Molecular polarisability. Conformations of α- and β-ionones as solutes in benzene

Abstract

Dipole moments, molar Kerr constants, refractivities, etc., are reported for α- and β-ionones. The proton magnetic resonance spectra of the ionones confirm the trans-configuration of the carbon–carbon double bond in the side-chain. The cyclohexene ring in α-ionone has been shown to be rigid and in a “half-chair” form. Comparisons of values of ∞(_mK₂) from experiment with those calculated from bond polarisability data indicate certain preferred conformations for these molecules. Details of the calculation of molecular polarisability tensors using a vector analytical approach are given, and the isomer contents of commercial α- and β-ionones estimated by way of the Kerr effect.