Intramolecular interactions. XXIV. Conformations of benzylic compounds. Molecular optical anisotropies, dipole moments, and Kerr constants

1975 ◽  
Vol 79 (18) ◽  
pp. 1962-1966 ◽  
Author(s):  
Michel Camail ◽  
Alain Proutiere ◽  
Patrick Verlaque
Keyword(s):  
Dipole Moments ◽  
Intramolecular Interactions ◽  
Kerr Constants

Dipole moments and Kerr constants of dibenzoates of some diols with different numbers of methylene units as model compounds for polyesters

1990 ◽  
Vol 23 (4) ◽  
pp. 1139-1144 ◽  
Author(s):  
Francisco Mendicuti ◽  
Maria M. Rodrigo ◽  
Maria P. Tarazona ◽  
Enrique Saiz
Keyword(s):  
Dipole Moments ◽  
Model Compounds ◽  
Kerr Constants

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.

Probing Intramolecular Interaction of Stereoisomers Using Computational Spectroscopy

2020 ◽  
Vol 73 (8) ◽  
pp. 813
Author(s):  
Feng Wang ◽  
Shawkat Islam ◽  
Frederick Backler
Keyword(s):  
Hydrogen Bonding ◽  
Binding Energy ◽  
Gas Phase ◽  
Intramolecular Interaction ◽  
Dipole Moments ◽  
Energy Difference ◽  
Binding Energies ◽  
Intramolecular Interactions ◽  
Computational Spectroscopy ◽  
Ionic States

Several model stereoisomers such as ferrocene (Fc), methoxyphenol, and furfural conformers are discussed. It was discovered that the Fc IR spectroscopic band(s) below 500cm−1 serve as fingerprints for eclipsed (splitting 17 (471–488)cm−1) and staggered Fc (splitting is ~2 (459–461)cm−1) in the gas phase. It is revealed that in the gas phase the dominance of the eclipsed Fc (D5h) at very low temperatures changes to a mixture of both eclipsed and staggered Fc when the temperature increases. However, in solvents such as CCl4, eclipsed Fc dominates at room temperature (300K) due to the additional solvation energy. Intramolecular interactions of organic model compounds such as methoxyphenols (guaiacol (GUA) and mequinol (MEQ)) and furfural, ionization energies such as the carbon 1s (core C1s), as well as valence binding energy spectra serve this purpose well. Hydrogen bonding alters the C1s binding energies of the methoxy carbon (C(7)) of anti-syn and anti-gauche conformers of GUA to 292.65 and 291.91eV, respectively. The trans and cis MEQ conformers, on the other hand, are nearly energy degenerate, whereas their dipole moments are significantly different: 2.66 Debye for cis and 0.63 Debye for trans-MEQ. Moreover, it is found that rotation around the Cring–OH and the Cring–OCH3 bonds differ in energy barrier height by ~0.50 kcal⋅mol−1. The Dyson orbital momentum profiles of the most different ionic states, 25a′ (0.35eV) and 3a′ (−0.33eV), between cis and trans-MEQ in outer valence space (which is measurable using electron momentum spectroscopy (EMS)), exhibit quantitative differences. Finally, the molecular switch from trans and cis-furfural engages with a small energy difference of 0.74 kcal mol−1, however, at the calculated C(3)(–H⋅⋅⋅O=C) site the C1s binding energy difference is 0.105eV (2.42 kcal mol−1) and the NMR chemical shift of the same carbon site is also significant; 7.58ppm from cis-furfural without hydrogen bonding.

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