Inversion of Molecular Chirality Associated with Ferroelectric Switching in a High-Temperature Two-Dimensional Perovskite Ferroelectric

Controlling molecular chirality by external stimuli is of great significance in both fundamental research and technological applications. Herein, we report a high-temperature (384 K) molecular ferroelectric of a Cu(II) complex whose spontaneous polarization can be switched associated with flipping of molecular chirality. In this two-dimensional perovskite structure, the inorganic layer is separated by (NH3(CH2)(2)SS(CH2)(2)NH3)(2+) organic cations skewed in a chiral conformation (P- or M-helicity in an individual crystal). As the stereodynamic disulfide bridge determines the molecular dipole moment along the polar axis, the chiral organic cation can be converted to its enantiomer as a consequence of an electric field-induced shift of the S-S moiety relative to its screw axis during the ferroelectric switching. The variation of the molecular chirality is examined with single-crystal X-ray diffraction and circular dichroism spectra. The simultaneous switching of molecular chirality and spontaneous polarization in this perovskite ferroelectric may lead to novel chiral electronic phenomena.

Automated summary

Controlling molecular chirality by external stimuli is achieved in a high-temperature molecular ferroelectric Cu(II) complex. The spontaneous polarization of the complex can be switched by flipping the molecular chirality, with the chiral organic cation being converted to its enantiomer using an electric field-induced shift. This perovskite ferroelectric material with simultaneous switching of molecular chirality and spontaneous polarization may result in novel chiral electronic phenomena.