- Synthesis, characterization and catalytic activity of the complex titanium bis(dimethylmalonate)-bis(diethylamido) in the polymerization of propylene
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In this account we present the synthesis, characterization and catalytic activity in the polymerization of propylene of a bis(dimethyl malonate) titanium bis(diethylamine) complex (1). The complex exhibits in solution a dynamical isomerization following an internal Bailar twist. The activation of complex 1 was obtained by its reaction with methylalumoxane (MAO). The activated complex in solution shows a different dynamic process involving an equilibrium between a monodentate η1 and bidentate η2 binding of the dimethylmalonate ligand to the metal center. This equilibrium is responsible for the formation of, at least, two active species for the polymerization reaction bearing major symmetry differences. The monodentate coordination (opened form) of the ligand was found to be the major form of the active species of the complex when activated with MAO, most probably due to a strong interaction of the oxygen atoms in the ligand with the strong Lewis acid co-catalyst. The active species in the polymerization were studied by NMR and ESR spectroscopies. The resulting polypropylene showed elastomeric properties with low tacticites.
- Gueta-Neyroud, Tal,Tumanskii, Boris,Botoshansky, Mark,Eisen, Moris S.
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- PROCESSES FOR PRODUCING TRANSITION METAL AMIDES
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Processes are provided for producing transition metal amides. In methods according to this invention, at least a halogenated transition metal and an amine are combined in a solvent to produce an intermediate composition and an alkylated metal or a Grignard reagent is added to the intermediate composition to produce the transition metal amide.
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Page/Page column 2-3
(2011/02/18)
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- PROCESSES FOR PRODUCING TRANSITION METAL AMIDO AND IMIDO COMPOUNDS
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Processes are provided for producing transition metal amidos and/or imidos. In methods according to this invention, at least one halogenated transition metal, an amine compound and a solvent are combined, followed by the addition of an alkylated metal or a Grignard reagent to produce the transition metal amide and/or imido.
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Page/Page column 7-8
(2009/10/21)
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- Exploring alternative synthetic routes for the preparation of five-coordinate diamidoamine group 4 metal complexes
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Efficient synthetic routes for the preparation of electrophilic titanium and zirconium complexes featuring a tridentate diamidoamine ligand have been developed. The five-coordinate titanium dichloride complexes [(MesNCH 2CH2)2NR]TiCl2 (R = H (3), SiMe 3 (4)) are conveniently prepared from the amine elimination reactions of the triamines (MesNHCH2CH2)2NR (R = H (1), SiMe3 (2)) with Ti(NEt2)2Cl2. Treatment of Ti(NEt2)4 with 2 equiv of SiMe3Cl offers an effective method for the preparation of Ti(NEt2) 2Cl2. The corresponding five-coordinate zirconium homologues [(MesNCH2CH2)2NR]ZrCl2 (R = H (5), SiMe3 (6)) are synthesized via the toluene elimination reactions of Zr(benzyl)2Cl2(Et2O)2 with 1 and 2, respectively. The thermally unstable and photosensitive Zr(benzvl)2Cl2(Et2O)2 species may be prepared in situ from the reaction of Zr(benzyl)4 with 2 equiv of [NEt3H]Cl in diethyl ether at 0°C in the dark. The toluene elimination reaction of Hf(benzyl)4 with 1 affords the dibenzyl Hf complex [(MesNCH2CH2)2NH]Hf(benzyl) 2, 7. The X-ray structural and solution NMR data for 4, 5, 6, and 7 reveal that these electrophilic group 4 metal complexes adopt the facial structure with either a chloride or a η2-benzyl ligand trans to the central amino N atom of the tridentate diamidoamine ligand.
- Morgan, Alicia R.,Kloskowski, Michael,Kalischewski, Felix,Phillips, Aaron H.,Petersen, Jeffrey L.
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p. 5383 - 5392
(2008/10/09)
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- Dihydrocarbylamino metal compounds
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This invention provides a process of preparing dihydrocarbylamido metal compounds. This process comprises bringing together, in a liquid reaction medium, at least one metal halide, MX4, where M is titanium, zirconium, or hafnium, and X is a halogen atom, with at least one dihydrocarbylamine, such that a mixture of (i) halometal amides in which the atom ratio of halogen to metal is greater than about 0.1 and less than about 2, and (ii) dihydrocarbylamine hydrohalide is produced. Then (i) and (ii) are separated from each other, and (i) is brought together with an alkali metal amide, ANR2, where A is an alkali metal, and R is a hydrocarbyl group, in a liquid medium, to produce a product comprised of substantially halogen-free dihydrocarbylamido metal compound. This invention further provides for purifying dihydrocarbylamido metal compounds by contact with a nitrile.
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Page/Page column 8-12
(2008/06/13)
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- Homogeneous catalysts and olefin polymerization process
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Olefins are polymerized in the presence of a homogeneous catalyst represented by the formula LTi(NR2)3 wherein L is a II -bonded ligand selected from the group consisting of indenyl, C1 -C4 alkyl substituted indenyl, --OSiR3 substituted indenyl, R is a C1 -C4 alkyl group wherein each R attached to the same nitrogen atom is the same, but the R groups attached to different nitrogen atoms can be the same or different from those attached to the other nitrogen atoms.
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- New titanatranes and an unexpected reactivity trend in (dialkylamido)titanatranes
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The relative rates of displacement of the NR2 group in (dialkylamido)titanatranes R2NTi(OCH2CH2)3N by -OH and -SH compounds is in the order NEt2 ? NMe2 > N(i-Pr)2. This unanticipated order is rationalized on the postulated prior formation of HR2N+Ti(OCH2CH2)3N (A), which facilitates departure of R2NH upon subsequent nucleophilic attack. For R = Et and i-Pr, the concentration of A is higher than for R = Me, owing to the basicity order Et2N ? (i-Pr)2N > Me2N. The greater reactivity of A where R = Me relative to R = i-Pr is attributed to the greater steric protection from nucleophilic attack on the metal afforded by the H(i-Pr)2N+ group. The faster reactions of CF3CH2OH and PhOH compared with their sterically similar but more weakly acidic analogues CH3CH2OH and i-PrOH, respectively, support this hypothesis as do the comparable displacement rates of Et2N and Me2N in the presence of the strong nonnucleophilic base P(MeNCH2CH2)3N and the reactions of 4 and 14 with HBF4 and NH4Cl but not with NaBF4 or Me4NCl. New titariatranyl derivatives reported include five arylates, two thioarylates, and four diolates. The X-ray parameters for [i-PrSTi(OCH2CH2)3N]2 are as follows: triclinic, space group P1 (No. 2), a = 7.434(5) ?, b = 12.540(3) ?, c = 7.034(3) ?, α = 105.72(3)°, β = 98.87(3)°, γ = 85.30(4)°, and Z = 1. For [Me2COTi(OCH2CH2)3N]2 these parameters are as follows: monoclinic, space group P21/n (No. 14), a = 6.6590(6) ?, b = 17.819(2) ?, c = 10.095(1) ?, and β = 107.975(9)°.
- Naiini,Ringrose,Su,Jacobson,Verkade
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p. 1290 - 1296
(2008/10/08)
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