Unusual hydrogen-bonding networks consisting of π-extended 4,4′-bipyridines and chloranilic acid

Hydrogen-bonding networks of pi-extended 4,4'-bipyridines, 2,5-di(4-pyridyl)thiophene (1), 2,5-di(4-pyridyl)furan (2) and 1,4-di(4-pyridyl)benzene (3) with 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid, CA) have been investigated. The dipyridyl compounds afforded complexes 4 [(dication of 1)(.)(monoanion of CA)21, 5 [(dication of 2)(.)(dianion of CA)(.)(MeOH)] and 6 [(3)(.)(dication of 3).(dianion of CA)(.)(H2O)(6)] with CA. X-ray structure analyses revealed the formation of unusual molecular tape and sheet structures involving N-H...O, O-(HO)-O-..., C-(HO)-O-... and N-(HN)-N-... hydrogen bonds, where the aromatic spacer groups play an important role in constructing the unique crystal structures.