Nature of the 190-nm Transition in Carbonyls: CD Measurments of Camphor Using Synchrotron Radiation

The CD of the 190-nm transition of ketones was recently the subject of an extensive study. The measurements extended the wavelength region to 185 nm and solvents such as hexane, acetonitrile, and trifluoroethanol were used. The second transition in simple ketones was assigned as the n → 3s Rydberg. This assignment was based on the behavior of this transition under increasing pressure of a perturbing gas or in solution where vibronic structure is lost and substantial blue shifts are observed. Fluorine-containing solvents are especially known as strong shifters.