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Ferroelectric Behavior of a Hexamethylenetetramine‐Based Molecular Perovskite Structure
Author(s) -
Morita Hagino,
Tsunashima Ryo,
Nishihara Sadafumi,
Inoue Katsuya,
Omura Yuriko,
Suzuki Yasutaka,
Kawamata Jun,
Hoshino Norihisa,
Akutagawa Tomoyuki
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201905087
Subject(s) - hexamethylenetetramine , ferroelectricity , chemistry , crystallography , perovskite (structure) , hydrogen bond , crystal structure , molecule , curie temperature , polarization (electrochemistry) , inorganic chemistry , materials science , dielectric , ferromagnetism , organic chemistry , physics , optoelectronics , quantum mechanics
We report the development of a molecular ferroelectric material inspired by the hexamethylenetetramine (hmta) non‐centrosymmetric molecular rotator. The bromide salt of diprotonated hmta (hmtaH 2 ) crystalized as (hmtaH 2 )(NH 4 )Br 3 in a metal‐free ABX 3 perovskite‐type structure, in which the A and B sites are occupied by hmtaH 2 2+ and ammonium cations, respectively. The compound crystallized in the P ma2 polar space group. A distorted polar perovskite structure formed owing to the distortion of {(NH 4 )Br 6 } octahedrons that are stabilized through the formation of NH⋅⋅⋅Br hydrogen bonds and the orientational ordering of positive charges on the non‐centrosymmetric hmtaH 2 molecules. This spontaneous polarization exhibited ferroelectric behavior with a nominally high Curie temperature (>400 K), in which the electrical switching of polarization originates from the rotation of the hmtaH 2 unit.