Wall Brian D, Zacca Ashley E, Sanders Allix M, Wilson William L, Ferguson Andrew L, Tovar John D
Department of Chemistry, Krieger School of Arts and Sciences, Johns Hopkins University , 3400 N. Charles St., Baltimore, Maryland 21218, United States.
Langmuir. 2014 May 27;30(20):5946-56. doi: 10.1021/la500222y. Epub 2014 May 14.
We present a systematic study of the photophysical properties of one-dimensional electronically delocalized nanostructures assembled from π-conjugated subunits embedded within oligopeptide backbones. The nature of the excited states within these nanostructures is studied as a function of primary amino acid sequence utilizing steady-state and time-resolved spectroscopies, and their atomistic structure is probed by molecular simulation. Variations introduced into the amino acid side chains at specific residue locations along the molecular peptide backbone lead to pronounced changes in the observed photophysical behavior of the fibrillar structures (spanning H-like excitonic coupling and disordered excimeric coupling) that arise from subtle changes in the π-stacking within them. These results indicate that residue modification-in terms of relative size, solvation properties, and with respect to the distance from the central π-electron core-enables the ability to tune chromophore packing and the resulting photophysics of supramolecular assemblies of π-conjugated bioelectronic materials in a rational and systematic manner.
我们对由嵌入寡肽主链中的π共轭亚基组装而成的一维电子离域纳米结构的光物理性质进行了系统研究。利用稳态和时间分辨光谱研究了这些纳米结构内激发态的性质与一级氨基酸序列的关系，并通过分子模拟探测了它们的原子结构。沿着分子肽主链在特定残基位置引入到氨基酸侧链中的变化，导致了由其内部π堆积的细微变化引起的纤维状结构（跨越类H激子耦合和无序准分子耦合）所观察到的光物理行为发生显著变化。这些结果表明，就相对大小、溶剂化性质以及与中心π电子核的距离而言，残基修饰能够以合理且系统的方式调节发色团堆积以及π共轭生物电子材料超分子组装体的光物理性质。
