Sequence Analysis for Alternating Copolymers by MALDI‐TOF‐MS: Importance of Initiator Selectivity for Comonomer Pair. Issue 17 (8th July 2016)

• Record Type: Journal Article
• Authors: Nishimori, Kana; Ouchi, Makoto; Sawamoto, Mitsuo
• Is Part Of: Macromolecular rapid communications. Volume 37:Issue 17(2016)
• Page Start: 1414
• Page End: 1420
• Publication Date: 2016-07-08
• Subjects: alternating copolymerization -- maleimides -- radical polymerization -- selectivity -- sequences; Macromolecules -- Periodicals; Polymers -- Periodicals; Chemistry -- Periodicals; 547.705
• DOI: 10.1002/marc.201600251
• Languages: English
• ISSNs: 1022-1336

Abstract

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. Abstract : A malonate‐based alkyl halide initiator (DEMM–Br) for metal‐catalyzed living radical polymerization allows sequence analysis by MALDI‐TOF‐MS for alternating copolymer of styrene and maleimide derivatives. Electron density of the radical species from DEMM–Br is poor enough to induce selective initiation to styrene‐based monomer, and thus the unit next to the initiator moiety can be defined to give simpler peak patterns in MALDI‐TOF‐MS spectra.