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Ruthenium Ring‐Opening Metathesis Polymerization Catalysts Bearing o ‐ Aryloxide‐N‐Heterocyclic Carbenes
Author(s) -
Kong Yong,
Tang Yungang,
Wang Zunzhi,
Xu Shansheng,
Song Haibin,
Wang Baiquan
Publication year - 2013
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201200509
Subject(s) - romp , norbornene , metathesis , ruthenium , chemistry , ring opening metathesis polymerisation , carbene , polymer chemistry , cyclooctene , polymerization , ring opening polymerization , copolymer , catalysis , polymer , organic chemistry
A series of o ‐aryloxide‐N‐heterocyclic carbene ruthenium complexes 2–4 is synthesized via sequential reactions of the o ‐hydroxyaryl imidazolium proligands (2‐OH‐3,5‐ t Bu 2 C 6 H 2 )(R)(C 3 H 3 N 2 ) + Br − (R = Me ( 1a ), i Pr ( 1b ), Mes ( 1c )) with Ag 2 O and [(C 6 H 6 )RuCl 2 ] 2 . All of the complexes are characterized by 1 H and 13 C NMR spectroscopy, high‐resolution mass spectrometry (HRMS), and elemental analysis. The molecular structure of 2 is determined by single‐crystal X‐ray diffraction analysis. The ring‐opening metathesis polymerization (ROMP) of norbornene (NBE) with 2 – 4 is studied. Among them, complex 4 exhibits the highest activity and efficiency toward ROMP of NBE at 85 °C without any cocatalyst, and the resultant polymers have very high molecular weight (>10 6 Da) and narrow molecular weight distributions. This complex can also efficiently catalyze the alternating copolymerization of NBE and cyclooctene.