Hayashi Shotaro, Yamamoto Shun-Ya, Takeuchi Daisuke, Ie Yutaka, Takagi Koji
Department of Applied Chemistry, National Defence Academy, 1-10-20 Hashirimizu, Yokosuka, 239-8686, Japan.
Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555, Japan.
Angew Chem Int Ed Engl. 2018 Dec 21;57(52):17002-17008. doi: 10.1002/anie.201810422. Epub 2018 Nov 21.
To create low band-gap, fluorescent, and elastic organic crystal emitters, we focused on an extended π-conjugated system based on: a) a planar conformation,b) a rigid structure, and c) controlled intermolecular interactions. Herein, we report on two fluorescent and highly flexible organic crystals (1 and 2) which could bend under an applied stress. The bent crystals rapidly recover their straight shape upon release of the stress. Crystal 1 with a tetrafluoropyridyl terminal unit and a lower band-gap energy (orange emission, λ =573 nm, Φ =0.50), showed no bending mechanofluorochromism and had superior performance as an optical waveguide with reddish orange emission. The waveguide performance of the crystal did not decrease under bending stress. For crystal 2 with a pentafluorophenyl terminal unit (green emission, λ =500 nm, Φ =0.38), the original waveguide performance decreased under an applied bending stress; however, this crystal showed a unique bending mechanofluorochromism.
为了制备低带隙、荧光性和弹性的有机晶体发光体，我们专注于基于以下几点的扩展π共轭体系：a）平面构象，b）刚性结构，以及c）可控的分子间相互作用。在此，我们报道了两种荧光性且高度柔性的有机晶体（1和2），它们在施加应力下能够弯曲。释放应力后，弯曲的晶体迅速恢复其直线形状。具有四氟吡啶基末端单元且带隙能量较低（橙色发射，λ = 573 nm，Φ = 0.50）的晶体1，未表现出弯曲机械变色荧光现象，并且作为具有红橙色发射的光波导具有优异性能。该晶体的光波导性能在弯曲应力下不会降低。对于具有五氟苯基末端单元的晶体2（绿色发射，λ = 500 nm，Φ = 0.38），施加弯曲应力时其原始光波导性能下降；然而，该晶体表现出独特的弯曲机械变色荧光现象。
