Cotton-Mouton and Kerr constants of twelve non-dipolar tri- and hexa-substituted benzenes

Abstract

Measurements of the infinite-dilution molar Cotton-Mouton and Kerr constants of 12 non-dipolar 1,3,5-tri- and hexa-substituted benzenes as solutes in carbon tetrachloride at 298 K are reported. Some of the experimental results are in notable disagreement with earlier determinations made on equipment of much lower sensitivity. Although the magnetic anisotropies derived for the tri-substituted benzenes are concordant with other observed or predicted values, those for the hexa-substituted benzenes are generally very much larger than expected. It is suggested, in explanation, that relatively large and strongly anisotropic atomic polarizabilities may cause the ratio of the static to the high-frequency polarizability anisotropy to be considerably smaller in the hexa-substituted benzenes than in benzene; in addition, there may be significant temperature independent contributions to the magnetic birefringences of these molecules.