The theoretical conformational analysis of some bridged aromatic compounds: diphenyl ether, diphenylmethane, benzophenone and diphenyl sulphide

Structural aspects in polymers: interconnections between conformational parameters of the polymers with their physical properties

“…Here the u angle determines the conformation of that bond. [17,18] that the conformation of such bonds is mostly trans, i.e., the u angle equals 0°. For the CO O bond, the conformational energy minimum corresponds to trans-conformation ±6°, and transition into cis-conformation requires energy of 5-10 kcal/mol [19,20].…”

Ab initio calculations of phenylene ring motions in polyphenylene oxide

“…There has been considerable controversy in the literature concerning the favored geometry for diphenyl ether, with different scientific evidence supporting the Morino and skewed forms. Theoretical conformational studies on this molecule have been attempted by Zubkov, Birshtein, and Milevskaya [16], by Galasso, De Alti, and Bigotto [7], and by Smeyers and Hernandez-Laguna [ 171 in order to identify the favored conformation and determine the energy barrier for phenyl group rotation. Zubkov et al [16] performed classic and semiempirical calculations of the various conformations; their results were quite indecisive.…”

“…Theoretical conformational studies on this molecule have been attempted by Zubkov, Birshtein, and Milevskaya [16], by Galasso, De Alti, and Bigotto [7], and by Smeyers and Hernandez-Laguna [ 171 in order to identify the favored conformation and determine the energy barrier for phenyl group rotation. Zubkov et al [16] performed classic and semiempirical calculations of the various conformations; their results were quite indecisive. EHT and CND0/2 calculations favor the Morino structure, MrND0/2 favored structure A, and the classic calculations using Lennard-Jones (12,6) potentials plus the torsional term KO,, = V2(1 -cos 241) + V*(1 -cos 242) predicted the skewed form (X) to be lowest in energy.…”

Anisotropie optique d’hétérocycles soufrés et oxygénés

“…calculée en fonction de l'angle de torsion a est représentée sur la figure 1 relativement peu traitée (tableau VI); des deux conforma tions compatibles avec l'a.o.m. expérimentale la prem ière recoupe le résultat fourni par la diffraction des rayons-X (47), la seconde rejoint la conclusion d'une étude théorique récente (48).…”