The application of the Hammett equation to 13C N.M.R. spectrometry. IV. Solvent effects

1982 ◽  
Vol 35 (1) ◽  
pp. 21 ◽  
Author(s):  
DAR Happer
Keyword(s):  
Carbon Tetrachloride ◽  
Dimethyl Sulfoxide ◽  
Solvent Effects ◽  
Aqueous Ethanol ◽  
Chemical Shifts ◽  
Hammett Equation ◽  
Solvent Dependence ◽  
Ethanol Ethanol ◽  
Vinyl Group

The chemical shifts for Cβ of the vinyl group of styrene and 16 of its meta-or para-substituted derivatives have been measured in seven solvents: 75% aqueous ethanol, ethanol, dimethyl sulfoxide, acetone, deuterochloroform, carbon tetrachloride and benzene. Attempts have been made to correlate the data by means of the Hammett equation, discrepancies being discussed in terms of solvent dependence of σ and p.

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.

Chemical and Physical Effects upon Carbonyl Stretching Frequencies: Ketones

1989 ◽  
Vol 43 (6) ◽  
pp. 981-983 ◽  
Author(s):  
R. A. Nyquist ◽  
V. Chrzan ◽  
J. Houck
Keyword(s):  
Carbon Tetrachloride ◽  
Dimethyl Sulfoxide ◽  
Solvent Effects ◽  
Mole Percent ◽  
Resonance Effects ◽  
Carbon Tetrachloride Solution ◽  
Dimethyl Sulfoxide Solution ◽  
Physical Effects

The carbonyl stretching frequencies for a series of ketones occur at a lower frequency in dimethyl sulfoxide solution than in carbon tetrachloride solution, and occur at intermediate frequencies depending upon the mole percent ratio (CH3)2SO/CCl4. Ketones of form (CH3)2C=O, φ(C=O)CH3, and (φ)2C=O exhibit carbonyl stretching frequencies which are affected in the same manner by solvent effects. In general, inductive and resonance effects play an important role in determining the unperturbed carbonyl stretching frequencies of ketones.

1H, 13C and 15N NMR Spectra of Coupling Products of Benzenediazonium Salts with Aliphatic Nitro Compounds and Study of Their E/Z Isomerism

1996 ◽  
Vol 61 (4) ◽  
pp. 589-596 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Dimethyl Sulfoxide ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Nitro Compounds ◽  
Coupling Constants ◽  
15N Nmr ◽  
Geometrical Isomers ◽  
Sodium Salts ◽  
Aliphatic Nitro Compounds ◽  
Tautomeric Forms

The 1H, 13C and 15N NMR spectra have been measured of coupling products of benzenediazonium salts with nitromethane, nitroethane, 1-nitropropane, 2-nitroethanol and of their sodium salts, and the chemical shifts have been unambiguously assigned. The coupling products have been found to exist only in their hydrazone tautomeric forms. Stereospecific behaviour of the coupling constants 2J(15N,1H) and 2J(15N,13C) in the 15N isotopomers and NOESY have been used to differentiate between the E and Z geometrical isomers. The above-mentioned compounds exist as Z isomers in deuteriochloroform and predominantly (>95%) as E isomers in dimethyl sulfoxide, while the sodium salts are present only as E isomers in dimethyl sulfoxide.

Solvent Effects on Oxygen-17 Chemical Shifts in Methyl Formate: Linear Solvation Shift Relationships

2001 ◽  
Vol 148 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Dora G. de Kowalewski ◽  
Valdemar J. Kowalewski ◽  
Ruben H. Contreras ◽  
Ernesto Dı́ez ◽  
Jorge Casanueva ◽  
...  
Keyword(s):  
Solvent Effects ◽  
Methyl Formate ◽  
Chemical Shifts ◽  
Linear Solvation

Reversal of order of chemical shifts. Differential solvent effects in the hydrogen shifts of toluene,m-xylene ando-xylene as determined by 320 MHz tritium NMR spectroscopy

1984 ◽  
Vol 22 (10) ◽  
pp. 665-667 ◽  
Author(s):  
Mervyn A. Long ◽  
John K. Saunders ◽  
Philip G. Williams ◽  
Allan L. Odell ◽  
R. Wayne Martin
Keyword(s):  
Nmr Spectroscopy ◽  
Solvent Effects ◽  
Chemical Shifts ◽  
Tritium Nmr ◽  
Hydrogen Shifts

Circular dichroism spectra of tetraamminecobalt(III) complexes of amino alcohols

1978 ◽  
Vol 31 (11) ◽  
pp. 2399 ◽  
Author(s):  
CJ Hawkins ◽  
GA Lawrance ◽  
JA Palmer
Keyword(s):  
Circular Dichroism ◽  
Chemical Shift ◽  
Chemical Shifts ◽  
Amino Alcohols ◽  
Circular Dichroism Spectra ◽  
Chemical Shift Difference ◽  
Solvent Dependence ◽  
Cotton Effects ◽  
Circular Dichroïsm ◽  
Chiral Amino Alcohols

The circular dichroism spectra are reported for tetraamminecobalt(III) complexes with the chiral amino alcohols 2-aminopropan-1-ol, 2- aminobutan-1-ol, 1-aminopropan-2-ol, 2-amino-1-phenyl-ethanol, ψ- ephedrine and ephedrine with the alcohol groups protonated (OH) and deprotonated (O-). The solvent dependence of the chemical shifts of the NH protons was investigated to determine the effects of stereoselective solvation on the circular dichroism, but, in contrast to some other related systems, the chemical shift difference between the two NH2 protons was relatively insensitive to solvent. Consistent with this, the circular dichroism spectra of the tetraphenylborate salts of the deprotonated complexes were found not to be markedly dependent on solvent. Tetraammine-{(-)-ψ-ephedrine)cobalt(III) and tetraammine{(-)- ephedrine}cobalt(III) were found to have the same signs of Cotton effects for the various d-d transitions, whereas bis{(-)-ψ- ephedrine}copper(II) and bis{(-)-ephedrine}copper(II) had opposite signs. This has been explained in terms of different conformer populations in the cobalt(III) and copper(II) systems.

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