Molecular model of J-aggregated pseudoisocyanine fibers
Molecular model of J-aggregated pseudoisocyanine fibers
复制标题
DOI：
10.1063/1.5036656
复制
发表时间：
2018-07-14
影响因子：
4.4
通讯作者：
Bathe, Mark
中科院分区：
文献类型：
--
作者：
Bricker, William P.;Banal, James L.;Bathe, Mark
聚集的花青形成有序的超分子结构，具有长距离有效传输能量的潜力，这是光合捕光复合物的标志。在浓水溶液中，假异氰脲酸（PIC）自发形成纤维，其手性J带从单体0-0跃迁红移1600 cm（-1）。这些纤维的低温透射电子显微镜分析显示平均纤维宽度为2.89 nm，尽管聚集体的分子水平结构目前尚不清楚。为了确定这些PIC纤维的分子模型，使用Frenkel激子模型计算的光谱和动力学进行比较实验。一个手性聚集体模型，其中PIC单体既不平行，也不正交于纤维的长轴被示出复制的实验光谱最密切。该模型可以通过PIC二聚体和单体与纤维末端的顺序结合来物理实现。这些见解的分子聚集模型的水PIC也可以应用到其他类似的菁基超分子配合物的长程能量传输的潜力，一个关键的建筑模块的合理设计的新型激子系统。出版社：AIP Publishing
Aggregated cyanines form ordered supramolecular structures with the potential to transport energy efficiently over long distances, a hallmark of photosynthetic light-harvesting complexes. In concentrated aqueous solution, pseudoisocyanine (PIC) spontaneously forms fibers with a chiral J-band red-shifted 1600 cm(-1) from the monomeric 0-0 transition. A cryogenic transmission electron microscopy analysis of these fibers show an average fiber width of 2.89 nm, although the molecular-level structure of the aggregate is currently unknown. To determine a molecular model for these PIC fibers, the calculated spectra and dynamics using a Frenkel exciton model are compared to experiment. A chiral aggregate model in which the PIC monomers are neither parallel nor orthogonal to the long axis of the fiber is shown to replicate the experimental spectra most closely. This model can be physically realized by the sequential binding of PIC dimers and monomers to the ends of the fiber. These insights into the molecular aggregation model for aqueous PIC can also be applied to other similar cyanine-based supramolecular complexes with the potential for long-range energy transport, a key building block for the rational design of novel excitonic systems. Published by AIP Publishing.