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Copolymerization of styrene with CO catalysed by palladium‐substituted 1,10‐phenanthroline bis(methoxycarbonyl) complexes [Pd(L—L)(COOMe) 2 ]
Author(s) -
Santi Roberto,
Romano Anna Maria,
Garrone Rossella,
Abbondanza Luigi,
Scalabrini Mario,
Bacchilega Giancarlo
Publication year - 1999
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/(sici)1521-3935(19990101)200:1<25::aid-macp25>3.0.co;2-#
Subject(s) - palladium , copolymer , chemistry , polymer chemistry , styrene , catalysis , ligand (biochemistry) , tacticity , medicinal chemistry , organic chemistry , polymerization , polymer , biochemistry , receptor
A new class of highly effective homogeneous palladium bis(methoxycarbonyl) complexes Pd(L—L)(COOMe) 2 , where (L—L) are substituted phenanthroline ligands, has been developed for the production of syndiotactic alternating styrene‐carbon monoxide copolymers. The essential feature of this novel catalytic system is that it is formed by palladium complex, Pd(L—L)(COOMe) 2 , an acid cocatalyst, (L—L)HPF 6 , bearing a weakly coordinating counter anion, and an oxidant, such as 1,4‐naphthoquinone (1,4‐NQ). The palladium/acid cocatalyst molar ratio has been explored. A maximum of copolymerization activity was obtained at 1/1 molar ratio. For a series of palladium catalysts, Pd(phen)(COOMe) 2 appeared to be the most active one. The effect of substituents at the ligand in Pd(L—L)(COOMe) 2 on the copolymerization activity was studied. The tacticity of alternating copolymers obtained with different Pd(L—L)(COOMe) 2 catalysts was determined by NMR spectroscopy. The copolymers were thermally characterised by TGA and DSC.