Two-Component Self-Assembly: Hierarchical Formation of pH-Switchable Supramolecular Networks by π-π Induced Aggregation of Ion Pairs

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• 作者：Dr. Krishnananda Samanta ; Martin Ehlers and Prof. Dr. Carsten Schmuck
• 刊名：Chemistry - A European Journal
• 出版年：2016
• 出版时间：October 17, 2016
• 年：2016
• 卷：22
• 期：43
• 页码：15242-15247
• 全文大小：3152K
• ISSN：1521-3765

文摘

Two-component self-assembly is a promising approach to construct functional nanomaterials. Interaction of a flexible guanidiniocarbonyl pyrrole tetra-cation (1) with naphthalene diimide dicarboxylic acid (NDIDC) in aqueous DMSO leads to the formation of supramolecular networks. First, the carboxylate groups of NDIDC bind to the guanidiniocarbonyl pyrrole cations of 1 in a 1:2 stoichiometry. Further π–π induced aggregation then leads to 3D networks, as established by dynamic light scattering studies (DLS), NMR, fluorescence titration, viscosity measurements, AFM, and TEM microscopy. Due to ion pairing, the resulting aggregates can be switched between the monomers and the aggregates reversibly using external stimuli like protonation or deprotonation. At high concentration, a stable colloidal solution is formed, which shows an extensive Tyndall effect. Increasing the concentrations even further leads to formation of a supramolecular gel.