Premium
Ethene/Norbornene Copolymerization with Palladium( II ) α ‐Diimine Catalysts: From Ligand Screening to Discrete Catalyst Species
Author(s) -
Kiesewetter Jens,
Kaminsky Walter
Publication year - 2003
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.200390201
Subject(s) - norbornene , diimine , palladium , copolymer , catalysis , polymer chemistry , differential scanning calorimetry , metallocene , chemistry , polymer , organic chemistry , polymerization , physics , thermodynamics
Sixteen palladium( II ) α ‐diimine catalysts were investigated in a screening‐like procedure for the copolymerization of ethene with norbornene. The resulting copolymers were characterized by 13 C NMR spectroscopy, differential scanning calorimetry, gel permeation chromatography, and viscosimetry. The degree of incorporation of norbornene in the polymer chain is very high for most of the catalysts. To validate the results achieved in the screening, two catalysts, [{ArNCHCHNAr}Pd(Me)(CH 3 CN)]BAr f 4 ( 1 b′ ; Ar=2,6‐Me 2 C 6 H 3 , BAr f 4 =B[3,5‐C 6 H 3 (CF 3 ) 2 ] 4 ) and [{ArNC(CH 3 )C(CH 3 )NAr}Pd(Me)(CH 3 CN)]BAr f 4 ( 2 c′ ; Ar=2,6‐ i Pr 2 C 6 H 3 ), were synthesized as discrete catalytically active species, and their copolymerization behavior was investigated in detail. In agreement with the screening results, 1 b′ incorporates norbornene much better in the polymer chain than ethene, a property that has no analogue in metallocene catalysts.