Beijing National Laboratory for Molecular Sciences, Chemistry, Center for the Soft Matter Science and Engineering and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China.
Department of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300072, China.
Angew Chem Int Ed Engl. 2022 Sep 12;61(37):e202208635. doi: 10.1002/anie.202208635. Epub 2022 Aug 3.
A molecule featuring two distinct cooperatively grown J-aggregates is investigated. Interestingly, when cooling a hot monomer solution, the thermodynamically less stable J is exclusively formed even at a particularly slowed temperature dropping rate, which transforms to the more stable J at room temperature with very slow kinetics. This observation is ascribed to the differed nucleus sizes of J and J . During the cooling process, smaller J nuclei are formed first at a higher temperature, favored by the entropy effect. At intermediate temperatures, the elongation of J out-competes the nucleation of J . Then, below the elongation temperature of J , the formation of this thermodynamically stable aggregate is hindered kinetically, due to the depletion of monomer by the slow dissociation of J . Additional evidence proving the larger nucleus size of J is also identified with the varied-temperature spectral analyses and mathematic simulations.
研究了一种具有两个独特协同生长 J-聚集体的分子。有趣的是，当冷却热单体溶液时，即使在特别缓慢的降温速率下，热力学上不太稳定的 J 也会被优先形成，而在室温下，J 的形成速度非常缓慢，这是动力学控制的结果。这种观察结果归因于 J 和 J 的核大小不同。在冷却过程中，较小的 J 核首先在较高温度下形成，这是熵效应的结果。在中间温度下，J 的伸长竞争过 J 的成核。然后，在 J 的伸长温度以下，由于 J 的缓慢解离消耗了单体，这种热力学稳定的聚集体的形成受到动力学的阻碍。通过变温光谱分析和数学模拟也确定了 J 的核大小较大的额外证据。
