Conformational Transformations of (C 12 H 25 NH 3 + )(Pyridinesulfonate) in the Solid State

The phase‐transition behaviors, crystal structures, and dielectric properties of four kinds of simple 1:1 organic salts of (C 12 H 25 NH 3 + )(benzenesulfonate) and (C 12 H 25 NH 3 + )(pyridine sulfonates) were examined from the viewpoint of intermolecular hydrogen‐bonding interactions and dynamic conformational transformation in molecular assemblies. Crystals of (C 12 H 25 NH 3 + )(benzenesulfonate) and (C 12 H 25 NH 3 + )(3‐pyridinesulfonate) were isostructural and solid–solid and solid–liquid‐crystal smectic A (SmA) phase transitions were observed. These two crystals formed rodlike cation–anion assemblies. However, the two salts, (C 12 H 25 NH 3 + )(2‐pyridinesulfonate) and (C 12 H 25 NH 3 + )(4‐pyridinesulfonate), formed largely bent L ‐shaped cation–anion conformations. Interesting conformational transformations from rodlike to L ‐shaped assemblies were observed in (C 12 H 25 NH 3 + )(2‐pyridinesulfonate) and (C 12 H 25 NH 3 + )(3‐pyridinesulfonate).