Crown ether inclusion compound 3,4-difluoroanilinium di(methanesulfonyl)amidate-18-crown-6 (1/1) clathrate

In recent years, molecular-based ferroelectric materials have attracted widespread research interest due to their excellent performance. Among them, host-guest-type crown ether inclusion compounds composed of organic ammonium cations, crown ether molecules and corresponding anions have become a star component in the design of molecular-based ferroelectric materials because they are prone to order-disorder phase transitions. Many anions have been studied extensively as counter-ions, such as bis(trifluoromethanesulfonyl)amidate (TFSA^-), PF₆^- and [FeCl₄]^-. However, crown ether inclusion compounds with di(methanesulfonyl)amidate (DMSA) as the anion have been rarely investigated. Here, we converted TFSA to DMSA to obtain 3,4-difluoroanilinium di(methanesulfonyl)amidate-18-crown-6 (1/1), C₆H₆F₂N⁺·C₂H₆NO₄S₂^-·C₁₂H₂₄O₆ or [(3,4-DFA)(18-crown-6)][DMSA]. At both 100 and 300 K, the crystal falls into the space group P2₁/c. The 3,4-DFA cation forms three well-defined N-H...O hydrogen bonds, positioned at the perching position of the crown ether ring. In contrast to the distinct packing configuration observed in the [(3,4-DFA)(18-crown-6)][TFSA] crystals, where TFSA exhibits a disordered structure, the [(3,4-DFA)(18-crown-6)][DMSA] complex features a staggered arrangement, with DMSA existing in an ordered fashion.