Carbonyl n–π* absorption enhancement in β-phenylketones: the molecular geometry of the 6-benzyl-2,6-dimethylcyclohexa-2,4-dienone Diels–Alder dimer and its photocage product

Abstract

The molecular structures of the 6-benzyl-2,6-dimethylcyclohexa-2,4-dienone Diels–Alder dimer and its intramolecular photocycloaddition product have been determined by crystallographic methods. The enhancement of then n–π* absorption in the u.v. spectrum of the photoproduct is discussed in terms of geometrically facilitated orbital interactions between the carbonyl group and its β-phenyl substituent.