CIRCULAR-DICHROISM OF ORIENTED MOLECULES - ELECTRIC-DIPOLE MAGNETIC DIPOLE AND ELECTRIC-DIPOLE ELECTRIC QUADRUPOLE CONTRIBUTION FOR CHOLEST-4-EN-3-ONE

Three independent molecular quantities DELTAepsilon(II)* have been determined for 2,2,4,6,6-d5-cholest-4-en-3-one (1) by the circular dichroism of isotropic (CD) and anisotropic (ACD) samples using order parameters evaluated from H-2 NMR spectra. The orientation axis depends on temperature which may originate from a conformational change of 1. A refined analysis of the ACD measurements is given and applied to 1 because all coordinates of the order tensor are known. The order of the molecules as calculated from H-2 NMR spectra is higher than that obtained by UV and IR spectroscopy. The estimated electric dipole/electric quadrupole contribution to the ACD is in the order of magnitude of the electric dipole/magnetic dipole contribution.