Results 131 to 140 of about 370 (171)

Comparison of nickel and vanadyl porphyrin distributions of sediments

Geochimica et Cosmochimica Acta, 1993
Abstract The distributions of nickel and vanadyl porphyrins of Toarcian shale, northern Germany, and the Monterey Formation, California, were examined. The compositions of nickel and vanadyl porphyrin fractions of extracts from the same sample show substantial differences.
Padmanabhan Sundararaman, Christopher J. Boreham   +1 more
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The interaction of vanadyl porphyrin with the HY zeolite surface

Journal of Molecular Catalysis A: Chemical, 2009
The interaction of vanadyl porphyrin with the acid sites of the HY zeolite surface is investigated. Structural changes, partial population charges and relative energies induced by the interaction between vanadyl porphyrin and the zeolite surface are estimated with recourse to the Born-Oppenheimer semiclassical molecular dynamics technique in ...
I.P. Zaragoza, R. Santamaria, R. Salcedo
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ChemInform Abstract: Electrochemistry of Vanadyl Porphyrins in Dimethylformamide.

ChemInform, 1988
AbstractElectrode reactions of (I) are monitored in DMF by cyclic voltammetry, rotating‐disk voltammetry, and spectroelectrochemistry.
K. M. KADISH, D. SAZOU, C. ARAULLO, Y. M. LIU, A. SAOIABI, M. FERHAT, R. GUILARD   +6 more
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Vanadyl Tetrakis(pentafluorophenyl)porphyrin Dichloromethane Solvate

Acta Crystallographica Section C Crystal Structure Communications, 1998
The vanadyl complex oxo[5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato-κ 4 N]vanadium(IV) dichloromethane solvate, [VO(C 44 H 8 F 20 N 4 )].CH 2 Cl 2 , crystallizes in the monoclinic space group P2 1 /c, with four molecules per unit cell. The V atom is found to lie . 0.5237 (5) A above the mean plane of the porphyrin core.
H. Duval, V. Bulach, J. Fischer, R. Weiss   +3 more
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Redox chemistry of water-soluble vanadyl porphyrins

Journal of Photochemistry, 1987
Abstract In aqueous solution, pulse radiolytic studies have shown that vanadyl porphyrins undergo redox reactions only at the porphyrin ring. The resultant porphyrin radical anions and cations are unstable with respect to disproportionation. Steady state reduction, both radiolytic and photochemical, of the vanadyl porphyrins results in formation of ...
Peter Hambright, Pedatsur Neta, Marie-Claude Richoux, Zeinab Abou-gamra, Anthony Harriman   +4 more
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Liquid chromatography-mass spectrometry of vanadyl porphyrins

Organic Geochemistry, 1993
Abstract A mixture of vandyl porphyrins was analysed by liquid chromatography-mass spectrometry using a particle beam interface. The resolution of the chromatogram in the LC-MS mode is comparable to that obtained using a u.v.-vis spectrophotometric detector, but the sensitivity was much lower.
Padmanabhan Sundararaman, Christina Vestal   +1 more
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Modelisation of the interactions of vanadyl porphyrins with hydroprocessing catalysts

Physica B: Condensed Matter, 1989
Abstract This paper first compares the X-ray Fluorescence excitation spectra of several vanadyl porphyrins which differ by the nature of appended functional groups. The aim of these investigations was to check whether structural distortions associated with chemical modifications of the porphyrin ligand can be detected from the EXAFS spectra and ...
M. Loos, I. Ascone, P. Friant, J. Goulon, N. Senglet, J.M. Barbe, R. Guilard, D. Faure   +7 more
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Crystal and molecular structure of a natural vanadyl porphyrin

Australian Journal of Chemistry, 1984
The crystal and molecular structure of a vanadyl deoxophylloerythroetioporphyrin (dpep) extracted from oil shale has been determined by single crystal X-ray diffraction. The compound crystallizes in space group P21/c of the monoclinic system with four formula units in a cell of dimensions a 12.912(3), b 14.151(4), c 18.404(8) Å, ß 70.34(2)º.
SA Miller, TW Hambley, JC Taylor
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Magnetooptic activity and symmetry of petroleum vanadyl porphyrins

Russian Physics Journal, 1992
We report magnetooptic rotation and magnetic circular dichroism spectra in the vicinity of the absorption bands at 17410 cm−1 and 16760 cm−1 in chloroform solutions of petroleum vanadyl porphyrin. Using the moment method, we estimate the original splitting and the z-component of the magnetic moment of the 11E1u level for both synthetic and petroleum ...
A. A. Latyshev, V. N. Medvedev, V. O. Nekuchaev   +2 more
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Titanylation and vanadylation of highly π-conjugated porphyrins

Tetrahedron Letters, 2014
Abstract We report the efficient synthesis of tetrabicycloporphyrin titanyl and vanadyl without decomposition of the bicyclo[2.2.2]octadiene unit. The complexes were heated under vacuum to give titanyl and vanadyl tetrabenzoporphyrins in 100% yield.
Satoshi Ito, Takahiro Ito, Daishi Makihata, Yutaro Ishii, Yuki Saito, Toru Oba   +5 more
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