polymerization of 4,4′-((4-iodophenoxy)methyl)-2,2′-bipyridine (M-1) with 4,7-diethynylbenzo[2,1,3]-thiadiazole (M-2) via Pd-catalyzed Sonogashira reaction. The fluorescence responses of the polymer towards various transition metal ions were investigated by fluorescence spectra and UV–Vis spectra. The polymer shows green fluorescence under ultraviolet lamp, which can be quenched by Cu2+ completely due to the heavy
grinding to the crystals results in a phasetransition to an amorphous state, which is concomitant with an emission color change from green to yellow. Annealing the amorphous phase at 100 °C induces a phasetransition to another crystalline state, and green emission was observed again. On subsequent heating, the benzothiadiazole-based cyclophane formed a nematic liquid-crystalline phase above 191 °C.
发光环烷的光物理性质传统上在溶液中以孤立状态进行检查。相比之下,发光环烷响应固态外部刺激的行为还没有完全理解。在此,我们报告了具有一个 4,7-双(苯乙炔基)-2,1,3-苯并噻二唑基团的环烷的晶体结构及其机械变色发光。对晶体进行机械研磨会导致相变到无定形状态,这伴随着发射颜色从绿色变为黄色。在 100 °C 下对非晶相进行退火会导致相变到另一种晶态,并再次观察到绿色发射。在随后的加热中,基于苯并噻二唑的环芳在 191 °C 以上形成向列液晶相。这些结果表明,在环状分子结构中引入 π 扩展的平面发光体是设计刺激响应发光材料的一种很有前景的方法。
Phenolic Bis-styrylbenzo[<i>c</i>]-1,2,5-thiadiazoles as Probes for Fluorescence Microscopy Mapping of Aβ Plaque Heterogeneity
A fluorescent bis-styryl-benzothiadiazole (BTD) with carboxylic acid functional groups (X-34/Congo red analogue) showed lower binding affinity toward A beta 1-42 and A beta 1-40 fibrils than its neutral analogue. Hence, variable patterns of neutral OH-substituted bis-styryl-BTDs were generated. All bis-styryl-BTDs showed higher binding affinity to A beta 1-42 fibrils than to A beta 1-40 fibrils. The para-OH on the phenyl rings was beneficial for binding affinity while a meta-OH decreased the affinity. Differential staining of transgenic mouse A beta amyloid plaque cores compared to peripheral coronas using neutral compared to anionic bis-styryl ligands indicate differential recognition of amyloid polymorphs. Hyperspectral imaging of transgenic mouse A beta plaque stained with uncharged para-hydroxyl substituted bis-styryl-BTD implicated differences in binding site polarity of polymorphic amyloid plaque. Most properties of the corresponding bis-styryl-BTD were retained with a rigid alkyne linker rendering a probe insensitive to cis trans isomerization. These new BTDbased ligands are promising probes for spectral imaging of different A beta fibril polymorphs.