Borsdorf Lorenz, Herkert Lorena, Bäumer Nils, Rubert Llorenç, Soberats Bartolome, Korevaar Peter A, Bourque Cole, Gatsogiannis Christos, Fernández Gustavo
Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, Corrensstraße 36, 48149 Münster, Germany.
Department of Chemistry, Universitat de les Iles Balears, Cra. Valldemossa, Km. 7.5, 07122 Palma de Mallorca, Spain.
J Am Chem Soc. 2023 Apr 26;145(16):8882-8895. doi: 10.1021/jacs.2c12442. Epub 2023 Apr 13.
Solute-solvent interactions play a critical role in multiple fields, including biology, materials science, and (physical) organic, polymer, and supramolecular chemistry. Within the growing field of supramolecular polymer science, these interactions have been recognized as an important driving force for (entropically driven) intermolecular association, particularly in aqueous media. However, to date, solute-solvent effects remain poorly understood in the context of complex self-assembly energy landscapes and pathway complexity. Herein, we unravel the role of solute-solvent interactions in controlling chain conformation effects, allowing energy landscape modulation and pathway selection in aqueous supramolecular polymerization. To this end, we have designed a series of oligo(phenylene ethynylene) (OPE)-based bolaamphiphilic Pt(II) complexes - bearing solubilizing triethylene glycol (TEG) chains of equal length on both molecule ends, but a different size of the hydrophobic aromatic scaffold. Strikingly, detailed self-assembly studies in aqueous media disclose a different tendency of the TEG chains to fold back and enwrap the hydrophobic molecular component depending on both the size of the core and the volume fraction of the co-solvent (THF). The relatively small hydrophobic component of can be readily shielded by the TEG chains, leading to only one aggregation pathway. In contrast, the decreased capability of the TEG chains to effectively shield larger hydrophobic cores ( and ) enables different types of solvent quality-dependent conformations (extended, partly back-folded and back-folded), which in turn induce various controllable aggregation pathways with distinct morphologies and mechanisms. Our results shed light on previously underappreciated solvent-dependent chain conformation effects and their role in governing pathway complexity in aqueous media.
溶质 - 溶剂相互作用在多个领域发挥着关键作用，包括生物学、材料科学以及（物理）有机化学、高分子化学和超分子化学。在不断发展的超分子聚合物科学领域中，这些相互作用已被认为是（熵驱动的）分子间缔合的重要驱动力，尤其是在水性介质中。然而，迄今为止，在复杂的自组装能量景观和途径复杂性的背景下，溶质 - 溶剂效应仍未得到很好的理解。在此，我们揭示了溶质 - 溶剂相互作用在控制链构象效应中的作用，从而实现水性超分子聚合中的能量景观调制和途径选择。为此，我们设计了一系列基于寡聚（亚苯基乙炔）（OPE）的双极性Pt（II）配合物——在分子两端带有等长的增溶三甘醇（TEG）链，但疏水芳族支架的尺寸不同。引人注目的是，在水性介质中的详细自组装研究表明，取决于核心尺寸和共溶剂（THF）的体积分数，TEG链回折并包裹疏水分子成分的趋势不同。 相对较小的疏水性成分可以很容易地被TEG链屏蔽，从而只导致一种聚集途径。相比之下，TEG链有效屏蔽较大疏水核心（ 和 ）的能力下降，使得能够形成不同类型的溶剂质量依赖性构象（伸展的、部分回折的和回折的），这反过来又诱导出具有不同形态和机制的各种可控聚集途径。我们的结果揭示了以前未被充分认识的溶剂依赖性链构象效应及其在控制水性介质中途径复杂性方面的作用。
