Organometallic compounds containing titanium

The ethylene polymerization was observed (9a) also in the presence of c-organometallic compounds of titanium and zirconium, containing such ligands as -CH i(CH3) , -CH(C H6)Si(CH3)3, -CH2C(CH3)3,... 

Specialist Periodical Reports of the Chemical Society (Condon), Organometallic Compounds, contain numerous references on titanium compounds which can be located through the volume indexes. 

Reactions with BucNC lead to new organometallic compounds containing an 72-C,N-bound cyclopentadiene imine, which was structurally characterized as a pyridine adduct (Scheme 118). Reactions with benzonitrile lead to the elimination of 1 equiv. of the corresponding pyridine and formation of the dimeric titanium derivative (ArO)2Ti(/x-PhCN)2Ti(OAr)2 containing two bridging benzonitrile ligands. The compound has been structurally characterized... 

Organometallic compounds containing bonds between carbons and metals provide a source of nucleophilic carbon atoms which can react with electrophilic carbon to form a new carbon-carbon bond (Banach et al., 2001 Finelli et al., 2004). Organometallics find practical uses in catalytic processes. For example. Titanium tetrabutoxide, Butylhydroxyoxo-stannane are well-known catalysts for the esterification between diacid and diol in polyester industry (Grzesik et al., 2000 Prabhakarn et al., 2011). The catalytic mechanism and kinetic model of related catalysts are reviewed in the following discussions. 

Recently some information became available on a new type of highly active one-component ethylene polymerization catalyst. This catalyst is prepared by supporting organometallic compounds of transition metals containing different types of organic ligands [e.g. benzyl compounds of titanium and zirconium 9a, 132), 7r-allyl compounds of various transition metals 8, 9a, 133), 7r-arene 134, 185) and 71-cyclopentadienyl 9, 136) complexes of chromium]. 

There has been no recent comprehensive review of this area, although a book on the organometallic chemistry of titanium, zirconium, and hafnium deals, in part, with some of the hydride derivatives (1). In the present review, the first part of the discussion reflects the fact that much of the early work on organotitanium hydrides was, often unknowingly at the time, interwoven with attempts to prepare titanocene, Cp2Ti (Cp = tj3-C5H5). Subsequent sections deal with similar compounds containing an additional metal (e.g., aluminum), miscellaneous titanium hydride compounds, and a summary of the main properties of the above species. 

A number of stereospecific non-enzyme catalysts have been developed that convert achiral substrates into chiral products. These catalysts are usually either complex organic (Figure 10.8(a)) or organometallic compounds (Figure 10.8(b)). The organometallic catalysts are usually optically active complexes whose structures usually contain one or more chiral ligands. An exception is the Sharpless-Katsuki epoxidation, which uses a mixture of an achiral titanium complex and an enantiomer of diethyl tartrate (Figure 10.8(c)). 

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. 

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