Sequence-regulated copolymerization based on periodic covalent positioning of monomers along one-dimensional nanochannels

• Published in: Nature communications Vol. 9; no. 1; pp. 329 - 6
• Main Authors: Mochizuki, Shuto, Ogiwara, Naoki, Takayanagi, Masayoshi, Nagaoka, Masataka, Kitagawa, Susumu, Uemura, Takashi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23.01.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 639/638/455/941; 639/638/455/959; 639/638/541/965; Acrylonitrile; Coordination polymers; Copolymerization; Copolymers; Copper; Free radicals; Humanities and Social Sciences; Ligands; Magnetic resonance spectroscopy; Monomers; multidisciplinary; NMR; NMR spectroscopy; Nuclear magnetic resonance; Particle size; Periodic structures; Periodicity; Polymerization; Polymers; Science; Science (multidisciplinary); Styrene; Transcription; Vinyl copolymers
• DOI: 10.1038/s41467-017-02736-1
• ISSN: 2041-1723

The design of monomer sequences in polymers has been a challenging research subject, especially in making vinyl copolymers by free-radical polymerization. Here, we report a strategy to obtain sequence-regulated vinyl copolymers, utilizing the periodic structure of a porous coordination polymer (PCP) as a template. Mixing of Cu 2+ ion and styrene-3,5-dicarboxylic acid ( S ) produces a PCP, [Cu(styrene-3,5-dicarboxylate)] n , with the styryl groups periodically immobilized along the one-dimensional channels. After the introduction of acrylonitrile ( A ) into the host PCP, radical copolymerization between A and the immobilized S is performed inside the channel, followed by decomposing the PCP to isolate the resulting copolymer. The predominant repetitive SAAA sequence in the copolymer is confirmed by monomer composition, NMR spectroscopy and theoretical calculations. Copolymerization using methyl vinyl ketone also provides the same type of sequence-regulated copolymer, showing that this methodology has a versatility to control the copolymer sequence via transcription of PCP periodicity at the molecular level. Achieving sequence control in polymers is limited by the relative monomer reactivity and thus often statistically random copolymers are obtained. Here the authors show sequence control in radical polymerizations by immobilising the monomer on a porous coordination polymer and subsequent polymerization with a second free monomer.