Solvent-free synthesis and purification of a photoproduct via sublimation of a tetrahalogenated template

Abstract

The solvent-free formation and purification of the photoproduct rctt-tetrakis(4-pyridyl)cyclobutane has been achieved using 1,2-dibromo-4,5-difluorobenzene as the template. Dry vortex grinding yielded the photoreactive co-crystal. During the [2 + 2] cycloaddition reaction, the template readily sublimes resulting in virtually pure photoproduct in a completely solvent-free approach.