Single crystal XRD study of 4,4'-dipyridyl — p -ethoxybenzoic acid and N,N'-dipyridylpiperazine — p -ethoxybenzoic acid co-crystals: Direct evidence of H-bond interaction in the corresponding liquid-crystalline mesogenic phases

摘要

Supramolecular H-bonded complexes formed between p-ethoxybenzoic acid and 4,4'-dipyridyl or N,N'-dipyridylpiperazine were obtained as nematic liquid-crystalline phases. The corresponding crystals suitable for single crystal X-ray analysis were isolated and investigated. The stoichiomtery of complex 1 is (4,4'-dipyridyl)-2(p-ethoxybenzoic acid) and that of complex 2 is (N,N'-dipyridylpiperazine)-2(p-ethoxybenzoic acid). The molecular packing observed in the crystal structures investigated indicates that the mesogenic phases of the complexes are induced by H-bond interactions.