title: Sequence Analysis for Alternating Copolymers by MALDI-TOF-MS: Importance of Initiator Selectivity for Comonomer Pair.
abstract: A special initiator for metal-catalyzed living radical polymerization facilitates sequence analyses by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) of alternating copolymers from styrene and maleimide derivatives. The initiator is a malonate-based alkyl halide (DEMM-Br), in which two ester groups are attached on the carbon neighboring to bromide, and poor electron density of the radical species allows determination of next unit to the initiator in resultant alternating copolymers due to the selective initiation to styrene derivative. Thanks to the well-defined α-end group, sequence of the oligomeric products via radical copolymerization of PMS and EMI with DEMM-Br can be more simply analyzed by MALDI-TOF-MS, and indeed the following are clarified: the crossover propagation is almost perfectly controlled regardless of the injection ratio; a minor error event of the disordered alternating sequence containing St-St sequential unit could take place; the minor error can be suppressed with an excess amount of maleimide.
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto, 615-8510, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Nishimori
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto, 615-8510, Japan. ouchi@living.polym.kyoto-u.ac.jp.|Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Kawaguchi, Saitama, 332-0012, Japan. ouchi@living.polym.kyoto-u.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ouchi
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto, 615-8510, Japan. sawamoto@star.polym.kyoto-u.ac.jp.
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Sawamoto
mesh_terms: D000595:Amino Acid Sequence; D015394:Molecular Structure; D011108:Polymers / Q000032:analysis*; D017421:Sequence Analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D011108:Polymers
keywords: alternating copolymerization; maleimides; radical polymerization; selectivity; sequences