Vanadium ethoxide

VO(OR)3 — the alkoxides of vanadyl (V) or otherwise the esters of vanad-ic acid — belong to the most easily available derivatives and can be easily purified by distillation under low vacuum. The synthesis of these derivatives — from ethoxide to t-amyloxide—via alcoholysis of V2Os was first described at the beginning ofthe twentieth century by Prandtl and Hess [1313,743], The same work contained the first description ofthe hydrolysis of VO(OR)3, which laid basis for the numerous studies of the processes of formation of sols and gels of vanadic acid. The studies of the low-valent derivatives of vanadium that are very sensitive to oxidation were started in the 1960s by the works of Bradley on V(OR)4 and V(OR)3 [226]. The preparation, structure, and magnetic properties of vanadium(II) alkoxides were investigated only quite recently. 

Dissolution of (HPS)VO(OEt)(EtOH) in DMF, as mentioned previously, gives rise to four resonances, which are assigned to five species (Scheme 3). Addition of 0.5 M ethanol converts all the vanadium in solution to a single species with a resonance at —530 ppm. This species is assigned as (HPS)VO(OEt) (35). (Evidence that ethanol binds as ethoxide will be presented.) If methanol is added instead of ethanol, the sole resulting resonance is at —524 ppm, assigned as (HPS)VO(OMe). Addition of ethanol and methanol results in resonances at both —524 and —530 ppm (37). This complex may coordinate a solvent molecule in the axial position trans to the oxo group. Either formulation (five- or... 

The eight vanadium centers within the wheel are alternately bridged by two carboxylates and a hydroxide, or by one carboxylate and two ethoxides. Both these bridging motifs are found in rings of other metals. No further studies have been reported on this cage, which is surprising. 

Aerogels of titania, titania-silica, and titania-vanadia were prepared with titanium butoxide, silicon ethoxide, and vanadium triisopropoxide as precursors. The titania and titania-silica aerogels were then used as supports for vanadia, introduced by the incipient wetness impregnation of vanadium triisopropoxide and the subsequent calcination at 773 K. 

Mosset A., Galy J. Synthesis and structural study of the entity titanium oxide ethoxide (Tii60i6-(0C2H5)32) An example of intramolecular twinning. Comp. Rend., Ser. 2. 1988 307 1747 Nabavi M., Sanchez C., Livage J. Sol-gel synthesis of vanadium oxide from alkoxides. Eur. J. Solid State Inorg. Chem. 1991 28 1173... 

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