Generation of homogeneous (sp(3)-C(1))-bridged Cp/amido and Cp/phosphido group 4 metal Ziegler-Natta catalyst systems

Synthesis of ultrahigh-molecular-weight ethylene/1-octene copolymers with salalen titanium(iv) complexes activated by methyaluminoxane

Two salalen titanium(iv) complexes ((H-salalen)TiCl2 and (F-salalen)TiCl2) containing hydrogen and fluorine respectively on the phenolate ring close to the imine were synthesized for the copolymerization of ethylene with 1-octene to prepare poly(ethylene-co-1-octene) in the presence of methylaluminoxane (MAO). The (F-salalen)TiCl2/MAO showed higher catalytic activity and better copolymer characteristics such as a higher molecular weight, narrower molecular weight distribution, and higher 1-octene incorporation than (H-salalen)TiCl2/MAO, which revealed that the electron-withdrawing conjugated effect introduced by fluorine substituents led to improvements on catalytic performance and thermal stability. The influences of copolymerization conditions including temperature, Al/Ti molar ratios and comonomer feed ratios on the copolymerization behavior of (F-salalen)TiCl2/MAO and the copolymer microstructure were investigated in detail. Under the activation of MAO, the (F-salalen)TiCl2 could produce ultrahigh molecular weight poly(ethylene-co-1-octene) with 1-octene incorporation ratios in the range of 0.9-3.1 mol% and exhibit relatively high activity. It could be inferred that long ethylene sequences in the copolymer were segregated by the isolated 1-octene units based on the 13C NMR characterization of the copolymer. Moreover, the thermal properties and crystallization of copolymers were determined by DSC and XRD and correlated to the ethylene sequence length distribution. The reactivity ratios calculated by the triad distribution in 13C NMR revealed the random comonomer distribution in the copolymer chain.

Synthesis and characterization of manganese(ii) complexes supported by cyclopentadienyl-phosphine ligands

A series of manganese(ii) complexes supported by cyclopentadienyl-phosphine ligands have been synthesized and characterized. [LMn(μ-Cl)]₂ served as a precursor to organomanganese(ii) derivatives.

Synthesis of sp3C1-Bridged Constrained Geometry Complexes and their Application for Copolymerization of Ethylene and 1-Octene

Novel sp3C1-bridged constrained geometry complexe(CGC) were synthesized, and fulvene was used as initial stuff, they were characterized by 1H-NMR, 13C NMR, MS and EA. The CGC/methylaluminoxane (MAO) system show activation for copolymerization of ethylene and 1-octene under 1.0 atmospheric pressure (Complex 2/MAO, 1.196 × 106 g-Polymer /mol-Zr•h, Pethylene = 1.0 atm, Al/Zr = 1000, time = 30 min,1-Octene content in polymer = 5.46 mol%).

{2-[(η-Cyclo-penta-dien-yl)diphenyl-meth-yl]-1H-imidazolido-κN}bis-(N,N-diethyl-amido)-titanium(IV)

The chemically achiral title mol-ecule, [Ti(C(4)H(10)N)(2)(C(21)H(16)N(2))], crystallizes in the chiral space group P2(1). All three N atoms coordinating to the Ti(IV) atom adopt planar environments [sums of valence angles = 359.5 (6), 360.0 (7) and 360.0 (6)°], which is indicative of pπ-dπ donation from all of these N atoms to the metal and, thus, of the formal 18 e(-) nature of the complex. The overall coordination about the Ti(IV) atom is distorted tetra-hedral, assuming the cyclo-penta-dienyl ring occupies one coordination site. The Ti-N(imidazole) amide-type bond is longer by approximately 0.16 Å than the other two Ti-N(amide) bonds.

o-Phenylene-bridged Cp/sulfonamido titanium complexes for ethylene/1-octene copolymerization

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.