INVESTIGATIONS INTO THE ROBUSTNESS OF SECONDARY AND TERTIARY ARCHITECTURE OF HYDROGEN-BONDED CRYSTALLINE TAPES

Five crystal structures of hydrogen-bonded complexes (N-(p-iodophenyl)-N'-(p-cyanophenyl)-melamine.barbital, N,N'-diphenylmelamine-5,5-dimethylbarbituric acid, 2-amino-4-((m-bromophenyl)amino)-6-chloro-1,3,5-triazine-barbital, melamine-5,5-dibromobarbituric acid, and melamine-barbituric acid) are presented. These particular components represent perturbations on the molecules that were previously used to construct crystallographic hydrogen-bonded tapes (Zerkowski, J. A.; MacDonald, J. C.; Seto, C. T.; Wierda, D. A.; Whitesides, G. M. J. Am. Chem. Soc. 1994,116, 2382). Four of the complexes pack in the solid state as linear tapes, while the diphenylmelamine-dimethylbarbituric acid complex packs as a crinkled tape due to the closer stacking of tapes permitted by the small methyl substituents. The triad of hydrogen bonds that forms tapes is apparently robust to this sort of variation, even though some of the substituents introduce noncovalent intertape interactions, such as halogen-nitrogen contacts, ionic forces, and other hydrogen bonds. The potential of such intertape interactions for designing crystalline architecture is discussed.