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Updated: Apr 23, 2026

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
Dynamic behavior, electrochromism, and two-photon absorption of dicyanomethylenated quinacridone
Takashi Takeda1, Hiroyuki Sugihara, Yasutaka Suzuki
1Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , Katahira 2-1-1, Sendai, Miyagi 980-8577, Japan.
Abstract:
Molecular structures of dicyanomethylenated quinacridone (1) as a solid and in solution were examined on the basis of single-crystal X-ray structural analysis, temperature-dependent (1)H NMR in CD2Cl2, and theoretical calculations. Crystal 1 had a curved, butterfly-shaped molecular structure. Thermally activated flipping between the curved, butterfly-shaped structure and an armchair structure occurred in solution. Electrochemical reduction triggered a dynamic change from the curved, butterfly-shaped conformation in the neutral state to a planar conformation in the dianion state, which represented electrochromic behavior with electrochemical bistability. A large two-photon absorption cross section of compound 1 was observed in the resonance-enhancement region of 423 GM (1 GM = 1 × 10(-50) cm(4) s photon(-1) molecule(-1)) at 710 nm. Multiple donor-acceptor charge-transfer pathways of molecule 1 enhanced two-photon absorption.
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