Titanium aryloxides

Titanium anodes, 15 591 Titanium aryloxides, 25 78 Titanium beach-sand mining, 24 847 Titanium borides, 25 5-6 physical properties of, 25 7 Titanium bromide... 

An alternative reaction, the addition of an olefinic C—H bond to C=0, is catalyzed by Lewis acidic titanium aryloxide complexes chiral binaphthol ligands give high optical yields.96... 

Eirth VA, Stephan WD. Monocyclopentadienyl—titanium aryloxide sulfide eomplexes. Inorg Chem 1998 37(18) 4726-31. 

Gupta, R., Singh, A., Mehrotra, R. C. Synthesis, characterization and reactions of some titanium aryloxides. Indian J. Chem., 29A, 596-598 (1990). 

Subsequently, direct incorporation of GO by titanocene(ii) catalyst, Gp2Ti(GO)2, under a GO atmosphere was reported.This catalytic system showed substantially higher TON and broader functional group compatibility. However, this catalyst fails to react with sterically hindered olefins and alkynes. In a recent contribution from the same group, a series of aryloxide titanium complexes 22 (figure 4) are prepared and shown to promote PKR with some sterically hindered enynes." ... 

Figure 4 The precursor of titanium-based catalyst bearing aryloxide.

The monomeric three-coordinate aryloxides of scandium171 and titanium,172 M(OAr )3 (OAr = 2,6-dw-butylphenoxide), have been reported. The electronic and ESR spectra of deep blue Ti(OAr )3 are consistent with a trigonal planar geometry and a strong Ti(OAr ) ion was observed... 

Titanium tetra- n- decyloxide Titanium tetr a-is o o ctylo xid e Titanium tetra-isobomyloxi de [84215-64-5] Ti(OC10H21)4 Ti(OC8H17)4 Ti(OC10H17)4 68 Aryloxides 26527 23513... 

Hydrolysis and Condensation. The rate of hydrolysis of the tetraalkyl titanates is governed by the nature of the alkoxy groups. The lower titanium alkoxides, with the exception of tetramethyl titanate [992-92-7], are rapidly hydrolyzed by moist air or water, giving a series of condensed titanoxanes, (Ti— O—Ti— O—) (17). As the chain length of the alkyl group increases, the rate of hydrolysis decreases. Titanium methoxides, aryloxides, and C-10 and higher alkyl titanates are hydrolyzed much more slowly. 

Consequently, various Grignard reagents have been shown to be effective for the intramolecular cyclopropanation reactions with insignificant differences in yields. Whereas several titanium alkoxides and aryloxides can also be employed, chlorotitanium triisopropoxide and methyltitanium triisopropoxide have often been found to be the titanium reagent of choice. Ether, THE, toluene, or even dichloromethane are generally appropriate reaction solvents. 

The unsubstituted para-t-butyl calixarenes themselves complex metals via their aryloxide groups. Since aryloxide complexes are frequently oligomeric, the simple calixarenes do not give monomeric complexes. Aryloxides are hard ligands, therefore they readily form complexes with oxo-philic hard metal ions such as alkali metals, early transition metals, lanthanides, and actinides. Complexation is often inferred because the calixarene acts as a carrier for the metal ion from an aqueous to an organic phase. With the /wa-/-butylcalix[ ]arenes in alkaline solution, a value of n = 6 gives the best carrier for lithium(I), sodium(I), and potassium(I), with a value of n 8 giving the best carrier for rubidium(I) and caesium(I).15,16 Titanium(IV) complexes have been characterized,17-19 as well as those of niobium(V) and tantalum(V).20-22 These complexes are classified as... 

Titanium complexes containing polymerizable vinyl-substituted aryloxide ligands have been employed to prepare polystyrene/divinylbenzene-based polymers that incorporate Ti aryloxide fragment into the matrix 446 Such materials have been used to catalyze Diels-Alder reactions with high diastereoselectivity and at rates only three to five times slower than the corresponding homogeneous reactions. ... 

Titanium-alkoxide/Aryloxide and Related Heterogenised Catalysts... 

Scheme 6.9 ROP of s-CL catalysed by titanium-alkoxide and aryloxide complexes.

Very few heterogeneous alkoxide Ti-based catalysts were reported for the ROP of e-CL. Among the examples, the aforementioned catalysts used for the ROP of LA, i.e. Ti-supported onto (un)modified MCM-41 7-9 and Ti-MOF 10, were also investigated, resulting in a more controlled polymerisation process than the other titanium alkoxide/aryloxide complexes.Only catalyst 7 was tentatively recycled after complete conversion of s-CL (after 15 min) was observed, showing a diminished activity (75% after 2.5 h) due presumably to the catalyst being altered during the recovery procedure. ... 

Vaid PT, Tanski MJ, Pette MJ, Lobkovsky BE, Wolczanski TP. Covalent three-dimensional titanium(lV)—aryloxide networks. Inorg Chem 1999 38(14) 3394-405. 

The preparation of Tbf titanium phenoxides involved the development of a suitable type of chlorotitanium aryloxides as starting material since most complexes of the general formula ClTi(OAr)3Xn (Ar = any phenyl, X = Lewis... 

The efficient syntheses of IVa allows an effective access to the organometallic chemistry of the Tbf moieties. Using the remarkable r -coordinated lithium salts y and VI, monosubstituted titanium(IV) alkoxides and aryloxides become available. The Tbf moiety is coordinated as a sterically demanding Cp derivative in an ii fashion to the titanium centers. The formal benzannula-tion of the fluorenyl system, as present in the Tbf titanium complexes, leads to large mono Cp complexes of high thermal stability compared to ii -fluorenyl titanium derivatives. Due to its heUcal twist, the T -coordinated Tbf ligands show Cl symmetry in the solid state but seem to interconverse in solution. Additionally, the titanium complexes were subjected to polymerization experiments of styrene to some extent. 

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