Titanium complexes with indenyls

Bis(cyclopentadienyl) titanium complexes with imido groups, 4, 419-420 with indenyls, 4, 428... 

Ind-amido titanium complexes with o -alkenyl functions in position 2 of the indenyl ring have been synthesized and characterized. After activation with MAO, these complexes were used as homogeneous and heterogeneous catalysts for the homopolymerization of ethylene and propylene and the co-polymerization of ethylene and 1,7-octadiene.406 A series of alkyl-, u -alkenyl-, and u -phenylalkyl-substituted Cp- and Ind-amido dichloro titanium complexes have been synthesized and characterized. The cj-phenylalkyl-substituted complexes react with LiBu to give metallacycles via a CH activation reaction on the ortho-position of the phenyl group (Scheme 305).741 742 After activation with MAO, these complexes catalyze ethylene polymerizations. The substituents on the aromatic system influence the polymerization activity of the catalysts and the properties of the polyethylene. The u -alkenyl-substituted catalysts show self-immobilization in ethylene polymerization. 

In 1985, Ishihara [10] at Indemitsu, Japan, reported that monocyclopentadienyl, indenyl, or fluorenyl titanium complexes, with different substituents on the Cp derivatives, were highly active for styrene polymerization, producing syndiotactic polystyrene with high melting temperature. Ishihara smdied early transition metals from group 3 or 4 systems based on late transition metals such as Ni were inactive for styrene homo- or copolymerization. Monocyclopentadienyl complexes, also... 

Reactions of aldehydes with complexes 13—17 provide optically active homoallylic alcohols. The enantioselectivities proved to be modest for 13—16 (20—45% ee). In contrast, they are very high (> 94% ee) for the (ansa-bis(indenyl))(r]3-allyl)titanium complex 17 [32], irrespective of the aldehyde structure, but only for the major anti diastereomers, the syn diastereomers exhibiting a lower level of ee (13—46% ee). Complex 17 also gives high chiral induction (> 94% ee) in the reaction with C02 [32], in contrast to complex 12 (R = Me 11 % ee R = H 19% ee) [15]. Although the aforementioned studies of enan-... 

Asymmetric isomerization of 4-terr-butyl-l -vinylcyclohexane (6) catalyzed by bis(indenyl)-titanium complex (8) bearing a chiral bridging moiety afforded (S)-4-fcrr-buty 1-1 -ethy lidenecy-clohexane (7) with up to 80% ee (Scheme 3A.3).3,4... 

An asymmetric variant of double-bond isomerization could be achieved with the chiral a ra-bis(indenyl)titanium complex [43]. After activation with LiAlH4 it isomerizes m 50,traw5-4-tert-butyl-l-vinyl-cyclohexane to the 5-alkene with remarkable enantioselectivity (80 % ee). 

It has been established that the replacement of Cp with an indenyl or fluorenyl ligand has important effects on the catalytic properties of these type of complexes. Monoindenyl and monofluorenyl titanium complexes can generally be prepared by employing dehalosilylation (or analogous dehalostannylation) (Scheme 172), and several such complexes have been described. 

The synthesis of the Ind-amido titanium complexes [(C9H5R)SiMe2NBut]TiX2 (Scheme 304) with alkoxo and amido substituents at 2- and 3-indenyl position has been reported and the molecular structures of the derivatives for R = NMe2 and N(CH2)4 have been determined by X-ray diffraction. The methyl derivatives are activated with B(C6F5)3 and studied as catalytic systems for the ethylene/l-octene co-polymerization. A dramatic effect of the indenyl substituent nature on catalyst efficiency and polymer properties is observed.740... 

The reaction of the amido complex (CsH4CH2CH2NPr 2)Ti(NMe2)3 with 3 equiv. of isopropanol affords the tris-alkoxo compound (C5H4CH2CH2NPr 2)Ti(OPr )3.374 A series of aminoalkyl-substituted mono-Cp trichloro, triiso-propoxo, and mono(indenyl) triisopropoxo titanium complexes that contain pyridyl (2-picolyl), diisopropylaminoethyl and dimethylaminoethyl, and phenylethyl pendant arms have been prepared (Scheme 159 Section 4.05.3.1.l.(iii)). The utility of these complexes for the polymerization of ethylene, propylene, and styrene has been investigated.332... 

Titanium complexes derived from ethylene-bridged 2-indenyl ligands (Scheme 650) have been prepared by reductive dehydroxy coupling of 2-(hydroxymethyl)indenes with low-valent titanium compounds. Alkyl substitution of the indene ring at C(3) improves the regioselectivity of the reductive coupling.1671... 

The first isospecific propene polymerization with an ethanediyl-bridged bis (indenyl)-titanium complex demonstrated in 1983 the capability of ansa-metaUocenes to control the tacticity of a growing polypropylene chain [4, 48], thus creating a strong interest in exploring the potential use of ansa-metallocenes for industrial polypropylene production. A first step towards industrially suitable systems was the use of much more stable zirconium complexes, which when activated by the methylaluminoxane co-catalyst [3] allowed higher polymerization temperatures and thus higher activities [5]. 

After treatment with the indenyl and tetrahydroindenyl titanium complexes XXXV-XXXVII and the mono(cyclopentadienyl) titanium derivatives XXXVIII-XL phenomena comparable with those observed after application of substituted titanocene derivatives occurred. When only one cyclopentadienyl ring was exchanged by the equally Ti -bound tetrahydroindenyl ligand (XXXVI), the optimum cure rate amounted to 73% whereas, in the case of the bis(indenyl) and bis(tetrahydro-... 

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