Preparation and Structures of Multicomponent Crystals Composed of Heteraromatic Cations, p‐Toluenesulfonate Anion, and Aromatic Hydrogen‐Bond Donors

Cocrystals with three π‐components, which were a π‐cation, a π‐anion acting as a hydrogen‐bonding acceptor, and a π‐molecule acting as a hydrogen‐bonding donor, were prepared by the solution‐growth methods. The first and second components were ion pairs of 1‐methylpyridinium or 1‐methylquinolinium p‐toluenesulfonate derivatives, and the third components were dihydric phenol derivatives, like hydroquinone, 1,4‐naphthalenediol, 4,4’‐biphenol, and 1,1’‐bi‐2‐naphthol, or benzoic acid derivatives with hydroxy or amino group at the para position. Among 23 cocrystals found from 35 possible combinations of five ion‐pairs and seven hydrogen‐bonding donors, 20 cocrystals were investigated by the X‐ray crystallographic analyses. Some of them also contained solvent molecules. In these cocrystals, hydrogen‐bonding sequences composed of p‐toluenesulfonate and the hydrogen‐bonding donors were observed, and ionic bonds between the first and second components and hydrogen bonds between the second and third components were found to be responsible for three‐π‐component cocrystals. When the cations were 4‐cyanopyridinium or quinolinium derivatives, the cocrystals showed charge‐transfer absorption bands due to electronic interaction between the cations and the hydrogen‐bonding donors. To the mixture of quinolinium p‐toluenesulfonate and 1,1’‐bi‐2‐naphthol forming the three‐π‐component cocrystals, tetrathiafulvalene were added to form four‐π‐component cocrystals with ethanol or water molecules.