938 (5)Å, α=90.807 (7)°, β=98.616 (5)° and γ=110.647 (5)°. The Cu(II) ion has a distorted octahedral coordination geometry. The crystal packing of the complex is stabilized by intermolecular O-H…O and N-H…O hydrogen bonds. The powder EPR spectrum of copper(II) complex have indicate that the paramagnetic center is in a tetragonal symmetry with the Cu(2+) ion having a distorted octahedral geometry. The vibrational investigation has been carried out on the basis of some characteristic IR bands of acetazolamide and nicotinamide molecules.

trans-Bis(2-benzoyl­benzoato-κO1)bis­(ethanol-κO)bis­(1H-imidazole-κN3)nickel(II)

In the title centrosymmetric mononuclear nickel(II) complex, [Ni(C14H9O3)2(C3H4N2)2(CH3CH2OH)2], the central NiII ion lies on an inversion centre and is octahedrally coordinated. The equatorial plane is formed by two O atoms from two symmetry-related 2-benzoylbenzoate ligands and two N atoms from two symmetry-related imidazole ligands, whereas the axial positions are occupied by two O atoms from two ethanol ligands. Intramolecular O---H...O hydrogen bonds stabilize this arrangement. The molecules are linked into chains running along the b axis by N—H⋯O hydrogen bonds.

Bis­(benzimidazole-κN3)bis(2-benzoyl­benzoato-κO)copper(II)

In the title centrosymmetric mononuclear copper(II) compound, [Cu(C14H9O3)2(C7H6N2)2], the central CuII ion is coordinated by two N atoms from two symmetry-related benzimidazole (bim) ligands and two O atoms from two symmetry-related 2-benzoylbenzoate (2-byba) ligands in a square-planar geometry. The molecules are linked into chains running along the b axis by N—H⋯O hydrogen bonds and the chains are cross-linked by C—H⋯π interactions.

cis-Bis(butyl-amine-κN)bis-[sulfa-diazine(1-)-κN,N']copper(II) penta-hydrate.

In the title compound {systematic name: cis-bis[4-amino-N-(pyrimidin-2-yl)benzenesulfonamidato-κ2 N,N′]bis(butylamine-κN)copper(II) pentahydrate}, [Cu(C10H9N4O2S)2(C4H11N)2]·5H2O or [Cu(sdz)2(ba)2]·5H2O [ba is butylamine and sdz = sulfadiazine(1−)], the copper(II) cation is six-coordinated by four N atoms of two sulfadiazine ligands and two N atoms of butylamine ligands. The copper(II) ion and one of the water molecules lie on twofold rotation axes. One of the butyl groups is disordered over two sites, with occupancies of 0.395 (8) and 0.605 (8). The geometry around the S atom is distorted tetrahedral. The crystal structure involves intermolecular N—H⋯N and N—H⋯O hydrogen bonds. N—H⋯N hydrogen bonds between sdz ligands lead to a sheet structure parallel to the ab plane.

Supramolecular structure constructed by coordination dimer of pyromellitate ligand

The mixed-ligand coordination dimer [Mn 2 (H 2 O) 2 (Hpm) 2 (ina) 2 ].H 2 O (Hpm=trianion of pyromellitic acid, ina=isonicotinamide) was investigated predominantly with regard to supramolecular architecture in the crystal packing. The structural properties of the complex were characterized by X-ray diffraction (XRD) technique and Fourier transform infrared (FTIR) spectroscopy. The [Hpm]3anion bridges Mn(II) ions with a tridentate coordination mode through its carboxylate groups in cis positions. In the formation of the 1D chain structure in the complex, the amide group of the ina ligand and the aqua ligand are involved in DD:AA type H-bonding with the COOgroup of [Hpm] 3. The FT-IR investigation of the complex was performed within the mid-IR region, mainly focusing on the characteristic vibrations of pyromellitic acid and isonicotinamide moieties by considering their free states and ligand behaviour in the case of complex formation.

Coordination dimer of pyromellitic acid based on supramolecular architecture

Mixed-ligand coordination dimer [Ni2(H2O)4(H2pm)(ina)2] (H2pm=dianion of pyromellitic acid, ina=isonicotinamide) was investigated mainly from the point of supramolecular architecture in their respective crystal packings. The structural properties of complex were characterized by X-ray diffraction (XRD) technique and Fourier transform infrared (FT-IR) spectroscopy. Each [H2pm] 2anion adopts a μ2-bridging mode to connect with two Ni(II) ions through its carboxylate O atoms. The discrete coordination dimers are connected by H-bond dimers involving N–H∙∙∙O interactions between the amide groups of adjacent ina ligands. In addition, these H-bonded chains are interconnected by O–H∙∙∙O bonds formed by DA:AD type organization of aqua ligands. The FT-IR investigation of the complex was performed within the mid-IR region, mainly focusing on the characteristic vibrations of pyromellitic acid and isonicotinamide moieties by considering their free states and ligand behaviour in the case of complex formation.