College of Chemistry-Chemical & Environmental Engineering, Weifang University, Weifang, 261061, P. R. China.
Dalton Trans. 2019 Oct 7;48(39):14626-14631. doi: 10.1039/c9dt02852h.
Three boron-pyridyl-isoindoline-1-one based dyes (B1, B2, and B3) with varied side groups were facilely synthesized. Detailed analyses were carried out concerning the crystal conformation, structure dependent photophysical properties and mechanochromic fluorescence (MCF). The MCF behaviours and solid-state emission were demonstrated to be correlated to the different side groups. Upon grinding, the emission of B1 exhibited little changes, whereas reversible MCF with a distinct colour change was observed for B2 and B3. B3 possessing sterically hindered triphenyl amine (TPA) groups showed the most prominent MCF effect. For instance, mechanical grinding resulted in a red-shift of fluorescence from 600 nm to 650 nm. The electronic and steric effects of the donating substituents were found to play important roles in modulating the intramolecular charge-transfer effect and intermolecular interactions. These sensitively and readily tunable mechano-responsive behaviors of the boron-pyridyl-isoindoline-1-one based dyes make them potential candidates for smart fluorescent materials.
三种基于硼-吡啶-异吲哚-1-酮的染料（B1、B2 和 B3）具有不同的侧基，可通过简便的方法合成。对晶体构象、结构依赖性光物理性质和机械变色荧光（MCF）进行了详细分析。MCF 行为和固态发射与不同的侧基有关。研磨后，B1 的发射几乎没有变化，而 B2 和 B3 则表现出可逆的 MCF 和明显的颜色变化。具有空间位阻三苯基胺（TPA）基团的 B3 表现出最显著的 MCF 效应。例如，机械研磨导致荧光从 600nm 红移至 650nm。发现供电子取代基的电子和空间效应在调节分子内电荷转移效应和分子间相互作用方面起着重要作用。这些基于硼-吡啶-异吲哚-1-酮的染料的灵敏且易于调节的机械响应行为使它们成为潜在的智能荧光材料候选物。
