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

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 [H2 dabco]2+ in the non-ferroelectric [H2 dabco][TFSA]2 (TFSA=bis(trifluoromethylsulfonyl)ammonium), we successfully designed enantiomeric ferroelectrics [R and S-2-Me-H2 dabco][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-H2 dabco][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.