title: Catalytic ethylene polymerisation in carbon dioxide as a reaction medium with soluble nickel(II) catalysts.
abstract: A series of neutral Ni(II)-salicylaldiminato complexes substituted with perfluorooctyl- and trifluoromethyl groups, [Ni{kappa(2)-N,O-6-C(H)==NAr-2,4-R'(2)C(6)H(2)O}(Me)(pyridine)] (6 a: Ar=2,6-{4-(F(17)C(8))C(6)H(4)}(2)C(6)H(3), R'=I; 6 b: Ar=2,6-{4-(F(3)C)C(6)H(4)}(2)C(6)H(3), R'=I; 6 c: Ar=2,6-{3,5-(F(3)C)(2)C(6)H(3)}(2)C(6)H(3), R'=3,5-(F(3)C)(2)C(6)H(3); 6 d: Ar=2,6-{4-(F(17)C(8))C(6)H(4)}(2)C(6)H(3), R'=3,5-(F(3)C)(2)C(6)H(3); 6 e: Ar=2,6-{3,5-(F(3)C)(2)C(6)H(3)}(2)C(6)H(3), R'=I) were studied as catalyst precursors for ethylene polymerisation in supercritical CO(2). Catalyst precursors 6 a and 6 c, which are soluble in scCO(2), afford the highest polymer yields, corresponding to 2 x 10(3) turnovers. Semicrystalline polyethylene (M(n) typically 10(4) g mol(-1)) is obtained with variable degrees of branching (11 to 24 branches per 1000 carbon atoms, predominantly Me branches) and crystallinities (54 to 21 %), depending on the substitution pattern of the catalyst.
authors.affiliation: Universität Konstanz, Lehrstuhl für Chemische Materialwissenschaft, Fachbereich Chemie, Universitätsstr. 10, 78457 Konstanz, Germany.
authors.forename: Amaia
authors.initials: A
authors.lastname: Bastero
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Franciò
authors.forename: Walter
authors.initials: W
authors.lastname: Leitner
authors.forename: Stefan
authors.initials: S
authors.lastname: Mecking
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D002384:Catalysis; D005030:Ethylenes / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D005030:Ethylenes; D009942:Organometallic Compounds; D002245:Carbon Dioxide; D009532:Nickel; C036216:ethylene