We describe photoinduced formation of blue fluorescent aggregates of azobenzene derivatives, whose isolated molecules in solution are not fluorescent at ambient temperature, with different alkyl chain lengths. In contrast to nonfluorescent C0 (4-hydroxyazobenzene), C10 and C24 with long alkyl chains started being blue fluorescent upon UV light irradiation for 60 min and the fluorescence intensities were more enhanced with increasing UV light irradiation time. Such a striking fluorescence enhancement by UV light irradiation is closely associated with the unique formation of self-assembled nanoaggregates (50–70 nm and 30–60 nm in diameter for C10 and C24, respectively) of cis-azobenzene derivatives with long alkyl chains as a result of intermolecular interaction of azobenzene moieties with long alkyl chains. Moreover, photoinduced blue fluorescence kept stable even after sufficient thermal cis-to-trans isomerization.
我们描述了不同烷基链长度的
偶氮苯衍
生物在光诱导下形成的蓝色荧光聚集体。与无荧光的 C0(
4-羟基偶氮苯)相比,烷基链较长的 C10 和 C24 在紫外光照射 60 分钟后开始发出蓝色荧光,而且荧光强度随着紫外光照射时间的延长而增强。紫外光照射下如此显著的荧光增强与
偶氮苯分子与长烷基链的分子间相互作用形成的具有长烷基链的顺式
偶氮苯衍
生物独特的自组装纳米聚集体(C10 和 C24 的直径分别为 50-70 nm 和 30-60 nm)密切相关。此外,即使经过充分的热顺反异构化,光诱导的蓝色荧光仍能保持稳定。