Premium
Polar‐Group Activated Isospecific Coordination Polymerization of ortho ‐Methoxystyrene: Effects of Central Metals and Ligands
Author(s) -
Chai Yunjie,
Wang Lingfang,
Liu Dongtao,
Wang Zichuan,
Run Mingtao,
Cui Dongmei
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201805012
Subject(s) - polymerization , chemistry , monomer , steric effects , ligand (biochemistry) , living polymerization , polymer chemistry , chelation , metal , coordination polymerization , polar , stereochemistry , polymer , anionic addition polymerization , organic chemistry , radical polymerization , biochemistry , receptor , physics , astronomy
Stereoselective polymerization of polar vinyl monomers has been a long‐standing challenge because the employed transition‐metal catalysts are easily poisoned by polar groups of monomers. In this contribution, a series of β ‐diketiminato rare‐earth metal complexes 1 – 5 (L 1–5 Ln(CH 2 SiMe 3 ) 2 (THF) n , Ln=Gd–Lu, Y, and Sc) were successfully synthesized. In combination with Al i Bu 3 and [Ph 3 C][B(C 6 F 5 ) 4 ], complexes 1 c (Tb)– 1 g (Tm) exhibited high activities and excellent isoselectivities for the polymerization of ortho ‐methoxystyrene ( o MOS), in which, the polar methoxy group of o MOS did not poison but activated the polymerization through σ–π chelation to the active species together with the vinyl group. Moreover, the large Gd‐attached precursor 1 b showed a higher activity, albeit with a slightly decreased isoselectivity. The small Sc‐attached precursor 1 i was completely inert. Meanwhile, the spatial steric arrangement and the coordination mode of the β ‐diketiminato ligand could clearly affect and even block o MOS polymerization. This work sheds new light on the coordination polymerization of polar monomers.