A new amphiphilic boron-dipyrromethene (BODIPY) dye bearing a hydrophobic 2,3,4-tris (n-dodecyloxy) phenyl group at the meso-position and two hydrophilic cationic moieties at the boron was synthesized. This dye exhibited kinetic-controlled and thermodyanmic-controlled aggregation pathways in the aqueous solution, leading to the formation of two type of J-aggregates, i.e. the metastable Agg. I and thermodynamically more stable Agg. II. Further kinetic analysis of spontaneous transformation from Agg. I to Agg. II indicated that the Agg. I was an off-pathway aggregate species. Moreover, both of Agg. I and Agg. II displayed J-aggregate characteristics with enhanced fluoresence quantum yields and shortened fluoresence lifetime with respect to that of the monomeric dye. In particular, the Agg. II exhibited a narrowed and intensive J-band, reflecting the strong excitonic coherence in the aggregate. The morphological studies revealed that Agg. I was spherical nanoparticles while Agg. II had a multilamellar vesicular structure. In addition, in the fluorescence spectra of Agg. I and Agg. II an unexpected broad band at longer wavelength than that of the J-aggregate emission was observed, which could be ascribed to the possible formation of excimers in these J-aggregates in aqueous solution.

中文翻译：

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离子 BODIPY 两亲物的水性 J 聚集中的路径复杂性


合成了一种新型两亲性硼二吡咯亚甲基（BODIPY）染料，其中间位带有疏水性2,3,4-三（正十二烷氧基）苯基，硼上带有两个亲水性阳离子部分。该染料在水溶液中表现出动力学控制和热力学控制的聚集途径，导致形成两种类型的 J-聚集体，即亚稳态 Agg。 I和热力学上更稳定的Agg。二. Agg 自发转化的进一步动力学分析。我对阿格。 II 表明 Agg。我是一个偏离轨道的聚合物种。而且，Agg 都是。我和阿格。相对于单体染料，II 显示出 J 聚集体特征，具有增强的荧光量子产率和缩短的荧光寿命。特别是，Agg。 II 表现出狭窄且密集的 J 带，反映了聚集体中强烈的激子相干性。形态学研究表明 Agg。我是球形纳米粒子，而Agg。 II具有多层囊泡结构。此外，在Agg的荧光光谱中。我和阿格。 II 观察到比 J-聚集体发射波长更长的意想不到的宽带，这可能归因于这些 J-聚集体在水溶液中可能形成准分子。