Temperature dependence of proton magnetic resonance solvent shifts. 3,5-Dichlorosalicylaldehyde in carbon tetrachloride and benzene

1968 ◽  
Vol 46 (19) ◽  
pp. 3110-3112 ◽  
Author(s):  
G. Kotowycz ◽  
T. Schaefer
Keyword(s):  
Carbon Tetrachloride ◽  
Temperature Dependence ◽  
Proton Magnetic Resonance ◽  
Benzene Solution ◽  
Chemical Shifts ◽  
Relative Temperature ◽  
Proton Shift ◽  
Solvent Shifts ◽  
Solvent Molecules ◽  
Proton Chemical Shifts

The ring proton chemical shifts of 3,5-dichlorosalicylaldehyde as a function of temperature in carbon tetrachloride and benzene solutions indicate that if there is association with solvent molecules in benzene solution, then there is also association with carbon tetrachloride solvent molecules. The aldehydic proton shift shows a much smaller (relative) temperature dependence in the carbon tetrachloride solution.

NMR-spektroskopische Untersuchungen über zwischenmolekulare Wechselwirkungen bei Benzolderivaten und Pyrrol / NMR-Spectroscopic Investigation of the Intermolecular Reactions of Benzene Derivatives and Pyrrole

1969 ◽  
Vol 24 (11) ◽  
pp. 1365-1370 ◽  
Author(s):  
H.-H. Perkampus ◽  
U. Krüger ◽  
W. Krüger
Keyword(s):  
Dipole Moment ◽  
Temperature Dependence ◽  
Aromatic Compounds ◽  
Spectroscopic Investigation ◽  
Chemical Shifts ◽  
Benzene Derivatives ◽  
Intermolecular Reactions ◽  
Proton Chemical Shifts

The proton chemical shifts of aromatic compounds are strongly concentration dependent. Moreever, for molecules with a dipole moment a temperature dependence of the proton chemical shifts is observed. For hemellitone, p-methylanisole, o-chlortoluene, p-chlortoluene, pyrrole and N-methyl-pyrrole the enthalpies of a dipole-dipole association between -0,7 and -1,8 Kcal could be estimated by NMR measurements combined with the temperature dependence in the whole range of the molefraction (0 → 1).

The transmission of polar effects. Part VII. A proton magnetic resonance spectra study of substituted mesitylenes, durenes, anthracenes, and triptycenes

1968 ◽  
Vol 46 (24) ◽  
pp. 3903-3908 ◽  
Author(s):  
Keith Bowden ◽  
J. G. Irving ◽  
M. J. Price
Keyword(s):  
Dielectric Constant ◽  
Free Energy ◽  
Carbon Tetrachloride ◽  
Field Effect ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Linear Free Energy ◽  
Solvent Dependence ◽  
Similar Dependence ◽  
Energy Relations

The chemical shifts of the ring protons in a series of monosubstituted mesitylenes and durenes, and of the 10-protons of a series of 9-substituted triptycenes and anthracenes have been measured in dimethyl sulfoxide, acetone, 2-methoxyethanol, and carbon tetrachloride. The solvent dependence of the substituent chemical shifts has been analyzed by linear free energy relations. The systems all show similar dependence which increases with increasing dielectric constant of the solvent. This does not result from the field effect being transmitted through the medium, but appears to arise from the formation of a hydrogen-bonded interaction between the solvent and the hydrogen of the solute. The substituent chemical shifts appear to arise from contributions from substituent field, resonance, magnetic anisotropy, and solvent effects.

Effect of solvent and anion upon the proton magnetic resonance spectrum of the 1-methylpyridinium ion

1968 ◽  
Vol 46 (17) ◽  
pp. 2787-2791 ◽  
Author(s):  
W. F. Reynolds ◽  
U. R. Priller
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Proton Magnetic Resonance Spectrum ◽  
Concentrated Solutions ◽  
Nonpolar Medium ◽  
Ion Proton ◽  
Acetonitrile Solutions ◽  
Proton Chemical Shifts ◽  
Pyridinium Ion

The proton magnetic resonance spectra of 1-methylpyridinium bromide and iodide have been measured over a range of concentrations in different solvents. It is found that, with the exception of acetonitrile solutions, the infinite dilution chemical shifts are related to solvent dielectric constant. Extrapolated shifts for a nonpolar medium agree with previously calculated chemical shifts for the pyridinium ion. Proton chemical shifts in concentrated solutions are affected by cation–anion interactions. These interactions are interpreted in terms of ion pair formation.

The analysis of the proton magnetic resonance spectra of heteroaromatic systems. V. Diazanaphthalenes

1965 ◽  
Vol 18 (5) ◽  
pp. 707 ◽  
Author(s):  
PJ Black ◽  
ML Heffernan
Keyword(s):  
Carbon Tetrachloride ◽  
Magnetic Resonance ◽  
Long Range ◽  
Iterative Procedure ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Direct Calculation ◽  
Coupling Constants ◽  
Dilute Solutions ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of the four isomeric diazanaphthalenes, quinoxaline, phthalazine, quinazoline, and cinnoline, all as dilute solutions in carbon tetrachloride and acetone, have been investigated at 100 Mc/s. The chemical shifts and coupling constants have been obtained by direct calculation or, where appropriate, by an iterative procedure. Long-range coupling constants between protons separated by five and six bonds have been observed.

Self Association of Folic Acid in Aqueous Solution by Proton Magnetic Resonance

1972 ◽  
Vol 50 (14) ◽  
pp. 2357-2363 ◽  
Author(s):  
Yui-Fai Lam ◽  
George Kotowycz
Keyword(s):  
Aqueous Solution ◽  
Folic Acid ◽  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Disodium Salt ◽  
Intermolecular Association ◽  
Self Association ◽  
Hydrophobic Portion ◽  
Proton Chemical Shifts

Proton magnetic resonance experiments on the disodium salt of folic acid in aqueous solutions (pD 7.1) indicate that the folate ion exists in an unfolded, extended conformation in solution. However, based on a temperature and concentration dependence of the proton chemical shifts, folate ions are involved in intermolecular association consisting of a vertical stacking interaction. A stacking model is proposed for the association with the hydrophilic ends of the molecule alternating in orientation with respect to the hydrophobic portion of the neighboring molecules.

Temperature dependence of chemical shifts of protons in hydrogen bonds. Experimental evidence on an intramolecular hydrogen bond

1968 ◽  
Vol 46 (17) ◽  
pp. 2865-2868 ◽  
Author(s):  
T. Schaefer ◽  
G. Kotowycz
Keyword(s):  
Hydrogen Bond ◽  
Carbon Tetrachloride ◽  
Chemical Shift ◽  
Hydrogen Bonds ◽  
Temperature Dependence ◽  
Intramolecular Hydrogen Bond ◽  
Chemical Shifts ◽  
Hydroxyl Proton ◽  
Intramolecular Hydrogen ◽  
Strong Intramolecular Hydrogen Bond

A temperature dependence of the chemical shift of the hydroxyl proton in the strong intramolecular hydrogen bond in 3,5-dichlorosalicylaldehyde is observed in carbon tetrachloride and benzene-d6 solutions. Its magnitude of 0.25 to 0.30 × 10−2 p.p.m. per ° C over a range of 100 °C is in agreement with the model described by Muller and Reiter (1).

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