Organometallic Titanium iv Compounds

Organometallic Titanium(iv) Compounds.—As in earlier volumes only selected aspects of this chemistry are presented. 

This chapter attempts to summarize the literature on this class of complexes from the publication of COMC (1995) to 2004 or early 2005. Synthesis, structure, and chemical properties of organometallic titanium(iv) compounds, which contain different types of Ti-C bonds supported by additional ligands, will be covered. We attempt to highlight the major developments from 1993 and tentatively to reveal new trends in this field over the next few years. 

Organometallic compounds, 14 550-551 25 71. See also Organometallics carbides contrasted, 4 648 as initiators, 14 256-257 iridium, 19 649-650 molybdenum(III), 17 27 osmium, 19 642-643 palladium, 19 652 platinum, 19 656-657 reaction with carbonyl groups, 10 505-506 rhodium, 19 645-646 ruthenium, 19 639 sodium in manufacture of, 22 777 titanium(IV), 25 105-120 Organometallic fullerene derivatives,... 

The low-pressure polymerization of olefins using Ziegler-Natta catalysts, i.e., mixtures of compounds of transition groups IV to VI of the periodic table of the elements together with organometallic compounds of groups I to III is widely applied. Such catalysts, consist of titanium alkyl compounds and aluminum alkyl compounds or alkylaluminum halides. 

Agapie, T. Diaconescu, P. L. Mindiola, D. J. Cummins, C. C. Radical sdssion of symmetrical 1,4-dicarbonyl compounds C-C bond cleavage with titanium(IV) enolate formation and related reactions. Organometallics 2002,... 

Organometallic Compounds. Several trifluoromethyl organometallic complexes have been preparedby halogen-CF3 exchange mediated by TMSCF3. Those include titanium(IV), ... 

Ziegler-Natta Catalysts (Heterogeneous). These systems consist of a combination of a transition metal compound from groups IV to VIII and an organometallic compound of a group I—III metal.23 The transition metal compound is called the catalyst and the organometallic compound the cocatalyst. Typically the catalyst is a halide or oxyhalide of titanium, chromium, vanadium, zirconium, or molybdenum. The cocatalyst is often an alkyl, aryl, or halide of aluminum, lithium, zinc, tin, cadmium, magnesium, or beryllium.24 One of the most important catalyst systems is the titanium trihalides or tetra-halides combined with a trialkylaluminum compound. 

In the broadest sense, Ziegler Natta catalysts may be regarded as combinations of Group IV-VIII transition metal compounds with Group I-III organometallics which can effect polymerization of olefins and dienes under relatively mild conditions of temperature and pressure [82,83]. Titanium compounds and aluminum alkyls are used most frequently in commercial polyolefin processes. Both titanium and vanadium compounds are used in conjunction with aluminum alkyls in catalyst systems for synthetic rubber/elastomers. 

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