The magnetic dipole character and the rotatory power of the 3000 Å carbonyl absorption

Publisher Website
Google Scholar
Abstract
A new experimental criterion is advanced for magnetic dipole allowed transitions of electrons in polyatomic molecules, based upon the relative band areas of the circular dichroism and of the corresponding unpolarized absorption given by the chromophores of optically active compounds. The 3000 Å carbonyl absorption is shown to be magnetic dipole allowed, although most of the absorption intensity derives from a vibrationally induced or stereochemically determined charge transfer contribution, which has an electric dipole moment with a component directed parallel to the carbonyl bond axis in optically active ketones. The known features of the formaldehyde 3000 Å absorption are interpreted in terms of a magnetic dipole transition moment orientated along the carbonyl bond, and a charge transfer electric dipole moment directed perpendicular to that bond in the plane of the molecule, induced by the methylene out-of-plane bending vibration.

This publication has 47 references indexed in Scilit: