Metalloporphyrin .pi.-Cation Radicals. Molecular Structure and Spin Coupling in a Vanadyl Octaethylporphyrinate Derivative. An Unexpected Spin Coupling Path

1994 ◽  
Vol 116 (16) ◽  
pp. 7196-7203 ◽  
Author(s):  
Charles E. Schulz ◽  
Hungsun Song ◽  
Young Ja Lee ◽  
Jalal U. Mondal ◽  
K. Mohanrao ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Spin Coupling ◽  
Cation Radicals ◽  
Coupling Path

Nuclear spin-spin coupling via nonbonded interactions. 7. Effects of molecular structure on nitrogen-fluorine coupling

1992 ◽  
Vol 57 (1) ◽  
pp. 366-370 ◽  
Author(s):  
Frank B. Mallory ◽  
Eddie D. Luzik ◽  
Clelia W. Mallory ◽  
Patrick J. Carroll
Keyword(s):  
Molecular Structure ◽  
Nuclear Spin ◽  
Spin Coupling ◽  
Nonbonded Interactions ◽  
Spin Spin Coupling

Spin coupling in Cu porphyrin π-cation radicals

1989 ◽  
Vol 199 ◽  
pp. 137-148 ◽  
Author(s):  
W.Daniel Edwards ◽  
Geerd H.F. Diercksen ◽  
Michael C. Zerner
Keyword(s):  
Spin Coupling ◽  
Cation Radicals

The Molecular Structure of Allenes and Ketenes, XIII Correlations of Carbon-Proton Spin-Spin Coupling Constants in Allenes with ab initio STO-3G Overlap Populations

1979 ◽  
Vol 34 (1) ◽  
pp. 118-120 ◽  
Author(s):  
Wolfgang Runge
Keyword(s):  
Molecular Structure ◽  
Ab Initio ◽  
Substituent Effects ◽  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Proton Coupling ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Cl Atoms

Abstract It is shown that substituent effects on one-bond and long-range carbon-proton coupling constants in monosubstituted allenes parallel quantitatively ab initio STO-3G carbon 2s-hydrogen 1 s overlap populations, irrespectively of whether the substituents are bonded to the allenic skeleton via first-row (C, O) or second-row (Si, S, Cl) atoms.

INDO Molecular Orbital Calculations of Nuclear Spin–Spin Coupling Constants Over Three Bonds Between 13C and 1H in Some Simple Molecules

1973 ◽  
Vol 51 (6) ◽  
pp. 961-973 ◽  
Author(s):  
R. Wasylishen ◽  
T. Schaefer
Keyword(s):  
Dihedral Angle ◽  
Molecular Orbital ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Molecular Orbital Calculations ◽  
Methyl Proton ◽  
Coupling Path ◽  
Spin Coupling Constants ◽  
Simple Molecules ◽  
Spin Spin Coupling

Molecular orbital calculations, at the INDO level, of the spin–spin coupling constants over three bonds between carbon-13 and protons are reported for a number of simple molecules. In propane the coupling depends on dihedral angle in the Karplus manner. Fluorine substituents cause changes in the computed coupling which are best described as alternating with the number of bonds intervening between the substituent and the coupled nuclei. Finer details of this phenomenon are discussed and calculations on propyllithium are performed. Replacement of a central carbon atom in propane by a heteroatom does not radically alter the computed couplings. The presence of a carbonyl group in the coupling path results in an overestimate of the magnitude of the coupling. In propene the coupling between 13C in position 1 and a methyl proton displays a maximum when the C—H bond of the methyl group lies parallel to the π orbitals. In toluene the coupling to a methyl proton is insensitive to the dihedral angle over half its range, a result of importance to structural studies. Among other molecules under consideration are methylacetylene, propionaldehyde, and the strained bicyclobutane. It is suggested that in certain instances the mean of the predictions from the INDO and CNDO/2 procedures may agree better with experiment than will the prediction from either procedure alone. Calculations on fluorobenzene and 1,2-difluorobenzene suggest that the main experimental trends of the couplings between carbon and protons within the benzene ring are reproduced. Such is perhaps not true for the five-membered heterocycles.

9-Borafluorenes – NMR spectroscopy and DFT calculations. Molecular structure of 1,2-(2,2′-diphenylylene)-1,2-diethyldiborane

2010 ◽  
Vol 75 (7) ◽  
pp. 743-756 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Peter Thoma ◽  
Rhett Kempe ◽  
Germund Glatz
Keyword(s):  
Molecular Structure ◽  
Nmr Spectroscopy ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spin Coupling ◽  
X Ray Diffraction ◽  
Data Set ◽  
Chemical Shift Tensors ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

9-Borafluorene derivatives 1 (9-R = Et (a), Ph (b), Cl (c), NEt2 (d)), the pyridine adduct 1py+ and 1,2-(2,2′-biphenylylene)-1,2-diethyldiborane(6) (3), were studied by 11B and 13C NMR spectroscopy to obtain a fairly complete data set for the first time. The molecular structure of the doubly hydrogen-bridged 1,2-diphenylenediborane 3 was determined by X-ray diffraction. The gas-phase structures of the compounds 1, related derivatives, and of some doubly hydrogen-bridged 1,2-diphenylenediboranes were optimized by quantum chemical calculations (B3LYP/6-311+G(d,p) level of theory) and NMR parameters, such as chemical shifts, 11B chemical shift tensors and indirect nuclear 13C–11B spin–spin coupling constants were calculated at the same level of theory and compared with experimental data.

ChemInform Abstract: Spin Coupling in Metalloporphyrin π-Cation Radicals.

ChemInform ◽  
1987 ◽  
Vol 18 (36) ◽  
Author(s):  
B. S. ERLER ◽  
W. F. SCHOLZ ◽  
Y. J. LEE ◽  
W. R. SCHEIDT ◽  
C. A. REED
Keyword(s):  
Spin Coupling ◽  
Cation Radicals

Oxoferryl porphyrin cation radicals in model systems: Evidence for variable metal-radical spin coupling

1990 ◽  
Vol 58 (1-4) ◽  
pp. 2343-2348 ◽  
Author(s):  
E. Bill ◽  
E. L. Bominaar ◽  
X. -Q. Ding ◽  
A. X. Trautwein ◽  
H. Winkler ◽  
...  
Keyword(s):  
Spin Coupling ◽  
Model Systems ◽  
Cation Radicals ◽  
Porphyrin Cation ◽  
Metal Radical

ENDOR Study of the Cation Radicals of Vitamin E Derivatives. Relation between Antioxidant Activity and Molecular Structure

1992 ◽  
Vol 65 (8) ◽  
pp. 2016-2020 ◽  
Author(s):  
Kazuo Mukai ◽  
Yuichi Uemoto ◽  
Masami Fukuhara ◽  
Shin-ichi Nagaoka ◽  
Kazuhiko Ishizu
Keyword(s):  
Molecular Structure ◽  
Antioxidant Activity ◽  
Vitamin E ◽  
Cation Radicals
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