Novel supramolecular conjugated polyrotaxane as an acid-base controllable optical molecular switch

Abstract

To study the supramolecular interactions of the mechanically interlocked rotaxane pendants with the backbone of two comparable conjugated polymers, axle polymer P1 and polyrotaxane P2 were synthesized by copolymerization of fluorine-based monomer F with phenanthroimidazole (PIZ)-based axle monomer A and rotaxane monomer R, respectively. Prevailing H-1 NMR, UV-vis and PL profiles revealed that polyrotaxane P2 showed sensitive and reversible acid-base molecular switching properties via supramolecular interactions in contrast to the other analogous polymer P1. The capability of molecular switching is also proven by computational study. Apparently, the controllable nano self-assembly process of P2 was fulfilled by reversible acid-base molecular switch approaches, where the orthogonal H-bonded polyrotaxane units were converted from bloated form into flake form on protonation. (C) 2016 Elsevier B.V. All rights reserved.