Supramolecular Copolymerization by Sequence Reorganization of a Supramolecular Homopolymer

Kouhei Nadamoto; Kei Maruyama; Naoka Fujii; Toshiaki Ikeda; Shin-Ichi Kihara; Takeharu Haino

doi:10.1002/anie.201800980

Supramolecular Copolymerization by Sequence Reorganization of a Supramolecular Homopolymer

Angew Chem Int Ed Engl. 2018 Jun 11;57(24):7028-7033. doi: 10.1002/anie.201800980. Epub 2018 May 24.

Authors

Kouhei Nadamoto¹, Kei Maruyama¹, Naoka Fujii¹, Toshiaki Ikeda^{1

2}, Shin-Ichi Kihara³, Takeharu Haino¹

Affiliations

¹ Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan.
² Present address: Department of Chemistry, School of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa, 259-1292, Japan.
³ Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, 739-8527, Japan.

PMID: 29683539
DOI: 10.1002/anie.201800980

Abstract

The homopolymeric sequence formed by the head-to-head association of tetrakisporphyrin 1 is completely dissociated by the competitive association of the ditopic guest G2, resulting in the supramolecular copolymer poly-1⋅G2 with an alternatingly repeating host-guest sequence. The 1:1 stoichiometry of 1 and G2 is confirmed by a Job plot using UV/Vis titration and diffusion-ordered NMR spectroscopy (DOSY). The solution viscometry for poly-1 and poly-1⋅G2 suggests that the supramolecular chain of poly-1 behaves like a rod, whereas the supramolecular copolymer chain of poly-1⋅G2 behaves like a swelled fat chain, which is entangled in the semi-dilute regime. Atomic force microscopy shows that the supramolecular polymer poly-1⋅G2 is highly oriented through the interdigitation of the long alkyl chains.

Keywords: host-guest complexes; molecular recognition; porphyrins; sequence-regulated copolymers; supramolecular polymers.

Publication types

Research Support, Non-U.S. Gov't