The effect of chlorine substitution on the inclusion properties of a diquinoline host molecule

The chloro-substituted diquinoline compounds 7 and 8 have been synthesised as part of our continuing search for new host molecules. As intended,the latter forms lattice inclusion compounds with a range of molecules, and here the X-ray structures of (8)4.(benzene)5 and (8).(toluene) are describes. Host 8 exhibits entirely different inclusion behaviour compared to its parent non-chlorinated analogue 2. Edge-edge double C-H...N synthons, normally ubiquitous in inclusion structures formed by members of this diquinoline host family, vanish when 8 is used. Instead there is increased dependence on halogen-halogen and aryl-aryl interactions. Despite the similarity of the guests, the structures of the two inclusion compounds are very different. Crystal engineering analysis reveals, however, that the supramolecular synthons present in the two cases are very similar.