RESUMO
Bimetallic dichlorotitanium complexes, {2,6-[eta(5)-2,5-Me2C5H2](2)-4-R-C6H2N-microN}{Ti(IV)Cl2}2 (, R=Me; , R=F) and 4,4'-A[{2-(eta(5)-2,3,5-Me3C5H)C6H3NC6H11-kappaN}Ti(IV)Cl2]2 (, A=CH2; , A=O; , A=ortho-C6H4) are prepared via a key step of the Suzuki-coupling reaction of 2-dihydroxyboryl-3-methyl-2-cyclopenten-1-one () with dibromo-compounds. The solid state structure of was determined by X-ray crystallography. Complexes and are not active for ethylene/1-hexene copolymerization. Meanwhile, the complexes are highly active and their activities are higher than that of the mononuclear analogue, {2-(eta(5)-2,3,5-Me3C5H)C6H3NC6H11-kappaN}Ti(IV)Cl2 (). The molecular weights of the polymers obtained with the bimetallic complexes are higher than that of the polymer obtained using . Slightly higher contents of long-chain-branching are observed for the copolymers obtained using the bimetallic system.
Assuntos
Alcenos/química , Amidas/química , Derivados de Benzeno/química , Reagentes de Ligações Cruzadas/química , Polímeros/química , Titânio/química , Catálise , Cristalografia por Raios X , Etilenos/química , Modelos Moleculares , Estrutura Molecular , Temperatura , ViscosidadeRESUMO
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.