Correlation of Proton Magnetic Resonance Shifts with Group Dipole Moments in Substituted Ethylenes

1961 ◽  
Vol 34 (2) ◽  
pp. 700-701 ◽  
Author(s):  
G. S. Reddy ◽  
C. E. Boozer ◽  
J. H. Goldstein
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Dipole Moments

The Variable Electronegativity Method. VI. Azulene

1960 ◽  
Vol 13 (1) ◽  
pp. 38 ◽  
Author(s):  
RD Brown ◽  
ML Heffernan
Keyword(s):  
Experimental Data ◽  
Magnetic Resonance ◽  
Carbon Atom ◽  
Electron Density ◽  
Proton Magnetic Resonance ◽  
Resonance Spectrum ◽  
Dipole Moments ◽  
Proton Magnetic Resonance Spectrum ◽  
Bond Orders ◽  
Electron Distributions

Results of a variable-electronegativity SCF treatment of azulene, using the method used in previous VESCF studies, are reported. A slightly more elaborate method in which non-neighbour core resonance integrals are included has also been used. The π-electron distributions obtained by these methods correspond to dipole moments of 1.85 and 1.33 D respectively, the experimental value being about 1 D. The calculated bond orders accord with the rather incomplete experimental data on bond lengths. The π-electron densities account for the relative chemical reactivities of the azulene positions. The ionization potentials and proton magnetic resonance spectrum of azulene are also briefly considered. The concept of electronegativities of conjugated atoms in non-alternant systems is discussed in some detail on the basis of the VESCF results. It is shown that the assumption that the electronegativity of a carbon atom depends only on its π-electron density is an oversimplification for non-alternant systems.

Acyl derivatives of Hydroxylamine. XIII. Configuration and conformation of hydroxamic acid derivatives containing sulfur

1968 ◽  
Vol 46 (11) ◽  
pp. 1873-1880 ◽  
Author(s):  
O. Exner ◽  
M. H. Benn ◽  
Frances Willis
Keyword(s):  
Magnetic Resonance ◽  
Hydroxamic Acid ◽  
Proton Magnetic Resonance ◽  
Dipole Moments ◽  
Electronic Nature ◽  
Graphical Comparison ◽  
Derivatives Of ◽  
Configuration And Conformation ◽  
Acyl Derivatives ◽  
Hydroxamic Acid Derivatives

The configurations and conformations of S-methyl benzothiohydroxamic acid (3) and its S-oxo and S,S-dioxo derivatives (5) and (7) were established by means of a graphical comparison of their dipole moments with those of the corresponding p-nitro compounds.The proton magnetic resonance and infrared spectra of these compounds were also studied.It is concluded that the relative stability of stereoisomers in the series of compounds C6H5C(NOH)X seems to depend more on the electronic nature of the group X than on its steric requirements.

Nuclear magnetic resonance spectra of the epihalohydrins: II. Spectral analyses and structural correlations for all the epihalohydrins

1970 ◽  
Vol 48 (7) ◽  
pp. 1046-1053 ◽  
Author(s):  
C. J. Macdonald ◽  
W. F. Reynolds
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Long Range ◽  
Propylene Oxide ◽  
Proton Magnetic Resonance ◽  
Dipole Moments ◽  
Coupling Constants ◽  
Vicinal Coupling Constants ◽  
Nuclear Magnetic Resonance Spectra ◽  
Magnetic Resonance Spectra

Complete analyses of the proton magnetic resonance spectra of propylene oxide, epifluorohydrin, epibromohydrin, and epiiodohydrin shows that in all cases the cisoid coupling constants over four bonds are negative, and the transoid coupling constants positive. Dipole moments, together with the vicinal coupling constants of the CH—CH2X moiety, are used to establish the probable conformations for all the epihalohydrins. Conformational factors appear to obscure any possible relationship between substituent electronegativity and long-range coupling constants.

Conformational Studies of Substituted Trimethylene Sulfites by Proton Magnetic Resonance

1972 ◽  
Vol 50 (4) ◽  
pp. 521-527 ◽  
Author(s):  
Gordon Wood ◽  
G. W. Buchanan ◽  
M. H. Miskow
Keyword(s):  
Dipole Moment ◽  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Dipole Moments ◽  
Shift Reagent ◽  
Coupling Constants ◽  
Considerable Degree ◽  
Conformational Studies ◽  
Alkyl Derivatives

Proton n.m.r. chemical shifts and coupling constants are reported for trimethylene sulfite and 10 alkyl derivatives in CCl4. Data are discussed in terms of possible chair and non-chair conformations and results are compared with those from dipole moment studies. The shift reagent Eu(dpm)3 is used to aid configurational assignments. Conclusions from n.m.r. and dipole moments are consistent and indicate that several of the sulfites exist to a considerable degree in non-chair conformations.

Charge distribution in substituted cyclopentadienyl–manganese–tricarbonyl compounds

1967 ◽  
Vol 45 (2) ◽  
pp. 161-166 ◽  
Author(s):  
C. Barbeau
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Central Atom ◽  
Dipole Moments ◽  
Phenyl Group ◽  
Small Extent ◽  
Photochemical Synthesis ◽  
Triphenyl Phosphine ◽  
Donor Acceptor ◽  
Manganese Tricarbonyl

Photochemical synthesis of mono- and bi-substituted cyclopentadienyl–manganese–tricarbonyl compounds with triphenyl-phosphine, arsine, stibine, and bismuth is reported. The infrared absorption and proton magnetic resonance spectra are discussed in relation to the distribution of negative charges among the ligands. The dipole moments were measured and the partial dipole moments for the group manganese–triphenyl compound in these derivatives are calculated and discussed.It is shown that the distribution of negative charges occurs principally between the CO and phenyl ligands and that the donor–acceptor behavior of the phenyl ligands depends mainly on the phenyl group and to a very small extent on the central atom.

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