Cationic polymerization of n‐hexyloxyallene by using halogen‐bonding organocatalysts

Abstract

ABSTRACTThe cationic polymerization of n‐hexyloxyallene was investigated by using halogen‐bonding organocatalysts (Cat A–Cat D). Although the neutral catalyst Cat C showed a poor polymerization activity, iodine‐carrying bidentate cationic catalyst Cat A brought about the smooth polymerization giving rise to a polymer with Mn of 2710 under [Cat A]:[IBVE‐HCl]:[monomer] = 10:10:500 in mM concentrations. Judging from the color change of polymerization system and electrospray ionization mass spectra of recovered catalyst, the decomposition of organocatalyst was suggested. When α‐bromodiphenylmethane was used as an initiator, the relatively controlled polymerization proceeded at the low monomer conversion likely due to the weak halogen‐bonding interaction of Cat A with the bromide anion. On the other hand, bromine‐carrying bidentate catalyst Cat D gave low‐molecular‐weight polymers (Mn < 1550) to be less suitable for polymerization. From the 1H‐NMR spectrum, it was found that the 1,2‐polymerization unit and 2,3‐polymerization unit are included in 75:25. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2436–2441