142167-52-0Relevant articles and documents
CONFORMATIONAL AND ELECTRONIC INTERACTION STUDIES OF α-SUBSTITUTED CARBONYL COMPOUNDS. XI. ω-(p-PHENYLTHIO)-p-SUBSTITUTED ACETOPHENONES
Olivato, Paulo R.,Guerrero, Sandra A.
, p. 207 - 222 (2007/10/02)
The analysis of the νCO bands in the I.R. spectra of ω-(p-phenylthio)-p-substituted acetophenones indicates the presence of cis/gauche rotational isomerism.The decreasing cis/gauche ratio on going from electron-attracting to electron-donating substituents at the phenylthio group in each p-substituted acetophenone series is discussed in terms of the ?*CO/?C-S hyperconjugative interaction in the gauche rotamers.The carbonyl cis shifts (Δνc) of the title compounds are interpreted as due to an interplay of Field (F) and Inductive (I) Effects.The carbonyl gauche shifts (Δνg) trend in the whole series has been ascribed to the variation of the extension of the ?*CO/?C-S hyperconjugative interaction.The lower Non-Additivity Effect (NAE) of the methylene carbon of the title compounds in relation to the corresponding ω-bromo and ω-iodo acetophenones together with the lowest NAE of the methylene carbon for the ω-(p-nitrophenylthio)-p-nitroacetophenone (3) suggests the simultaneous occurrence of the ?*CO/?C-S and ?CO/?*C-S orbital interactions.The U.V. spectra of the ω-thiosubstituted acetophenones display a n -> ?*CO band which is bathochromically shifted in relation to the corresponding acetophenones except for compound (3) where this band is hypsochromically shifted.This behavior has been ascribed mainly to the ?*CO/?*C-S hyperconjugative interaction in the excited state.Key words: Conformational studies; electronic interactions; I.R. spectroscopy; 13C NMR spectroscopy; U.V. spectroscopy; ω-(p-phenylthio)-p-substituted acetophenones.
