Sulfoxides: Potent Co-Crystal Formers

The design of co-crystals requires knowledge of robust supramolecular synthons. The sulfoxide is a potent hydrogen bond acceptor and has been used as a co-crystal former with a range of NH functional groups, via N−H···OS hydrogen bonds. The NH functional group retains favorable hydrogen bond motifs from its own structure in all cases where this is possible, with the sulfoxide interacting in a discrete, capping fashion in four cases and in a bifurcated, bridging fashion in the three other cases presented here.