Pseudopolymorphism and Polymorphic Transition Behavior of N‑(4′-Methoxyphenyl)-2-naphthalenesulfonamide

The title compound afforded four different types of crystals as pseudopolymorphs upon crystallization from a variety of different solvents. Single-crystal X-ray analysis revealed that the nonsolvated crystals exclusively formed a zigzag chain motif through hydrogen-bonding interactions (H-bonds). In contrast, the solvent-containing crystals formed a helical chain motif through H-bonds to give rise to channel-shaped network structures. The inner spaces of the channels were occupied by solvent molecules from the crystallization solvent. These solvent-containing crystals could be converted to the nonsolvated crystals by removal of the solvent molecules by drying under reduced pressure at 45 °C. They also showed mutual polymorphic transitions via a solvent-exchange process.