665. Molecular polarisability. A study of internal rotation in the benzyl halides and related molecules from measurements of molar Kerr constants and dipole moments

Molar Kerr constants and apparent dipole moments are recorded for benzyl chloride, benzyl bromide, benzyl iodide, 1-chloromethylnaphthalene, 4-chlorobenzyl chloride, 4-bromobenzyl bromide, and benzyl cyanide as solutes in carbon tetrachloride at 25°. The dependence of the molar Kerr constants on molecular conformation is considered, and the results discussed in relation to internal rotation in the molecules. For the first four compounds, the potential-energy function governing internal rotation is estimated from van der Waals interaction data, and average molar Kerr constants calculated therefrom.