The tendency of boron‐dipyrromethene (BODIPY) dyes to associate in water is well known, and usually a cause for inferior fluorescence properties. Synthetic efforts to chemically improve BODIPYs’ water solubility and minimize this problem have been numerous in the past. However, a deeper understanding of the phenomena responsible for fluorescence quenching is still required. Commonly, the spectroscopic behaviour in aqueous media has been attributed to aggregate or excimer formation, with such works often centring on a single BODIPY family. Herein, we provide an integrating discussion including very diverse types of BODIPY dyes. Our studies revealed that even subtle structural changes can distinctly affect the association behaviour of the fluorophores in water, involving different photophysical processes. The palette of behaviour found ranges from unperturbed emission, to the formation of H or J aggregates and excimers, to the involvement of tightly bound, pre‐formed excimers. These results are a first step to a more generalized understanding of spectroscopic properties vs. structure, facilitating future molecular design of BODIPYs, especially as probes for biological applications.

中文翻译：

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烷基化和退火的硼二吡咯亚甲基（BODIPY）染料在水溶液中的聚集行为和光谱性质

硼二吡咯亚甲基（BODIPY）染料在水中缔合的趋势是众所周知的，通常是导致荧光性能较差的原因。过去，化学方法可以提高BODIPY的水溶性并最大程度地减少这一问题。但是，仍然需要对引起荧光猝灭的现象有更深入的了解。通常，水性介质中的光谱行为归因于聚集体或受激准分子的形成，这类工作通常集中在单个BODIPY系列上。在这里，我们提供了一个综合讨论，包括非常多种类型的BODIPY染料。我们的研究表明，即使微妙的结构变化也可以明显影响水中的荧光团的缔合行为，涉及不同的光物理过程。发现的行为范围从无干扰的发射到H或J聚集体和受激准分子的形成，再到紧密结合的预先形成的受激准分子的参与。这些结果是对光谱性质更全面了解的第一步与。的结构，有利于BODIPY的未来分子设计，尤其是作为生物学应用的探针。