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Polymerisation of Norbornene Catalysed by Highly Active Tetradentate Chelated α‐Diimine Nickel Complexes
Author(s) -
Li Lidong,
Gomes Pedro T.,
Lemos M. Amélia N. D. A.,
Lemos Francisco,
Fan Zhiqiang
Publication year - 2011
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.201000612
Subject(s) - norbornene , diimine , polymer chemistry , polymerization , catalysis , nickel , chemistry , polymer , addition polymer , chelation , organic chemistry
A series of three recently synthesised tetradentate chelated α‐diimine nickel complexes of the type [NiBr 2 (Ar‐BIAN)] (where Ar = 2‐(1‐R‐1 H ‐1,2,3‐triazol‐4‐yl)phenyl; R = benzyl 1 , 1‐phenylethyl 2 , phenyl 3 ) are used as precatalysts for the polymerisation of norbornene. When activated with MAO, 1 – 3 are highly active catalysts for the production of high molecular weight polynorbornene (e.g., 1.39 × 10 7 g PNB mol Ni −1 · h −1 ). The catalytic activity and polymer molecular weight increase markedly with the initial concentration of norbornene, but both parameters decrease with the reaction time. The characterisation of the polynorbornenes by NMR, GPC/SEC, X‐ray diffraction, and DSC/TGA leads to the assignment of a structure typical of a polynorbornene originated by a coordination vinyl addition mechanism.