Carter Jake G, Pfukwa Rueben, Riley Liam, Tucker James H R, Rodger Alison, Dafforn Timothy R, Klumperman Bert
School of Chemistry, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TT, U.K.
School of Biosciences, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TT, U.K.
ACS Omega. 2021 Nov 24;6(48):33231-33237. doi: 10.1021/acsomega.1c06139. eCollection 2021 Dec 7.
Controllable higher-order assembly is a central aim of macromolecular chemistry. An essential challenge to developing these molecules is improving our understanding of the structures they adopt under different conditions. Here, we demonstrate how flow linear dichroism (LD) spectroscopy is used to provide insights into the solution structure of a chiral, self-assembled fibrillar foldamer. Poly(-aryltriazole)s fold into different structures depending on the monomer geometry and variables such as solvent and ionic strength. LD spectroscopy provides a simple route to determine chromophore alignment in solution and is generally used on natural molecules or molecular assemblies such as DNA and M13 bacteriophage. In this contribution, we show that LD spectroscopy is a powerful tool in the observation of self-assembly processes of synthetic foldamers when complemented by circular dichroism, absorbance spectroscopy, and microscopy. To that end, poly(-aryltriazole)s were aligned in a flow field under different solvent conditions. The extended aromatic structures in the foldamer give rise to a strong LD signal that changes in sign and in intensity with varying solvent conditions. A key advantage of LD is that it only detects the large assemblies, thus removing background due to monomers and small oligomers.
可控的高阶组装是大分子化学的核心目标。开发这些分子面临的一个关键挑战是加深我们对它们在不同条件下所采取结构的理解。在此，我们展示了如何利用流动线性二色性（LD）光谱来深入了解一种手性自组装纤维状折叠体的溶液结构。聚（芳基三唑）会根据单体几何形状以及诸如溶剂和离子强度等变量折叠成不同结构。LD光谱提供了一种确定溶液中发色团排列的简单方法，通常用于天然分子或分子组装体，如DNA和M13噬菌体。在本论文中，我们表明，当与圆二色性、吸收光谱和显微镜技术相结合时，LD光谱是观察合成折叠体自组装过程的有力工具。为此，聚（芳基三唑）在不同溶剂条件下于流场中排列。折叠体中延伸的芳香结构产生了强烈的LD信号，该信号的符号和强度会随溶剂条件的变化而改变。LD的一个关键优势在于它仅检测大型组装体，从而消除了单体和小寡聚物造成的背景干扰。
