Ti III Compounds

A group of violet titanium(III) acylates has been prepared from TiCl and alkafl carboxylates. AH of the acylates are strong reducing agents similar to TiCl (189). Studies of Ti(III) compounds include the reaction (190)... 

A broad selection of Ti(III) compounds coordinated to a-hydroxy acids, dibotic acids, and 8-hydroxyquinoline has been prepared by the reaction... 

Olefin isomerization is often catalyzed by titanium. An example is the conversion of vinyl norhornene to the comonomer ethylidenenorhornene (141). The catalyst is a mixture of a sodium suspension, AlCl, and (RO)4Ti or Cp2TiCl2. Although isomerization is slow, the yield is high. The active reagent is doubdess a Ti(III) compound. 

Cyclopentadienyltitanium Compounds with Other Carbon Titanium Links. Cyclopentadienyltitanium trichloride and, particularly, Cp2TiCl2 react with RLi or with RAl compounds to form one or more R—Ti bonds. As noted, the Cp groups stabilize the Ti—R bond considerably against thermal decomposition, although the sensitivity to air and moisture remains. Depending on the temperature, mole ratio, and structure of R, reduction of Ti(TV) maybe a serious side reaction, which often has preparative value for Cp/Ti(III) compounds (268,274,275). 

For the Ti(III) compound (ll)2TiCl, prepared in 60% yield from TiCl3(THF)3 and llLi by Y. Qian et al., an intramolecular Ti—O coordination was confirmed by IR spectroscopic data [r(C—O) shift to lower wavenumbers with respect to unchelated analogues], although no spectral details are available. - ... 

In alkaline solution (partly because of the involvement of H in redox equilibrium 22.11, and partly because of the low solubility of the product), Ti(III) compounds liberate H2 from H2O and are oxidized to Ti02. In the absence of air, alkali precipitates hydrous Ti203 from solutions of TiCl3. Dissolution of this oxide in acids gives salts containing [Ti(OH2)s] +, e.g. [Ti(OH2)6]Cl3 and CsTi(S04)2-12H20, the latter being isomorphous with other alums (see Section 13.9). 

There are various Ti(IV) compounds such as phosphates, sulfates, and nitrates as well as various titanates of calcium, iron, and sodium [2]. TiCl4 and the titanates hydrolyze readily to Ti02 Ti(IV) in aqueous solution exists only as hydrated Ti02 species. TiCU is a liquid that is relatively stable in cold water and is used as an intermediate in the production of Ti pigments and in refining Ti metal by reduction of TiCU with Mg. The Ti(III) compound TiCls is a powerful reducing agent useful in synthetic chemistry. 

The heavier metals in group 13 resemble A1 but the tendency to form +1 compounds becomes increasingly significant down the group, so that T1(I) compounds are generally more stable than TI(III) compounds. TI(I) behaves similar to other salts. T1[BF4] is more useful to use than the ammonium complex in nonaqueous media. 

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