Supramolecular architectures of cyclohexane-1, 3cis, 5cis-tricarboxylic acid in acid∶base complexes

Abstract

Cyclohexane-1, 3cis, 5cis-tricarboxylic acid (CTA) has been co-crystallised with a range of organic bases containing one, two or more hydrogen bond acceptors. Various supramolecular acid motifs have been identified, including tapes, sheets and interpenetrating networks. Supramolecular zigzag tapes are observed in the 1∶1 co-crystal structure of CTA with acetonitrile (An) and in the 1∶1∶2 co-crystal with 1,10-phenanthroline (oPh) and methanol. In the 1∶1 co-crystal structures of CTA with 4,4′-bipyridyl (Bipy) and with 2-aminopyrimidine (APY), two types of linear supramolecular acid tapes are observed. Co-crystallisation with hexamethyltetramine (HMTA) in the molar ratio of 1∶1 results in supramolecular acid networks with pseudo-hexagonal grids, with HMTA located within the network cavities. Strong O–H⋯O and weak C–H⋯O hydrogen bonds are observed between CTA molecules in these structures.