Supramolecular Self-Assembly of Dendronized Polymers: Reversible Control of the Polymer Architectures through Acid-Base Reactions

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• 作者：Ken C.-F. Leung ; Paula M. Mendes ; Sergei N. Magonov ; Brian H. Northrop ; Sangcheol Kim ; Kaushik Patel ; Amar H. Flood ; Hsian-Rong Tseng ; J. Fraser Stoddart
• 刊名：Journal of the American Chemical Society
• 出版年：2006
• 出版时间：August 23, 2006
• 年：2006
• 卷：128
• 期：33
• 页码：10707 - 10715
• 全文大小：3841K
• 年卷期：v.128,no.33(August 23, 2006)
• ISSN：1520-5126

文摘

Acid-base switchable supramolecular dendronized polyacetylenes (DPAs) with increasing stericbulk on going from generation one [G1] to three [G3], were constructed using multiple self-assemblyprocesses between Fréchet-type [G1]-[G3]-dendritic dialkylammonium salts and a dibenzo[24]crown-8-containing polymer. The formation of the supramolecular systems is acid-base switchable to either anON (rodlike dendronized polymers) or an OFF (flexible polymers) state. Thus, by controlling thesuperstructures of the supramolecular polymers with the [G1]-[G3] dendrons, it is possible to induceconformational changes within the polymer backbones. The supramolecular dendronized polymers, as wellas their threading-dethreading properties, were characterized by ¹H NMR and UV absorption spectroscopies, gel permeation chromatography (GPC) and light scattering (LS). Independent measures ofmolecular weight (GPC, LS) indicate that DPAs behave as increasingly rigid macromolecules with eachgeneration in solution. Molecular dynamics simulations of each DPA suggest that the lengths of the polymerbackbones increase accordingly. Atomic force microscopy of the [G3]-dendronized polystyrene (DPS), aswell as the DPAs, reveal surface morphologies indicative of aggregated superstructures.