17O-ligand hyperfine structure in single crystal ESR spectra of copper(II)hydroxyquinolinate: phthalimide and copper(II)picolinate:zincpicolinate tetrahydrate

K-band ESR spectra of ¹⁷O labelled Copper(II)oxyquinolinate (CuOX₂) substituted in phthalimide single crystals and of Copper(II)picolinate (Cupic₂) substituted in single crystals of Zinc picolinate tetrahydrate are reported. The spectra were analyzed as a superposition of spectra of 3 isotopic ¹⁶O, ¹⁷O species, yielding anisotropic hyperfine coupling tensors for the ¹⁷O ligands of the two complexes. The magnetic data will then be used for derivation of bonding parameters in a one hole MO scheme and of spin densities at oxygen ligands by two different approaches π^o values of 0.13 and 0.085 (per oxygen atom) for CuOx₂ and Cupic₂ were found. f⁰_p/f⁰_s ratios amount to 11.0 and 8.7 for the two systems, respectively, thereby ranging considerably higher then found hitherto.     

ESR spectra of Cu(II) N-alkyldithiocarbamates

ESR spectra are reported for polycrystals, solutions, and glasses. In every case the -bonds are found to be substantially covalent. The identical spectra point to structural identity; the substituents affect only the spectra of polycrystals via differences in packing. The spectra are examined by MOLCAO methods and with allowance for the mixing of other d orbitals with the ground-state orbital. Both methods give similar results.     

Local structure analysis of Cu(II)-diazepam complexes by ESR spectroscopy

CuL₂X₂ (L = 7-chloro-1,3-dihydro-1-methyl-5-phenyl-3H-1,4-benzodiazepin-2-one, also known as diazepam, X = Cl, Br) complexes have been prepared and investigated by ESR spectroscopy. Powder ESR spectra of these complexes suggest a planar-rhombic distorted local symmetry. The CH₃Cl solutions spectra show the presence of pseudo-tetrahedral species with a 3d_xy+4p_z mixture ground state for the paramagnetic electron. The anisotropic spectra obtained for the Cu(II)-diazepam solution adsorbed on NaY zeolite confirm the existence of a CuN₂X₂ chromophore.     

Local structure analysis of Cu(II)-diazepam complexes by ESR spectroscopy

CuL(2)X(2) (L = 7-chloro-1,3-dihydro-1-methyl-5-phenyl-3H-1,4-benzodiazepin-2-one, also known as diazepam, X = Cl, Br) complexes have been prepared and investigated by ESR spectroscopy. Powder ESR spectra of these complexes suggest a planar-rhombic distorted local symmetry. The CH(3)Cl solutions spectra show the presence of pseudo-tetrahedral species with a 3d(xy)+4p(z) mixture ground state for the paramagnetic electron. The anisotropic spectra obtained for the Cu(II)-diazepam solution adsorbed on NaY zeolite confirm the existence of a CuN(2)X(2) chromophore.     

Single crystal ESR and ENDOR of bis-(salicylaldoximato) Cu(II): Bis-(Salicylaldoximato)Ni(II): Copper,nitrogen and proton hyperfine data and structure of the internal H-bond

An investigation of the ESR and ENDOR spectra of the complex Cusal₂ substituted into single crystals of Nisal₂ is reported. An analysis of the spectra is presented yielding g tensor, the hyperfine interaction tensors of ⁶³Cu, ¹⁴N and four protons and the quadrupole tensor of ¹⁴N, as well as the orientation of the principal axes systems of these quantities. Interpretation of the hyperfine pattern of the set of two perfectly equivalent ¹⁴N nuclei is shown to require a detailed analysis of the second order perturbation terms expressed in the coupled spin basis. For certain orientations of the crystal the ¹⁴N hyperfine pattern shows up to sixteen lines. Analysis of this phenomenon is achieved by exact diagonalization of the energy matrix and is traced back to noncrossing of energy levels. From the magnetic data bonding parameters of Cusal₂ in an extended Maki—McGarvey picture and spin densities on Cu and ¹⁴N are derived. Cusal₂ features an intramolecular hydrogen bridge of type OH…O. Based on some assumptions concerning spin densities, the experimentally determined magnetic constants and a seven-center dipole—dipole interaction model, the structure of the H-bond is inferred to be bent and nonsymmetric, with the angle ∠ OH…O lying in the range 130–143°.     

17O Hyperfine structure in single crystal ESR spectra of Cu(II) picolinate: Zn(II) picolinate-4H2O

ESR spectra of ¹⁷O modifications of Cu(II)picolinate substituted in Zn(II)picolinate-4H₂O single crystals are reported. Values of ¹⁷O hyperfine coupling tensors, orientation angles and approximate relative spin densities at the O and N nuclei are given.     

Co(II), Ni(II), and Cu(II) Complexes of N-(2-Hydroxybenzamido)phthalimide

Russian Journal of General Chemistry - Co(II), Ni(II), and Cu(II) complexes with N-(2-hydroxybenzamido)phthalimide (LH2) were synthesized and studied by IR, electron absorption, EPR spectroscopy,...     

ESR spectra studies of Cu(Ⅱ) 2,4-dihydroxybenzaldehyde tyrosine complex

A novel Schiff base derived from 2,4-dihydroxybenzaldehyde and tyrosine and its copper(Ⅱ)complex have been synthesized and characterized.The composition of the complex is K[CuL] H2O,where L=H11C16NO5.ESR spectra of the copper(Ⅱ)complex were investigated at different temperatures and in various solvents.The second order effect and the relaxation effect were observed in the solution spectrum at room temperature,which was satisfactorily explained by spin Hamiltonian.The bonding parameters of copper(Ⅱ)complex were calculated using spectral parameters from ESR spectra at low temperature.Its bonding characterization and stability were disscussed.The result shows that the in-plane a-bond and the in-plane π-bond in the complex all play an important role.     

Investigation of the hyperfine structure of TaI-line (II)

The hyperfine structure of several spectral lines of the neutral tantalum atom was investigated by means of saturated laser spectroscopy, detecting optogalvanic signals and/or laser induced fluorescence. From the spectra we could determine the magnetic hyperfine interaction constants A and the electric quadrupol interaction constants B of 11 levels of even parity and 13 levels of odd parity.     

过氧化氢酶与Cu(Ⅱ)络合的ESR谱及活性分析

用Cu(Ⅱ)对过氧化氢酶(CAT)进行修饰，制备了Cu(Ⅱ)络合的CAT，称为Cu(Ⅱ)CAT．Cu(Ⅱ)CAT除了具有CAT的活性外，还有SOD样活性．Cu(Ⅱ)CAT可以抵抗O2.-的氧化损伤作用．     

Stabilities of mixed ligand complexes of Cu(II) with ligands coordinating through O and N : ESR studies

Mixed ligand complexes of Cu(II) with 8-hydroxy-quinolinate (Hy) as one ligand and acetylacetonate (ac.ac) or salicylaldehydate (Sal) as the second ligand have been prepared in reaction mixtures of Cu(Hy)₂ + Cu(ac.ac)₂ and Cu(Hy)₂ + Cu(Sal)₂ in chloroform. Ligand hyperfine structures and the minimum ESR linewidth associated withm = − 3/2 hyperfine component have been used to detect and identify the mixed ligand complexes. The ligands in these complexes coordinate through O or N. The constantsK associated with the ligand exchange equilibriums are ~ 2 at −20°C and are close to the value expected from the empirical relation obtained in an earlier work from a study of Cu(II) complexes in which S also participates in the coordination.     

Accounting for effects of AZA-substitution on hyperfine interaction constants in ESR spectra

A previously developed scheme for describing the effects of substituents on the physicochemical characteristics of molecules with conjugated bonds has been extended to systems with an open electron shell. The distribution of spin density has been found for a number of anion radicals of azines on the basis of a calculation of their hydrocarbon analogs. The results are in agreement with experimental values of the HFI constant in the ESR spectra of these compounds.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 155–161, March–April, 1989.     

ESR study of low-spin Co(II) complexes: observation of hyperfine interaction with in-plane ligand atoms

The ESR spectra of low-spin Co(II) complexes with phosphorus-containing ligands, show clearly resolved ³¹P hyperfine interaction with the in-plane ligand atoms (ca. 20 × 10^?4 cm^?1). A ²A₁ ground state is proposed on the basis of the properties of the ³¹P hfs tensor.     

Coordination chemistry of some new Cu(II), Ni(II) and Co(II) macroacyclic (N2O4) Schiff base complexes: X-ray crystal structure of Cu(II) complex

Six new Cu(II), Ni(II) and Co(II) macroacyclic Schiff base complexes [M^II(H₂L)](ClO₄)₂ (L = L¹ and L²) (I–VI) were prepared by the reaction of two new N₂O₄ Schiff base ligands in equemolar ratios. The ligands H₂L¹ and H₂L² were synthesized by reaction of 2-[2-(2-formyl phenoxy)ethoxy]benzaldehyde (A¹) and/or 2-[2-(3-formylphenoxy)propoxy]benzaldehyde (A²) and ethanol amine and characterized with IR and ¹H, ¹³C NMR spectroscopy. All complexes were characterized by microanalysis, IR and mass spectrometry, whereas complex I was also characterized by single crystal X-ray (CIF file CCDC no. 1020055). The X-ray structure of complex I revealed that all nitrogen and oxygen atoms of ligand (N₂O₄) have coordinated to the metal ion. However, Cu²⁺ ion is in six coordination environment that can bedescribed as a distorted octahedral geometry.