A dinitrodiphenyldiquinoline host for selective inclusion of polar guests

The molecular framework of 1 has been used as the starting point for the design of new host molecules that use alternative sensor groups to the halogens employed previously. Addition of phenyl substituents increases the opportunities for pi center dot center dot center dot pi interaction, and consequently, diquinoline 3 was, as expected, a nonhost. However, the further introduction of nitro sensor groups induced selectivity toward the inclusion of polar guest molecules for the first time. Hence the dinitrodiphenyldiquinoline 6 forms 1: 1 inclusion compounds when crystallized from polar solvents such as methanol, N,N- dimethylformamide (DMF), and pyridine. The X-ray crystal structures of these compounds are reported and analyzed in crystal engineering terms.