Biscyclopentadienyltitanium

This can be circumvented by choosing alkyl groups with no P H, eg, methyl, neopentyl, trimethylsilylmethyl, phenyl and other aryl groups, and benzyl. The linear transition state for -elimination can also be made stericaHy impossible. The most successful technique for stabilization combines both principles. The pentahaptocyclopentadienyl ring anion (Cp) has six TT-electrons available to share with titanium. Biscyclopentadienyltitanium dichloride... 

Long (81) showed that the complex from biscyclopentadienyltitanium dichloride and methylaluminum chloride or a simply derived product from it, was an active ethylene polymerization catalyst. There have been a number of attempts to determine the exact nature of initiation in polyethylene. However, by any techniques available until now, it has not been possible to determine the actual ionic nature of the active catalyst which polymerizes ethylene. Karapinka and Carrick (82) studied the polymerization of ethylene with biscyclopentadienyltitanium dichloride and various alkylaluminum compounds. They found that the alkyl group exchanged so readily between the aluminum and titanium, that the location of the initiating site could not be determined. All that could be concluded was that an ethyl group initiated the polymerization more easily than the phenyl. 

Biscyclopentadienyltitanium Compounds and Aluminumalkyl as Catalysts for the Polymerization of Ethylene... 

The chemistry of transition metal carbene complexes has been examined with an eye to applications in organic synthesis ever since their discovery by Fischer in 1964, and the growth in the number of useful applications has been exponential with tirne. " There are two types of transition metal carbene complexes those which have electrophilic carbene carbons and which are typified by the pentacarbonylchro-mium complex (1), and those which have nucleophilic carbene carbons and which are typified by the biscyclopentadienyltitanium complex (2). Complexes (1) and (2) are often referred to as carbene and alkylidene complexes, respectively. This review will be limited to the chemistry of electrophilic carbene complexes of the Fischer type. The chemistry of the nucleophilic alkylidene complexes will be covered in Chapter 9.3, this volume. ... 

Substitution of one of the alkyl groups of Ti( y -C5H5)2R2 by halide increases stability of the acyl derivatives by suppressing the reductive elimination path. Thus, the biscyclopentadienyltitanium(IV) derivatives Ti(j7 -C5H5)2R(X) react with CO to give isolable acyl derivatives ... 

We recently synthesized the interfacial condensation product of biscyclopentadienyltitanium IV dichloride, Cp2TiCl2, and the disodium salt of squaric acid. 

The following chemicals were utilized as received from Aldrich, Milwaukee, Wis. Biscyclopentadienyltitanium dichloride (1271-19-8) and 3,4-dihydroxy-3-cyclobutene-1,2-dione, (99%-2892-51-5). Polycondensation was effected in a one quart Kimex emulsifying jar placed on a Waring Blendor (Model 1120) with a no-load speed of about 18,000 rpm (120 volts). 

Amylose has been modified through the interfacial condensation with biscyclopentadienyltitanium dichloride employing various mixing procedures. The product contains largely glucose units with one titanocene moiety connected throughtlie ring hydroxyls. The properties of these modified amylose derivatives and their potential applications are discussed,... 

Prior work has focused on the use of tin-containing modified polysaccharides as additives and materials that utilize the biological inhibitory properties of the organostannanes. The present study involves the use of biscyclopentadienyltitanium dichloride (titanocene dichloride) as the metal-containing moiety,... 

Bis (cyclopentadienyl) chromium II. See Bis (cyclopentadienyl) chromium Bis (cyclopentadienyl) cobalt. See Cobaltocene Bis (cyclopentadienyl) dichlorotitanium. See Titanocene dichloride Biscyclopentadienyliron. See Ferrocene Biscyclopentadienyltitanium dichloride Biscyclopentadienyltitanium (IV) dichloride. See Titanocene dichloride Bis (cyclopentadienyl) vanadium dichloride CAS 12083-48-6 EINECS/ELINCS 235-150-8 UN 8027... 

Synonyms Bis (cyclopentadienyl) dichIorotitaniurn Biscyclopentadienyltitanium dichloride Biscyclopentadienyltitanium (IV) dichloride Dichlorobis (1,3-cyclopentadiene) titanium Dichlorobiscyclopentadienyl titanium Dichlorodicyclopentadienyltitanium (Dichlorodi-pi-cyclopentadienyltitanium Dichlorotitanocene Dicyclopentadienyidichlorotitanium Dicyclopentadienyltitanium dichloride Titanium, dichloro-di-pi-cyclopentadienyl- Titanium ferrocene Titanocene Titanocene dichloride... 

The polymerization of olefins, promoted by homogeneous Ziegler catalysts based on biscyclopentadienyltitanium(IV) or analogous compounds and aluminum alkyls, is accompanied by a series of other reactions that greatly complicate the kinetic interpretation of the polymerization process ... 

Although the direct generation of titanium enolates is typically the most useful method of generating titanium enolates for aldol reactions, other methods have been described. Grubbs and Stille reported that titanium enolates could be generated by reaction of biscyclopentadienyltitanium al-kylidene complexes and acyl halides [93]. Oshima and coworkers reported the formation of titanium enolates from a-iodoketones with allylsilane and titanium tetrachloride [94]. Mukaiyama and coworkers reported the generation of titanium enolates from a-bromoketones on treatment with TiCh and copper powder [95]. 

Biscyclopentadienyltitanium dichloride (Aldrich, Milwaukee, VI), biscyclopentadienylzirconium dichloride (Aldrich, Milwaukee, VI), bis-cyclopentadienylhafnium dichloride (Alfa, Danvers) dextran (molecular weight 2 to 3 X 10°, United States Biochemical Corporation, Cleveland, OH) dibutyltin dichloride (Fisher, Fairlawn, NJ) diphenyltin dichloride (Metallomer Labs., Maynard, MA) diethyltin dichloride (Ventron-Alfa Inorganics, Beverly, MA) tri-n-butyltin chloride (Alfa) tri-n-propyltin chloride (Alfa) tri-n-butyltin chloride (Aldrich, Milwaukee, VI) di-octyltin dichloride (Alfa) dilauryltin dichloride (Metallomer) di-methyltin dichloride (Alfa) tricyclohexyltin bromide (Alfa) triethyl-amine (Eastman) piperdine (Matheson, Coleman and Bell, Cincinnati, OH) N,N-dimethylaniline (Fisher) 3,5-latidine (Aldrich) and pyridine (J. T. Baker Chemical Co., Phillipsburg, NJ) were used as received. 

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