Stereospecific and quantitative photodimerisation of terminal olefins in the solid state

Reaction of 4-vinylpyridine with AgClO(3) yields a crystalline solid that supports a stereospecific and quantitative [2 + 2] photodimerisation of two terminal olefins. Structural dynamics of the CH=CH(2) group, nature of the counterion, and extended packing influence the photoreactivity.