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Homo‐ and Copolymerization of Strained Cyclic Olefins with New Palladium(II) Complexes Bearing Ethylene‐Bridged Heterodonor Ligands
Author(s) -
AbuSurrah Adnan S.,
Lappalainen Kristian,
Kettunen Mika,
Repo Timo,
Leskelä Markku,
Hodali Hamdallah A.,
Rieger Bernhard
Publication year - 2001
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 - 10.1002/1521-3935(20010301)202:5<599::aid-macp599>3.0.co;2-1
Subject(s) - norbornene , polymer chemistry , copolymer , chemistry , catalysis , carbon monoxide , palladium , ethylene , polymerization , toluene , glass transition , molar mass , polymer , organic chemistry
Abstract Amorphous and high molar mass polymers of norbornene and phenylnorbornene ( endo/exo ratio of 80/20) were prepared by the use of new dicationic palladium(II) single‐component catalysts of the general type [Pd(L∩L)(NCCH 3 ) 2 ](BF 4 ) 2 . [(L∩L) = 2‐(diphenylarsino)‐1‐(methylthio)ethane (S∩As, 1 ) ( 4 ), 2‐(diphenylphosphino)‐1‐methylthio)ethane (S∩P, 2 ) ( 5 ), 1, 2‐bis(diphenylphosphino)ethane (P∩P, 3 ) ( 6 ). With increasing the trans influence of the donor atom in the ligands (P > As > S) the polymerization activity of the catalysts towards polymerization of norbornene increases instantly. Both the molecular weight and the thermal behavior of the polymer can be tailored using ethene as chain transfer agent. Catalyst 4 is also active towards the alternating copolymerization of carbon monoxide and norbornene. The isolated copolymer is highly soluble in toluene, THF and chlorinated solvents. The DSC measurement of the norbornene‐carbon monoxide copolymer showed a melting temperature ( T m ) of 241°C (Δ H f = 47.3 J/g) and a glass transition temperature ( T g ) of 161°C which is about 170°C lower compared to the homopolynorbornene ( T g ≅ 330°C).