title: Simultaneous Chain-Growth and Step-Growth Polymerization of Methoxystyrenes by Rare-Earth Catalysts.
abstract: The simultaneous chain-growth and step-growth polymerization of a monomer is of great interest and importance because it can produce unique macromolecules which are difficult to prepare by other means. However, such a transformation is usually difficult to achieve in one polymerization system because chain-growth polymerization and step-growth polymerization proceed by different reaction mechanisms. Reported here is the simultaneous chain-growth and step-growth polymerization of para- and meta-methoxystyrenes catalyzed by half-sandwich rare-earth alkyl complexes, and the step-growth polymerization proceeds by the C-H polyaddition of anisyl units to vinyl groups. This unprecedented transformation affords a new family of macromolecules containing unique alternating anisole-ethylene sequences. In contrast to para- and meta-methoxystyrenes, ortho-methoxystyrene exclusively undergo syndiospecific, living chain-growth polymerization by continuous C=C bond insertion to give perfect syndiotactic poly(ortho-methoxystyrene) with high molecular weight and narrow polydispersity (rrrr >99 %, Mnup to 280 kg mol-1, Mw/Mn<1.10).
authors: Organometallic Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors: Xiaochao
authors: 0000-0001-5178-7972
authors: X
authors: Shi
authors: Organometallic Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.|Advanced Catalysis Research Group, RIKEN Center for Sustainable Resource Science, Saitama, 351-0198, Japan.
authors: Masayoshi
authors: 0000-0003-2748-9814
authors: M
authors: Nishiura
authors: Organometallic Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.|Advanced Catalysis Research Group, RIKEN Center for Sustainable Resource Science, Saitama, 351-0198, Japan.
authors: Zhaomin
authors: 0000-0003-2841-5120
authors: Z
authors: Hou
keywords: C−H activation; gadolinium; polymerization; rare-earth metals; reaction mechanisms