1026786-18-4Relevant articles and documents
Neutral bimetallic nickel(II) phenoxyiminato catalysts for highly branched polyethylenes and ethylene-norbornene copolymerizations
Rodriguez, Brandon A.,Delferro, Massimiliano,Marks, Tobin J.
, p. 2166 - 2168 (2008)
The synthesis and characterization of novel bimetallic, neutrally charged dinickel 2,7-diimino-1,8-dioxynaphthalene polymerization catalysts is reported. Ethylene polymerizations as well as ethylene-co-norbornene copolymerizations display increased cataly
Bimetallic effects for enhanced polar comonomer enchainment selectivity in catalytic ethylene polymerization
Rodriguez, Brandon A.,Delferro, Massimiliano,Marks, Tobin J.
, p. 5902 - 5919 (2009/09/25)
The synthesis and characterization of the bimetallic 2,7-di-[(2,6- diisopropylphenyl)imino]-1,8- naphthalenediolato group 10 metal polymerization catalysts {[Ni(CH 3)] 2[1,8-(O) 2C 10H 4-2,7-[CH=N(2,6- Pr 2C 6H 3)](PMe 3) 2} and {[Ni(1-naphthyl)] 2[1,8-(O) 2C 10H 4-2,7-[CH=N(2,6-Pr 2C 6H 3)](PPh 3) 2} [FI 2-Ni 2(PR 3) 2] are presented, along with the synthesis and characterization of the mononuclear analogues {Ni(CH 3)[3- tBu- 2-(0)C 6H 3CH=N(2,6- iPr 2C 6H 3)](PMe) 3}and{Ni(1-naphthyl)[3- tBu-2-(0)C 6H 3CH=N(2,6- iPr 2C 6H 3)](PPh) 3}[FI- Ni (PR 3)].Monometallic Ni catalysts were also prepared by functionalizing one lig ation center of the bimetallic ligand with a trimethylsilyl group (TMS),yielding {Ni(CH 3)[1,8-(O)(TMSO)C 10H 4-2,7-[CH=N(2,6- iPr 2C 6H 3)](PMe 3)} [TMS-FI 2-Ni(PMe 3)]. The Fl2-Ni 2 catalysts exhibit significant increases in ethylene homopolymerization activity versus the monometallic analogues, as well as increased branching and methyl branch selectivity, even in t he absence of a Ni(cod) 2 cocatalyst. Increasing ethylene concentrations significantly suppress branching and alter branch morphology. FI 2-Ni 2-mediated copolymerizations with ethylene + polar-functionalized norbornenes exhibit a 4-fold increase in comonomer incorporation versus Fl-Ni, yielding copolymers with up to 10percent norbornene copolymer incorporation. FI 2-Ni 2-catalyzed copolymerizations with ethylene + methylacrylate or methyl methacrylate incorporate up to 11percent acrylate comonomer, while the corresponding mononuclear Fl-Ni catalysts incorporate negligible amounts. Furthermore, the FI 2-Ni 2-mediated polymerizations exhibit appreciable polar solvent tolerance, turning over in the presence of ethyl ether, acetone, and even water. The mechanism by which the present cooperative effects take place is investigated, as is the nature of the copolymer microstructures produced.
