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Updated: Sep 20, 2025

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
Photoinduced Phase Transition of Ce-UiO-66 to Ce-BDC-OH
Zhixiong Guo1, Qian-Cheng Luo1, Lei Qin2
1Center for Applied Chemical Research, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710054, China.
Abstract:
External stimuli-responsive phase transition of metal-organic frameworks (MOFs) introduces intriguing functions for diverse applications under practical settings. Herein, we reported a phase transition from cubic Ce-UiO-66 to triclinic Ce-BDC-OH under light irradiation. Such a phase transition underwent a ligand-to-metal charge transfer process, which was unambiguously revealed by Fourier transform infrared spectroscopy, nuclear magnetic resonance, electron paramagnetic resonance, etc. We proposed a phase transition mechanism through (1) the photoreduction of the metal core from Ce4+ into Ce3+; (2) the photogeneration of •OH and hydroxylation of BDC into BDC-OH; and (3) the carboxylate migration and lattice rearrangement for transitions. The phenomenon of the Ce4+-to-Ce3+ reduction also enables a diamagnetism-to-paramagnetism transition, suggesting its potential as a photostimulus-responsive magnetic switch.
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