Effects of p-substituents on the conformation of acetophenone

Abstract

Experimental dipole moments and infinite-dilution molar Kerr constants are reported for six p-substituted acetophenones (CH₃COC₆H₄X; X = Me, Bu^t, NO₂, CN, F, Br) as solutes in carbon tetrachloride at 298 K. Analysis of these results and reconsideration of previously reported data for acetophenone and p-chloroacetophenone yields the dihedral angle, Φ, between the planes of the carbonyl and aryl groups in the effective conformation of each molecule (X = H, Φ = 0°; Me, 0°; Bu^t, 10±10°; NO₂, 20±15°; NO₂, 20±20°; F, 27±5°; Cl, 32±5°; Br, 30±10°).