Charge-Transfer Natures of Alkali Halide-Organic Complexes Revealed by Dual-Mode Antisymmetric Stretching Vibrations of Cyano Groups

作者：Mengmeng Zhang, Siya Huang, Bowei Ye, Jiecheng Chen, Yixin Shao, Wenbin Chen, Xinda Huang, Shunli Chen, Li Dang, Ming‐De Li · 发表于：The Journal of Physical Chemistry C · 年份：2025 · DOI：10.1021/acs.jpcc.4c08626 · 被引用次数：5 · 研究领域：Luminescence and Fluorescent Materials、Mechanical and Optical Resonators、Porphyrin and Phthalocyanine Chemistry

The antisymmetric stretching vibrational mode ( b 1u ν 18 ) of cyano groups is fruitfully used as a sensitive probe for the structural and electronic characterization of TCNQ-/F4TCNQ-based donor–acceptor (D–A) complexes. However, this probe may fail when encountering a small (<0.1) degree of charge-transfer (DCT) situation. Herein, we evaluate the potential of dual-mode ( b 1u ν 18 / b 2u ν 32 ) probes by synthesizing a series of alkali halide-F4TCNQ complexes with a significant red shift absorption (200–2000 nm) by a one-step mechanochemical method. Surprisingly, the b 2u ν 32 mode displays appreciable sensitivity and universality for the small DCT situation and makes up the shortage of the b 1u ν 18 mode. Compared to the monomer, these two modes of complexes exhibit a much broader peak width corresponding to a much faster rate of thermal energy dissipation. This work highlights the potential of dual-mode probes for the characterization of complexes without an ideal crystalline structure and proves the validity of the metal–organic complexation strategy to regulate the near-infrared absorption of organics.