Results 121 to 130 of about 23,032 (162)

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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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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Nitrogen superhyperfine splittings of vanadyl porphyrins in native asphaltenes

Die Naturwissenschaften, 1971
T F Yen
exaly   +2 more sources

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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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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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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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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Electron Spin Resonance of Some Vanadyl Porphyrins

The Journal of Chemical Physics, 1961
The electron spin resonance spectra of the vanadyl complexes of etioporphyrin II, vanadyl mesoporphyrin IX dimethyl ester, and deuteroporphyrin IX dimethyl ester have been studied and found to be identical to within experimental error. Unlike the corresponding copper complexes, the vanadyl complexes give no observable nitrogen hyperfine effects.
E. M. Roberts, W. S. Koski, W. S. Caughey   +2 more
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Vanadyl porphyrins in crude oil and vacuum gasoil

Chemistry and Technology of Fuels and Oils, 1986
The authors have segregated vanadyl porphyrins from mixed West Siberian crudes and from the corresponding gasoil (350-500/sup 0/C) by a combined extraction-chromatographic method in order to establish their composition. The vanadyl porphyrin concentrations were determined spectrophotometrically according to the intensities of the absorption band at 570
N. I. Shilonosova, O. V. Serebrennikova, L. V. Ryadovaya   +2 more
openaire   +1 more source