The structural convergence of two aromatic inclusion host families

The Weber multi-ring aryl hydrocarbons 1–4, dihalo diheteroaryl 6,8, and tetrahalo aryl 10,12 compounds are examples of host molecules from well-known families of lattice inclusion systems. Despite these three systems having a number of features in common, no attempt has been made previously to establish their inter-relationship. In this work, the diheteroaryl ring system of 5 has been substituted with two and four pendant phenyl groups to give the non-halogenated compounds 15 and 17, respectively. In common with typical unsubstituted diheteroaryl compounds (such as 5 and 7), compound 15 shows no host properties. On the other hand, 17 can include several different guests and therefore its behaviour represents a cross-over into the Weber system. Crystal engineering aspects of the X-ray structures of 15, (17)·(chloroform) and (17)·(toluene) are analysed in this light.