A Study of the Interactions Between the Double Bonds in Unsaturated Ketones

The interactions between C=C and C=O double bonds in several unsaturated ketones have been studied by comparing MIND0/2 caloulations wiith ionisation potentials determined by photoelectron spectroscopy (PES). With one exception (norbornadienone) the direct through-space interactions in conjugated .ketones appear to be negligible, the double bonds couple hyperoonjugatively via the intervening a bonds. This kind of approach should prove useful for studying other long range interactions