Bünyamin Karabulut

EPR study of gamma irradiated arsanilic acid single crystal

Abstract EPR spectra of gamma irradiated arsanilic acid single crystal shows rarely observed and unstable arsenate centred [(OH) 2 As=O] radical. There are two magnetically distinct sites in monoclinic lattice. The principal hyperfine and g values of both sites are determined from spectra taking the large hyperfine effects into account. The principal hyperfine values are found to be A x =602, A y =437 and A z =428 Gauss for one site and A x =602, A y =438 and A z =429 Gauss for the other site. The g values of both sites are the same with the values g x =2.048, g y =2.001 and g =2.000. The radical is in slightly distorted C 3v symmetry. The unpaired electron is mainly localised on s orbitals of O atoms and partly on p orbital of central As atom. Calculations of EPR parameters for large hyperfine values are discussed and some easily applicable numerical techniques are utilised.

EPR studies of Cu2+-doped bis(saccharinato)bis(pyridine)zinc(II) single crystals

The electron paramagnetic resonance spectra of Cu2+ impurities in bis(saccharinato)bis(pyridine)zinc(II) single crystals have been studied at room temperature in three mutually perpendicular planes. The angular variation of the spectra indicates the substitution of the host Zn2+ with Cu2+. Two magnetically inequivalent sites for Cu2+ have been observed. The spectra were fitted to the rhombic spin Hamiltonian. The spin Hamiltonian parameters and the molecular orbital coefficients were evaluated for the two sites. The ground-state wave function of Cu2+ ion in the lattice has been constructed.

Crystal structure and EPR studies of mixed ligand complex of cobalt(II) with saccharin and ethylisonicotine

The tetraaquabis(ethylisonicotinate)cobalt(II) disaccharinate, [Co(ein)2(H2O)4].(sac)2, (CENS), (ein: ethylisonicotinate and sac: saccharinate) complex has been synthesized and its crystal structure has been determined by X-ray diffraction analysis. The title complex crystallizes in monoclinic system with space group P2(1)/c and Z=2. The Co(II) cations present a slightly distorted CoN2O4 octahedral environment, with equatorially coordinated water molecules and axially pyridine N-bound ethylisonicotinate ligands. The magnetic environments of Cu2+-doped Co(II) complex have been identified by electron paramagnetic resonance (EPR) technique. Cu2+-doped CENS single crystals have been studied at room temperature in three mutually perpendicular planes. The calculated results of the Cu2+-doped CENS indicate that Cu2+ ion substitute with the Co2+ ion in the host lattice. The angular variations of the EPR spectra have shown that two different Cu2+ complexes are located in different chemical environments, and each environment contains two magnetically inequivalent Cu2+sites in distinct orientations occupying substitutional positions in the lattice and show very high angular dependence. The cyclic voltammogram of the title complex investigated in dimethylformamide (DMF) solution exhibits only metal centered electroactivity in the potential range -1.0-1.25V versus Ag/AgCl reference electrode.

Structural, spectroscopic and EPR studies of tetraethylammonium tetramethylammonium tetrabomocuprate (II) complex

Abstract The tetraethylammonium tetramethylammonium tetrabromocuprate(II), (hereafter, [(TEA)(TMA)CuBr4]) [(C2H5)4N][(CH3)4N][CuBr4], complex was synthesized and characterized by spectroscopic (IR), structural (XRD) and electron paramagnetic resonance (EPR) technique. The compound contains four isolated and discrete moieties, i.e. two independent [(CH3)4N]+ cations, with one on a -4 axis and the other with the central N atom on a 2z axis, one [(C2H5)4N]]+ cation, on a mirror plane and in a trans conformation, and one distorted tetrahedral [CuBr4]2– anion on another mirror plane. The electron paramagnetic resonance spectra of [(TEA)(TMA)CuBr4] single crystals and powder were investigated in the temperature range from 300 to 5 K. The observed values from the line width and g tensors were found to be temperature dependent. The temperature dependence of Cu(II) complex with EPR spectra values were also discussed in terms of dynamic Jahn-Teller effect.

An EPR and optical absorption study of Cu2+ doped in disodium malonate trihydrate single crystal

Single crystals and powder electron paramagnetic resonance (EPR) studies of Cu(2+)-doped disodium malonate trihydrate [C(3)H(2)O(4)Na(2).3H(2)O] have been carried out at room temperature. The angular variation of the disodium malonate trihydrate single crystal have shown that two different Cu(2+) complexes are located in different chemical environments, and each environment contains one magnetically inequivalent Cu(2+) sites in distinct orientations occupying substitutional positions in the lattice and show very high angular dependence. The principal values of the g and the hyperfine tensors were determined and were found to be in agreement with the literature values. Crystal field around the Cu(2+) ion is nearly rhombic. The optical absorption studies show two bands at 603nm (16584cm(-1)) and 890nm (11236cm(-1)) which confirm the rhombic symmetry. The crystals field parameters and than the wave function are determined.

EPR study of Cu2+-doped tetraaqua-di(nicotinamide)Co(II) saccharinate single crystals

The electron paramagnetic resonance spectra of Cu(2+) impurities in [Co(nicotinamide)(2)(H(2)O)(4)](saccharinate)(2) single crystals have been studied at ambient temperature in three mutually perpendicular planes. The angular variation of the spectra shows that the Cu(2+) ion substitutes the Co(2+) site in the lattice. The EPR spectra of Cu(2+) ions are characteristic of tetragonally elongated octahedral site. The spin-Hamiltonien parameters were obtained from the single crystal EPR analysis. The ground-state wave function of Cu(2+) ion in the lattice has been constructed.

Synthesis and properties of 1,5-dithio-3-oxa-pentanediyl bridged polymeric phthalocyanines

Abstract Oxa-thio bridged metal-free and metal phthalocyanine polymers were prepared. Metal-free phthalocyanine polymer (H 2 Pc) and metal phthalocyanine polymers (Ni, Cu, Co, Zn or Fe) carrying dithio-oxa bridged were synthesized from 3,3′-4,4′-tetracyanodiphenyl-1,5-dithiopenanyl-oxa-ether and hydroquinone or the corresponding anhydrous metal salts [NiCl 2 , CuCl, CoCl 2 , Zn(CH 3 CO 2 ) 2 or Fe(CO) 5 ]. The model phthalocyanine compounds were characterized by IR, UV/VIS and DTA. The electrical conductivities of the phthalocyanines measured as gold sandwiches are about 10 −10 Sm −1 in vacuo and in air.

Electron paramagnetic resonance of Cu2+ in Na3PO4·8H2O single crystal

The electron paramagnetic resonance spectra of Cu2+ in an Na3PO4·8H2O single crystal were studied at room temperature. The spectra indicate the presence of two magnetically inequivalent sites and monoclinic symmetry of the crystal. The principal values of the g and the hyperfine tensors were determined and were found to be in agreement with the literature values. It is proposed that the Cu2+ ions replace the Na+ ions, and the charge compensation is fulfilled by the charge of a nearby proton vacancy of the coordinating water molecules. The ground state wavefunction of the Cu2+ is thought to be an admixture of the 3dx2−y2 and 3dz2 orbitals and the admixtures of the two magnetically inequivalent sites were obtained.

An EPR Study of Cu2+ Doped Sodium Hydrogen Oxalate Monohydrate Single Crystal

Abstract The EPR spectra of Cu2+ in Sodium hydrogen oxalate monohydrate, NaHC2O4.H2O(SHOMH hereafter) single crystal was studied at room temperature. The angular variation of EPR spectra showed that the Cu2+ ion in SHOMH single crystal substitutes with Na+ monovalent cation together with a monovalent vacancy to compensate oxygen in the crystal. Since the crystal symmetry is triclinic, only one site is observed in the EPR spectra in three perpendicular axis. The spin Hamiltonian parameters were obtained, and the ground state wave function of Cu2+ ion in the lattice was constructed.

EPR and optical studies of vanadium doped potassium dihydrogen citrate (C6H7KO7) single crystal

An EPR and optical studies of VO2+ doped potassium dihydrogen citrate (PDHC) single crystals have been carried out at room temperature. It crystallizes in triclinic symmetry with the unit cell dimensions: a=11.343Å, b=13.078Å, c=6.272Å, α=89.79°, β=94.36°, γ=104.2°. The angular variation of EPR spectra have shown that two different VO2+ complexes are located in different chemical environments and each environment contains one magnetically VO2+ site occupying substitutional position in the lattice and show very high angular dependence.