Title: An Acid-Base Controllable Hierarchical Nanostructure from a NIR-Absorbing Conjugated Polyrotaxane-Based Optical Molecular Switch
Authors: Raju, Mandapati V. Ramakrishnam
Raghunath, P.
Lin, Ming-Chang
Lin, Hong-Cheu
Department of Materials Science and Engineering
Department of Applied Chemistry
Issue Date: 10-Sep-2013
Abstract: To investigate the supramolecular interactions of the mechanically interlocked rotaxane pendants and conjugated polymer backbones, four analogous polymers were systematically synthesized by copolymerization of a 9-alkylidene-9H-fluorene monomer with various monomers, which contained a diketopyrrolopyrrole unit tethered with a dumbbell unit, a metalated [2]rotaxane, a demetalated orthogonal H-bonded [2]rotaxane, and a simple alkyl chain, to furnish P1, P2, P3, and P4, respectively. Prevailing H-1 NMR and UV-vis to NIR titration profiles indicated that the novel polyrotaxane P3 showed a sensitive and reversible acid base molecular switch capability via supramolecular interactions in contrast to the other polymers (P1, P2, and P4). Compared with the other polymers, P3 possessed a narrower bandgap, which was also confirmed by the computational study. Prominently, the monitoring of a controllable nanoself-assembly process of P3 was obtained by reversible acid base molecular switch approaches. The orthogonal H-bonded pendant [2]rotaxane unit and the steric demand of P3 judiciously allowed to morph into a hierarchical nanostructure via interconvertible H-bonds, anion-pi and pi-pi stackings, and hydrophobic interactions.
URI: http://dx.doi.org/10.1021/ma401485b
ISSN: 0024-9297
DOI: 10.1021/ma401485b
Volume: 46
Issue: 17
Begin Page: 6731
End Page: 6743
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