Control of Molecular Weight in α-Olefin−Carbon Monoxide Alternating Copolymerization. A Way to High Molecular Weight Propene−Carbon Monoxide Thermoplastic Elastomers

Cationic nickel and palladium complexes with bidentate ligands for the CC linkage of olefins

“…Activation of other diimine nickel compounds, such as allyl complexes [14d,66] Sen et al have applied the compound, respectively its reaction products with monodentate phosphines, as precursor to C C linkage reactions of olefins, such as the oligomerization of ethylene and a-olefins, the slow copolymerization of ethylene with CO, or the polymerization of styrene [117]. Later, Sen and coworkers [118] and others [119,120], applied the (much more active) catalyst system obtained from [Pd(NCCH 3 ) 4 ](BF 4 ) 2 and one equivalent of the bidentate phosphine dppp to the alternating copolymerization of olefins with CO 4 . Using aprotic solvents as a reaction medium, a relatively long induction period was observed, which was strongly reduced by addition of protic solvents [118a,119].…”

“…Addition of hydrogen also eliminates the induction period [118a]. Running the reaction in methylene chloride in the presence of only small amounts of methanol or water, high molecular weight propylene-CO copolymers can be obtained [120]. The combination of [Pd(NCCH 3 ) 4 ](BF 4 ) 2 with a sterically hindered a-diimine ligand results in an ethylene polymerization catalyst, yielding highly branched amorphous ethylene homopolymers [121].…”

Asymmetric polymerization using C1 resources

“…A 3 1 helical structure has been proposed on the basis of an X-ray investigation of an elastic film of the copolymer at 650% elongation. 50,51 For isotactic poly(styrene-alt-carbon monoxide), a (2/1) helical conformation has been confirmed by powder Xray diffraction for optically pure styrene/CO polyketone. 52,53 A stereocomplex has been suggested to be formed from a racemic mixture of enantiomeric polyketones derived from propene, 1-butene, and allylbenzene with Pd-(S)-Methyl-DUPHOS and its enantiomer on the basis of the melting temperature for the racemic mixture being higher than that for an enantiomerically pure sample.…”

Side-chain liquid-crystalline poly(ketone)s: effect of spacer length, mesogen type and mesogen density on mesomorphic behavior

“…method for the control of molecular weight of poly(propene-alt-CO)s has been introduced by using methanol or water as chain transfer agent. [25,26] This resulted in novel poly(ketone) materials exhibiting the mechanical properties of thermoplastic elastomers. [27] By adding higher 1-alkenes as termonomers both the surface polarity and the glass transition temperature can be tuned.…”