Bimetallic salicylaldimine−nickel complexes, bridge{[(2,6-iPr2C6H2)-NCH-(2-anthracenyl-C6H3-O)-κ2-N,O]Ni(η3-CH2Ph)}2 (bridge = ortho-C6H4, 10; bridge = CH2, 11; bridge = ortho-C6H4(C6H4)2,
12), are prepared. The bimetallic complexes 10−12 show higher activities and higher polar monomer
incorporations in the ethylene/2-(methoxycarbonyl)norbornene and ethylene/2-(acetoxymethyl)norbornene
copolymerizations than the mononuclear complex, [(2,6-iPr2C6H3)-NCH-(2-anthracenyl-C6H3-O)-κ2-N,O]Ni(η3-CH2Ph) (13).
The Suzuki-coupling reaction of 2-(dihydroxyboryl)-3,4-dimethyl-2-cyclopenten-1-one and 2-(dihydroxyboryl)-3-methyl-2-cyclopenten-1-one with 2-bromoaniline derivatives affords cyclopentenone compounds from which cyclopentadiene compounds, 4,6-R'(2)-2-(2,5-Me2C5H3)C6H2NH2 and 4,6-R'(2)-2-(2,3,5-Me3C5H2)C6H2NH2 are prepared. After sulfonation of the -NH2 group with p-TsCl, metallation is carried out by successive addition of Ti(NMe2)4 and Me2SiCl2 affording o-phenylene-bridged Cp/sulfonamido titanium dichloride complexes, [4,6-R'(2)-2-(2,5-Me2C5H2)C6H2NSO2C6H4CH3)]TiCl2 (R'=H, ; R'=Me, ; R'=F, ) and [4,6-R'(2)-2-(2,3,5-Me3C5H)C6H2NSO2C6H4CH3)]TiCl2 (R'=H, ; R'=Me, ; R'=F, ). The molecular structures of and [2-(2,5-Me2C5H2)C6H4NSO2C6H4CH3)]Ti(NMe2)2 are determined by X-ray crystallography. The Cp(centroid)-Ti-N angle in is smaller (100.90 degrees) than that observed for the CGC (constrained-geometry catalyst), [Me2Si(eta5-Me4Cp)(NtBu)]TiCl2 (107.6 degrees) indicating a more "constrained feature" in than in the CGC. Complex shows the highest activity among the newly prepared complexes in ethylene/1-octene copolymerization but it is slightly inferior to the CGC in terms of activity, comonomer-incorporation ability, and molecular weight of the obtained polymers.
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