Extra absorption peaks in EPR spectra of systems with anisotropic g-tensor and hyperfine structure in powders and glasses

Овчинников, И. В.; Konstantinov, V. N.

doi:10.1016/0022-2364(78)90203-2

Cited by 43 publications

(32 citation statements)

References 4 publications

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“…In conjunction with the high nuclear spin quantum number I = 5/2, this situation favors the appearance of the extra lines in the powder spectrum ( Fig. 1f), when the following inequalities are satisfied [39]:…”

Section: Epr Spectroscopy Of Surface Superoxide Speciesmentioning

confidence: 97%

Diagnostic Features of EPR Spectra of Superoxide Intermediates on Catalytic Surfaces and Molecular Interpretation of Their g and A Tensors

et al. 2015

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The use of electron paramagnetic resonance spectroscopy to study the superoxide intermediates, generated by end-on and side-on adsorption of the naturally abundant and 17 O-enriched dioxygen on catalytic surfaces is discussed. Basic mechanisms of O 2 -radical formation via a cationic redox mechanism, an anionic redox mechanism, and an electroprotic mechanism are illustrated with selected oxide-based systems of catalytic relevance. Representative experimental spectra of various complexities are analyzed and their diagnostic features have been identified and interpreted. The molecular nature of the g and A tensors of the electrostatic and covalent superoxide adducts is discussed in detail within the classic and density functional theory based approaches.

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Section: Epr Spectroscopy Of Surface Superoxide Speciesmentioning

confidence: 97%

Diagnostic Features of EPR Spectra of Superoxide Intermediates on Catalytic Surfaces and Molecular Interpretation of Their g and A Tensors

et al. 2015

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“…The line at the high-field end of the spec trum of compound 1 (Fig. 1) is an extra absorp tion peak that appears sometimes in addition to the lines obtained with the applied magnetic field par- allel or perpendicular to the symmetry axis [13].…”

Section: Resultsmentioning

confidence: 97%

New Coordination Compounds Derived from Nitrone Ligands: Copper(II) Complexes with 8-Hydroxyquinoline-2-carbaldehyde- and Pyridine-2-carbaldehyde-N-methylnitrones

Petkova

Domasevitch

Gorichko

et al. 2001

Zeitschrift Für Naturforschung B

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New copper(II) complexes with 8-hydroxyquinoline-2-carbaldehyde-N-methylnitrone (HL1) (1) and pyridine-2-carbaldehyde-N-methylnitrone (L2) (2) have been synthesized. The crystal structure of compound 1 consists of binuclear molecules Cu2(L1)2(NO3)2 with the oxygen atoms of the hydroxy groups acting as bridges between the copper ions. The nitrone ligand in 1 is coordinated in a tridentate fashion forming five-and six-membered chelate rings, and the copper ions have a square-pyramidal environment with the bridging oxygen atoms in apical positions. In compound 2 Cu(L2)2(NO3)2, the copper atom adopts a distorted octahedral environment with bidentately coordinated nitrone ligands. In both cases the nitrone groups are involved in coordination via the oxygen atom. Compounds 1 and 2 have been studied by EPR, UV-VIS and IR spectroscopy. The free nitrone HL1 has also been studied by X-ray diffraction as well as by IR and UV spectroscopy.

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“…However, computer modeling revealed some anisotropy of the g and A tensors in the xy plane. The spectra show a well-resolved HFS due to 63 Cu or 65 Cu (I = 3/2) nuclei (I = 3/2) in all the three orientations and an additional high-field peak of a high intensity [39,40] (Fig. 1).…”

Section: Resultsmentioning

confidence: 99%

Structural Organization of Nickel(II), Zinc(II), and Copper(II) Complexes with Diisobutyldithiocarbamate: EPR, 13C and 15N CP/MAS NMR, and X-Ray Diffraction Studies

et al. 2005

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Dithiocarbamate complexes of transition metals have found wide use in various areas of practical activity [1]. For coordination chemistry, dialkyldithiocarbamates are of interest as ligands with different structural functions (monodentate, terminal bidentate, bridging bidentate, and mixed), which allows their complexes to be structurally organized in a variety of types (mono-, bi-, tri-, and, in the general case, polynuclear). Mononuclear centrosymmetric nickel(II) complexes with dithiocarbamate ligands [Ni ( S 2 CNR 2 ) 2 ] [2-18] contain the terminal dithiocarbamate groups coordinated by nickel in a bidentate manner through two sulfur atoms to give small planar four-membered chelate rings [NiS 2 C] (R = CH 3 [2], C 2 H 5 [3-5], C 3 H 7 [6, 7], i -C 3 H 7 [8], C 4 H 9 [9, 10], i -C 4 H 9 [9, 11], and C 2 H 5 O [12] or R 2 = ( CH 2 ) 4 [13], ( CH 2 ) 5 [14], ( CH 2 ) 6 [7, 15, 16], C 6 H 5 and CH 3 CO [17], and CH 3 and C 6 H 5 [18]). In contrast to nickel, zinc forms binuclear molecular structures [Zn 2 ( S 2 CNR 2 ) 4 ] [19-31] (R = CH 3 [19, 20], C 2 H 5 [21-23], C 3 H 7 [24], i -C 3 H 7 [25], C 4 H 9 [26], and CH 2 CH = CH 2 [27] or R 2 = ( CH 2 ) 4 [28], ( CH 2 ) 6 [29] , CH 3 and C 2 H 5 , CH 3 and C 3 H 7 , CH 3 and i -C 3 H 7 , CH 3 and C 4 H 9 [30], and C 2 H 5 and cyclo -C 6 H 11 [31]), in which the dithiocarbamate ligands are structurally nonequivalent in pairs. Two of them, namely, terminal bidentate ligands, form four-membered chelate rings [ZnS 2 C], while the other two (bridging ligands) connect the adjacent Zn atoms. The resulting dimer includes an elongated nonplanar eight-membered chelate ring [Zn 2 S 4 C 2 ] in the chair [21-25, 27-31] or tub conformation [19,20,26]. The coordination polyhedron of the zinc atom is a distorted tetrahedron or a trigonal bipyramid composed of sulfur atoms. The only exception is the mononuclear dicyclohexyldithiocarbamate complex [Zn { S 2 CN ( c -C 6 H 11 ) 2 } 2 ] with a tetrahedral structure [31]. (The presence of the two bulky cycloalkyl substituents in the ligand makes it sterically impossible to form a binuclear molecular structure.) However, dithiocarbamate complexes containing ligands with long-chain alkyl substituents have been poorly studied to date, although they can be of the greatest practical interest (as molecular precursors of film metal sulfides) because the molecular volatility in a vacuum increases with a lengthening of the hydrocarbon chain of a substituent.The goal of this study was to obtain nickel(II), zinc(II), and copper(II) complexes with diisobutyl-and dibutyldithiocarbamate and compare their structural organizations.EXPERIMENTAL Nickel(II) and zinc(II) complexes with dibutyl-(BDtc) and diisobutyldithiocarbamate ( i -BDtc) I -III were obtained by reactions of aqueous solutions of NiCl 2 · 6 H 2 O and ZnCl 2 with the corresponding sodium dithioAbstract -The structures and spectroscopic properties of nickel(II), zinc(II), and copper(II) complexes with dibutyl-and diisobutyldithiocarbamate were studied by EPR and 13 C and 15 N CP/MAS NMR spe...

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Extra absorption peaks in EPR spectra of systems with anisotropic g-tensor and hyperfine structure in powders and glasses

Cited by 43 publications

References 4 publications

Diagnostic Features of EPR Spectra of Superoxide Intermediates on Catalytic Surfaces and Molecular Interpretation of Their g and A Tensors

Diagnostic Features of EPR Spectra of Superoxide Intermediates on Catalytic Surfaces and Molecular Interpretation of Their g and A Tensors

New Coordination Compounds Derived from Nitrone Ligands: Copper(II) Complexes with 8-Hydroxyquinoline-2-carbaldehyde- and Pyridine-2-carbaldehyde-N-methylnitrones

Structural Organization of Nickel(II), Zinc(II), and Copper(II) Complexes with Diisobutyldithiocarbamate: EPR, 13C and 15N CP/MAS NMR, and X-Ray Diffraction Studies

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