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A Rotorlike Supramolecular Assembly, {[K(18-crown-6)]PbI3}∞, with a Reversible Breaking-Symmetry Phase Transition
Guo-Jun Yuan1,2, Dong-Sheng Shao2, Bing-Wen Hu3
1Key Laboratory of Advanced Functional Materials of Nanjing, Department of Chemistry , Nanjing Xiaozhuang University , Nanjing 211171 , P. R. China.
A novel rotorlike crystal structure, {[K(18-crown-6)]PbI3}∞, exhibits a reversible phase transition around 305 K. This transition involves dynamic [K(18-crown-6)]+ cations acting as rotators within the crystal lattice.
Area of Science:
- Materials Science
- Crystallography
- Supramolecular Chemistry
Background:
- Supramolecular crystals offer unique structural motifs and properties.
- Investigating dynamic components within crystal lattices is crucial for understanding phase transitions.
Purpose of the Study:
- To characterize a novel rotorlike supramolecular crystal, {[K(18-crown-6)]PbI3}∞.
- To analyze the dynamic behavior of [K(18-crown-6)]+ cations and their role in phase transitions.
Main Methods:
- Synthesis and structural characterization of {[K(18-crown-6)]PbI3}∞.
- Variable-temperature 1H Nuclear Magnetic Resonance (NMR) spectroscopy.
- Dielectric spectroscopy for dynamic analysis.
Main Results:
- A unique rotorlike crystal structure {[K(18-crown-6)]PbI3}∞ was identified, featuring a [PbI3]∞ chain stator and [K(18-crown-6)]+ rotators.
- A reversible breaking-symmetry phase transition was observed at approximately 305 K.
- Dynamic analysis confirmed the rotational motion of [K(18-crown-6)]+ cations.
Conclusions:
- The {[K(18-crown-6)]PbI3}∞ crystal exhibits interesting structural dynamics and a distinct phase transition.
- The [K(18-crown-6)]+ cations play a key role in the observed phase transition through their rotational motion.
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