High‐Tc Enantiomeric Ferroelectrics Based on Homochiral Dabco‐derivatives (Dabco=1,4‐Diazabicyclo[2.2.2]octane)

• Published in: Angewandte Chemie International Edition Vol. 59; no. 40; pp. 17477 - 17481
• Main Authors: Fu, Da‐Wei, Gao, Ji‐Xing, He, Wen‐Hui, Huang, Xue‐Qin, Liu, Yu‐Hua, Ai, Yong
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 28.09.2020
• Edition: International ed. in English
• Subjects: Ammonium; chirality; Derivatives; Enantiomers; ferroelectric domains; Ferroelectric materials; Ferroelectricity; Ferroelectrics; molecular ferroelectrics; Phase transitions; polarization switching; Transition temperature; Transition temperatures
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202007660

1,4‐Diazabicyclo[2.2.2]octane (dabco) and its derivatives have been extensively utilized as building units of excellent molecular ferroelectrics for decades. However, the homochiral dabco‐based ferroelectric remains a blank. Herein, by adding a methyl (Me) group accompanied by the introduction of homochirality to the [H2dabco]2+ in the non‐ferroelectric [H2dabco][TFSA]2 (TFSA=bis(trifluoromethylsulfonyl)ammonium), we successfully designed enantiomeric ferroelectrics [R and S‐2‐Me‐H2dabco][TFSA]2. The two enantiomers show two sequential phase transitions with transition temperature (Tc) as high as 405.8 K and 415.8 K, which is outstanding in both dabco‐based ferroelectrics and homochiral ferroelectrics. To our knowledge, [R and S‐2‐Me‐H2dabco][TFSA]2 are the first examples of dabco‐based homochiral ferroelectrics. This finding opens an avenue to construct dabco‐based homochiral ferroelectrics and will inspire the exploration of more eminent enantiomeric molecular ferroelectrics. The first examples of homochiral dabco‐based (dabco=1,4‐diazabicyclo[2.2.2]octane) ferroelectrics, [R‐ and S‐2‐Me‐H2dabco][TFSA]2 (TFSA=bis(trifluoromethylsulfonyl)ammonium), were designed from the non‐ferroelectric [H2dabco][TFSA]2. They show two phase transitions with a transition temperature (Tc) up to 405.8 K and 415.8 K, higher than the Tc of most dabco‐based or homochiral ferroelectrics.