10.1021/jacs.8b13223.s004 Chen-Kai Yang Chen-Kai Yang Wang-Nan Chen Wang-Nan Chen Yan-Ting Ding Yan-Ting Ding Jing Wang Jing Wang Yin Rao Yin Rao Wei-Qiang Liao Wei-Qiang Liao Yongfa Xie Yongfa Xie Wennan Zou Wennan Zou Ren-Gen Xiong Ren-Gen Xiong Directional Intermolecular Interactions for Precise Molecular Design of a High‑<i>T</i><sub>c</sub> Multiaxial Molecular Ferroelectric American Chemical Society 2019 OH ferroelectric substituent groups Curie temperature 6 equiv building blocks quinuclidinium quasi-spherical ones crystal symmetry 457 K CH quasi-spherical molecule building blocks Directional Intermolecular Interactions crystal structure Precise Molecular Design Systematic characterization hydrogen-bonding interactions modification oxoquinuclidinium Pna 2 1 space group room temperature multiaxial feature 2019-01-07 00:00:00 Dataset https://acs.figshare.com/articles/dataset/Directional_Intermolecular_Interactions_for_Precise_Molecular_Design_of_a_High_i_T_i_sub_c_sub_Multiaxial_Molecular_Ferroelectric/7597553 Quasi-spherical molecules have recently been developed as promising building blocks for constructing high-performance molecular ferroelectrics. However, although the modification of spherical molecules into quasi-spherical ones can efficiently lower the crystal symmetry, it is still a challenge to precisely arouse a low-symmetric polar crystal structure. Here, by introducing directional hydrogen-bonding interactions in the molecular modification, we successfully reduced the cubic centrosymmetric <i>Pm</i>3̅<i>m</i> space group of [quinuclidinium]­ClO<sub>4</sub> at room temperature to the orthorhombic polar <i>Pna</i>2<sub>1</sub> space group of [3-oxoquinuclidinium]­ClO<sub>4</sub>. Different from the substituent groups of −OH, −CH<sub>3</sub>, and CH<sub>2</sub>, the addition of a O group with H-acceptor to [quinuclidinium]<sup>+</sup> forms directionally N–H···OC hydrogen-bonded chains, which plays a critical role in the generation of polar structure in [3-oxoquinuclidinium]­ClO<sub>4</sub>. Systematic characterization indicates that [3-oxoquinuclidinium]­ClO<sub>4</sub> is an excellent molecular ferroelectric with a high Curie temperature of 457 K, a large saturate polarization of 6.7 μC/cm<sup>2</sup>, and a multiaxial feature of 6 equiv ferroelectric axes. This work demonstrates that the strategy of combining quasi-spherical molecule building blocks with directional intermolecular interactions provides an efficient route to precisely design new eminent molecular ferroelectrics.