Photochemically induced valence bond tautomerism and dimerisation of 3-oxido-1-phenylpyridinium
Abstract
Irradiation of the title compound (1a) yields one of the expected dimers (4) together with the valence bond isomer (5) and two isomeric products (10) and (11) of thermal cycloaddition of the valence bond tautomer (5) to the starting betaine (1a).