Conformations of some 4- and 4,4'-Di-substituted benzophenones

1980 ◽  
Vol 33 (10) ◽  
pp. 2181 ◽  
Author(s):  
PH Gore ◽  
IG John ◽  
GLD Ritchie
Keyword(s):  
Carbon Tetrachloride ◽  
Dipole Moments ◽  
Steric Effects ◽  
Minor Role ◽  
Conformational Preferences ◽  
A Minor ◽  
Kerr Constants

Experimental dipole moments and molar Kerr constants are reported for eight 4- and 4,4?-halogeno- and -methyl-benzophenones as solutes in carbon tetrachloride at 298 K. Analysis of the results elucidates the conformational preferences of these molecules and suggests that steric effects are of predominant importance, whereas the additional conjugative interactions provided by the substituents apparently play only a minor role.

Molecular polarizability. The dipole moments, molar Kerr constants, and conformations of some chloroformic esters

1969 ◽  
Vol 22 (8) ◽  
pp. 1599 ◽  
Author(s):  
MJ Aroney ◽  
FFvre RJW Le ◽  
RK Pierens ◽  
HLK The
Keyword(s):  
Experimental Data ◽  
Carbon Tetrachloride ◽  
Dipole Moments ◽  
Molecular Polarizability ◽  
Methyl Ethyl ◽  
Conformational Preferences ◽  
Kerr Constants

Dipole moments and molar Kerr constants are reported for methyl, ethyl, and phenyl chloroformates in carbon tetrachloride and in benzene. The experimental data are analysed to provide information on the conformational preferences of the solutes in the ?inert? CCl4 environment and on solute-solvent associations in benzene.

Dipole moments, Kerr constants and solution-state conformations of di(pyridin-4-yl), di(pyridin-3-yl) and di(pyridin-2-yl) ketone

1980 ◽  
Vol 33 (12) ◽  
pp. 2597 ◽  
Author(s):  
PH Gore ◽  
IG John ◽  
RK Pierens ◽  
GLD Ritchie
Keyword(s):  
Carbon Tetrachloride ◽  
Dipole Moments ◽  
Strong Preference ◽  
Trans Conformation ◽  
Solution State ◽  
Kerr Constants

Experimental dipole moments and molar Kerr constants are reported and analysed for di(pyridin-4-yl), di(pyridin-3-yl) and di(pyridin-2-yl) ketone as solutes in carbon tetrachloride or cyclohexane at 298 K. The preferred conformation of di(pyridin-4-yl) ketone is found to be very similar to those previously deduced for benzophenone and several 4,4'- disubstituted benzophenones. For di(pyridin-3-yl) and di(pyridin-2-yl) ketone three analogous conrotatory structures having different relative dispositions of the nitrogen atoms are considered. In the case of di(pyridin-3-yl) ketone the cis-trans and trans-trans arrangements are approximately equally abundant, but for di(pyridin-2-yl) ketone there is a strong preference for the trans-trans conformation.

The conformations of some organic carbonates

1981 ◽  
Vol 34 (2) ◽  
pp. 349 ◽  
Author(s):  
LHL Chia ◽  
KJ Kwan ◽  
HH Huang
Keyword(s):  
Experimental Data ◽  
Carbon Tetrachloride ◽  
Electric Dipole ◽  
Dimethyl Carbonate ◽  
Dipole Moments ◽  
Diphenyl Carbonate ◽  
Diethyl Carbonate ◽  
Electric Dipole Moments ◽  
Organic Carbonates ◽  
Kerr Constants

Electric dipole moments and molar Kerr constants are reported for seven organic carbonates (dimethyl carbonate, diethyl carbonate, vinylene carbonate, diphenyl carbonate, di-p-tolyl carbonate, di-o- tolyl carbonate and t-butyl phenyl carbonate) examined as solutes in carbon tetrachloride at 25�. The experimental data are analysed to provide information on the probable solution-state conformations.

Conformations of vinyl formate and vinyl acetate

1976 ◽  
Vol 29 (3) ◽  
pp. 581 ◽  
Author(s):  
MJ Aroney ◽  
EAW Bruce ◽  
IG John ◽  
L Radom ◽  
GLD Ritchie
Keyword(s):  
Carbon Tetrachloride ◽  
Ab Initio ◽  
Gas Phase ◽  
Vinyl Acetate ◽  
Molecular Orbital ◽  
Dipole Moments ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Theoretical Predictions ◽  
Kerr Constants

Ab initio molecular orbital theory has been used to deduce the preferred gas-phase conformations of vinyl formate and vinyl acetate. In addition, experimental dipole moments (1030μ/Cm) and molar Kerr constants (1027mK/m5 V-2 mol-1) at 25�C are reported for both molecules as solutes in carbon tetrachloride: vinyl formate (5.07, + 48.1) and vinyl acetate (5.70, + 3.8). The preferred solution-state conformations indicated by the analysis of these results are shown to be consistent with the theoretical predictions.

The Conformational Equilibrium of 1,2,3-Tribromopropane in Solution

1973 ◽  
Vol 51 (4) ◽  
pp. 565-572 ◽  
Author(s):  
L. Ernst ◽  
T. Schaefer
Keyword(s):  
Conformational Equilibrium ◽  
Dipole Moments ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Minor Role ◽  
Nonpolar Solvents ◽  
Spin Coupling Constants ◽  
A Minor ◽  
Spin Spin Coupling ◽  
Rule Out

The p.m.r. spectra of dilute solutions of 1,2,3-tribromopropane in carbon tetrachloride, acetonitrile, and dimethylsulfoxide as well as of the neat compound are examined. From the three- and four-bond spin–spin coupling constants and from a comparison between observed and calculated dipole moments it is concluded that in nonpolar solvents the title compound exists preferably in the enantiomeric conformations a and i. In polar solvents other rotamers contribute to the equilibrium but still seem to play only a minor role. Semiempirical calculations of conformational energies rule out contributions to the conformational equilibrium from rotamers having (1:3) bromine–bromine interactions, but otherwise are only in moderate agreement with experiment.

Dipole Moments, Kerr Constants and Solute Conformations of the Aryl Methyl Sulfones p-XC6H4S(02)CH3 (X = H, Cl, BR or NO2)

1987 ◽  
Vol 40 (3) ◽  
pp. 619 ◽  
Author(s):  
MJ Aroney ◽  
RJW LeFevre ◽  
RK Pierens ◽  
HJ Stootman ◽  
MGM Yong
Keyword(s):  
Experimental Data ◽  
Carbon Tetrachloride ◽  
Infinite Dilution ◽  
Dipole Moments ◽  
Solution State ◽  
Dimethyl Sulfone ◽  
Kerr Constants ◽  
Aryl Methyl

Measurements are reported of the infinite-dilution dipole moments and molar Kerr constants of dimethyl sulfone and of the four aryl methyl sulfones p-XC6H4S(02)CH3 (X = H, Cl, Br or NO2) dissolved in carbon tetrachloride or dioxan at 298 K and under light of 589 nm. The experimental data are analysed to obtain information on the solution-state conformations in relation to steric and electromeric effects operative between the aryl and methanesulfonyl groups.

Conformations of Di(4-pyridyl) disulphide and Di(2-pyridyl) disulphide

1973 ◽  
Vol 26 (8) ◽  
pp. 1785 ◽  
Author(s):  
CL Cheng ◽  
GLD Ritchie
Keyword(s):  
Carbon Tetrachloride ◽  
Dipole Moments ◽  
Analysis Of Results ◽  
Kerr Constants

Experimental dipole moments and molar Kerr constants at 25�C are reported for di(4-pyridyl) disulphide (1.68 D, + 11 x 10-12 e.s.u. mol-1) and di(2-pyridyl) disulphide (3.95 D, -240x10-12 e.s.u. mol-1) as solutes in carbon tetrachloride. Analysis of results yields information concerning the preferred conformations of these molecules.

The molar Kerr constants, apparent dipole moments, etc., of alkyl nitrites as solutes

1968 ◽  
Vol 21 (8) ◽  
pp. 1965
Author(s):  
FRJW Le ◽  
RK Pierens ◽  
DV Radford ◽  
KD Steel
Keyword(s):  
Carbon Tetrachloride ◽  
Dipole Moments ◽  
Alkyl Nitrites ◽  
Dissolved Species ◽  
Kerr Constants

The apparent dipole moments of ten, and the apparent molar Kerr constants of seven, alkyl nitrites as solutes in carbon tetrachloride at 25� are recorded and discussed in terms of assumptions that the dissolved species are either (a) mixtures of two planar forms in which the R-O and K=O bonds have an s-cis : s-trans relationship, or (b) mixtures of many non-planar rotamers, definable by angles of twist 4 between the planes containing the R-O and S=O units. On basis (b) the observed properties are average values, theoretically predictable only when potential energies as functions of � become known. "Effective" conformations for MeO-N=O and Me3CO-N=O having � values of 98� and 146.5� can be inferred from the ∞(mK2) values found for these esters.

The Conformations as Solutes of Diethyl Maleate, Fumarate, and Azodiformate

1962 ◽  
Vol 15 (4) ◽  
pp. 703 ◽  
Author(s):  
RS Armstrong ◽  
MJ Aroney ◽  
RJW Le Fevre
Keyword(s):  
Carbon Tetrachloride ◽  
Dipole Moments ◽  
Diethyl Maleate ◽  
C And N ◽  
Kerr Constants ◽  
Qualitative Discussion

Dipole moments and molar Kerr constants, previously recorded by Le F�vre, Le F�vre, and Oh (1957) with only a qualitative discussion pending availability of information on the anisotropic polarizabilities of the C=C and N=N bonds, are here used to indicate the apparent conformations of diethyl maleate, diethyl fumarate, and diethyl azodiformate as solutes in carbon tetrachloride.

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