A Rotorlike Supramolecular Assembly, {[K(18-crown-6)]PbI₃}_∞, with a Reversible Breaking-Symmetry Phase Transition near Room Temperature

Abstract

A rotorlike supramolecular crystal, {[K(18-crown-6)]PbI3}∞, is composed of a linear [PbI3]∞ chain acting as a stator and [K(18-crown-6)]+ cations fastened to the [PbI3]∞ chain and K–I bond like rotators and axes, respectively. A reversible breaking-symmetry phase transition occurs at ∼305 K. Variable-temperature 1H NMR spectra and dielectrics were used for the dynamic analysis of [K(18-crown-6)]+ cations in the crystal.