Vanadyl complexes

R spectra, 2, 511 Vanadium tetramethoxide spectroscopy, 2, 347 Vanadyl acetylacetonate, 2, 388 hydrolysis, 2, 379 Vanadyl complexes cupferron... 

The first xanthates of V(IV), [Cp2V(Rxanth)] (R = Me, Et, Pr , or Bu), isolated as purple solids were prepared by the same method (71). Kwoka et al. (70) were able to obtain an alkylenebis(dithiocarbamate) vanadyl complex, VO[SjjCNH(CH2) NHCS2] for n — 2, but not for... 

Finally, the vanadyl complex was tested in the trimethylsilylcyanation of aldehydes (Scheme 5) [17] and a significant effect of the anion in the solvent... 

The same group showed (Baumeister et al., 1997) that addition of vanadyl compounds as cocatalysts solved a recurring problem in hydrogenations the build-up of arylhydroxylamine intermediates, which can lead to runaway reaction conditions. Vanadyl complexes catalyse the disproportionation of aiylhydroxylamines and, hence, prevent their build-up during... 

Interesting results have been presented by Baleizao et al. for chiral vanadyl Schiff base complex [50].120 The 29Si MAS NMR spectra have confirmed covalent grafting of the vanadyl complex into the silicate skeleton. 

Quinoxaline bis-A-oxides have been investigated as potential anti-cancer agents 93 <06BMC6917> and anti-trypanosomal agents 94 <06BMC5503>. In the latter case, a vanadyl complex was prepared in order to increase bioavailability. 

Sakurai et al. have observed that vanadyl complexes with coordination modes such as VO(S4) (103) can normalize blood glucose levels (515) and are effective for normalizing both serum glucose and free fatty acid levels in streptozotocin rats and are orally active (516). Bis(picolinato)oxovanadium(IV) is also orally active against the diabe-... 

In octahedral vanadyl complexes, the weakest Kgand is usually found trans- to the 0X0 group. The v(V=0) stretching frequency is indicative of the Kgand trans- to the V=0 bond. As u-donor ability increases, v(V=0) decreases [80]. This trend was examined in a series of compounds [VO(DCP)L2] (DCP = 2,6-dicarboxylatopyridine, L2 = (H20)2, o-phenanthroline, bipyridine) which displayed reversible reduction chemistry... 

Figure 6. Probable structures of vanadyl complexes of salicyl phosphate...

Many vanadyl complexes are not air stable and generally they can be easily hydrolyzed and/or oxidized to the +5 oxidation state. 

Table 27 Forward Rate Constants for Vanadyl Complexation (/ = 0.5 M KN03 and T = 25 °C)...

Table 38 Spin-Hamiltonian Parameters for Vanadyl Complexes...

Many investigations have involved vanadyl complexes of type (66),599a,723 726 particularly with 1,2-diamines. In the solid state /4 a values are normally near the spin-only value.725,727... 

The second transition (16,000 cm.-1) appears as a weak shoulder and is assigned to it is allowed vibronically and should appear in all polarizations. The B2 -> 2Ax transition apparently is hidden under the first charge transfer band of VOSO HsO it is observed, however, at approximately 30,000 cm.-1 in a few vanadyl complexes. 

Several room temperature magnetic susceptibility measurements have been made for both powdered samples and aqueous solutions of vanadyl complexes.34 38 The effective magnetic moments arrived at are listed in Table VI. The... 

Berger, S.L., and C.S. Birkenmeier. 1979. Inhibition of intractable nucleases with ribonucleoside-vanadyl complexes Isolation of messenger ribonucleic acid from resting lymphocytes. Biochemistry 18 5143. 

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