Department of Biochemistry and Applied Chemistry, National Institute of Technology, Kurume College, 1-1-1 Komorino, Kurume, 830-8555, Japan.
Material Engineering Advanced Course, Advanced Engineering School, National Institute of Technology, Kurume College, 1-1-1 Komorino, Kurume, 830-8555, Japan.
Chem Asian J. 2021 Aug 2;16(15):2136-2145. doi: 10.1002/asia.202100538. Epub 2021 Jun 21.
The regulation of multicolor fluorescence changes in mechanochromic fluorescence (MCF) remains a challenging task. Herein, we report the regulation of MCF using a donor-acceptor structure. Two crystal polymorphs, BTD-pCHO(O) and BTD-pCHO(R) produced by the introduction of formyl groups to an MCF dye, respond to a mechanical stimulus, allowing a three-color fluorescence change. Specifically, the orange-colored fluorescence of the metastable BTD-pCHO(O) polymorph changed to a deep-red color in the amorphous-like state to finally give a red color in the stable BTD-pCHO(R) polymorph. This change occurred by mechanical grinding followed by vapor fuming. The two different crystal packing patterns were selectively regulated by the electronic effect of the introduced functional groups. The two types of selectively formed crystals in BTD(F)-pCHO bearing fluorine atoms, and BTD(OMe)-pCHO bearing methoxy groups, respond to mechanical grinding, allowing for the regulation of multicolor MCL from a three-color change to two different types of two-color changes.
机械变色荧光（MCF）的多色荧光变化的调控仍然是一项具有挑战性的任务。在此，我们报告了使用给体-受体结构来调控 MCF。两种晶体多晶型物，BTD-pCHO(O)和 BTD-pCHO(R)是通过在 MCF 染料中引入甲酰基基团而产生的，对机械刺激做出响应，允许三色彩光变化。具体而言，BTD-pCHO(O)多晶型物的橙色荧光在非晶态下变为深红色，最后在稳定的 BTD-pCHO(R)多晶型物中呈现红色。这种变化是通过机械研磨和蒸气熏制来实现的。两个不同的晶体堆积模式通过引入的官能团的电子效应进行有选择性地调节。在含有氟原子的 BTD(F)-pCHO 和含有甲氧基的 BTD(OMe)-pCHO 中，两种类型的选择性形成的晶体对机械研磨有响应，允许从三色彩光变化到两种不同类型的双色变化来调节多色 MCF。
