Vanadium complex preparations

Bis(guanidinato)bis(benzyl) complexes, with Zr(IV), 4, 776 Bis(heteroarene) vanadium complexes, preparation, 5, 48 Bis(heteroatom) polysilanes, synthesis, 3, 584 Bis(iV-heterocyclic carbene) ligands, in silver(I) complexes,... 

Shaver, A., J.B. Ng, D.A. Hall, B. Soo Lum, and B.I. Posner. 1993. Insulin-mimetic peroxo vanadium complexes Preparation and structure of potassium oxodiper-oxo(pyridine-2-carboxylato)vanadate(V), K2[V0(02)2(C5H4NC00)]-2H20, and potassium oxodiperoxo(3-hydroxypyridine-2-carboxylato)vanadate(V), K2[V0(02)2 (0HC4H3NC00)]3H20, and their reactions with cysteine. Inorg. Chem. 32 3109-3113. 

In 1995, Bolm and Bienewald introduced a new, very practical method for the asymmetric catalytic oxidation of sulfides [44]. In the presence of aqueous hydrogen peroxide afforded the corresponding sulfoxides with enantiomeric excesses of up to 85% (Eq. 2). Only traces of the corresponding sulfones were observed. The transformation can easily be carried out in open vessels at room temperature using inexpensive H2O2 as oxidant. 

Prepare KBr discs of the four vanadium complexes prepared. Run their infrared spectra in the range 400-4000 cm . Compare the complexes of V(III) and V(IV) and comment on your results. 

The chromium, tungsten, and vanadium complexes can be prepared by an entirely analogous procedure. 

Heteroalkenes, with iron, 6, 132 Heteroannulation, allylic benzylamines, 10, 156 Heteroarene chromium carbonyls, preparation and characteristics, 5, 260 Heteroarenes borylation, 10, 242 C—H functionalizations, 10, 127 as metal vapor synthesis milestone, 1, 237 with titanium, 4, 246 vanadium complexes, 5, 48 7]6-Heteroarenes, with platinum, 8, 664 Heteroaromatic compounds... 

Schwendt, P., A. Oravcova, J. Tyrselova, and F. Pavelcik. 1996. The first tetranuclear vanadium)V) peroxo complex Preparation, vibrational spectra and x-ray crystal structure of K7[V204(02)8(P04)] 9H20. Polyhedron 15 4507 4511. 

Reaction of (R)-(+)-tert-butyl ferf-butanethiosulfinate (52) with lithiated imine 53 gave 54 as a single isomer in 92% yield.39 The thiosulfinate 52 was prepared by asymmetric oxidation of rerf-butyldisulfide with H202 in the presence of a chiral vanadium complex. 

Scheme 43. The Fischer-type see Fischer-type Carbene Complexes) vanadium complexes are prepared by treatment of (butadiene)hafhocene (81) or (butadiene)zirconocene with CpV(CO)4 (Scheme 44). The equilibrium mixture reacts with cyclopentanone to give the adduct complex (82). - ...

C,Hk, 1,3-Cyclopentadiene, 1-methyl-, preparation and purification of, 27 52 titanium complex, 27 52 vanadium complex, 27 54, 55 QH,Oj, Ascorbic acid, platinum complex, 27 283... 

Vanadium. A residual oil was desulphurized (673 K, 115 atm) with a non-stoicheiometric vanadium sulphide (S/V, 0.8-1.8) formed in situ from VS4 Vanadium sulphide catalysts have been prepared by in situ sulphiding of vanadium complexes, e.g., bis(acetylacetonato)oxovanadium(IV), dissolved in crude petroleum.Vanadium compounds occurring in heavy oils have been activated as desulphurization and demetallization catalysts by treatment with triethylaluminium. Catalysts consisting of vanadium promoted by nickel can be prepared in situ by deposition of the metals from heavy crude oils. Ni-V hds and hdm catalysts on silica or carbon have been claimed. 

The complexes derived from simple monodentate carboxylates are not stable, and only one mononuclear complex with a sterically hindered carboxylate has been successfully isolated, [VCKCbC Bujs] (13).103 Attempts to prepare carboxylates in organic solvents often led to the formation of oligomeric cluster compounds with a variety of interesting structural types.103 In aqueous solutions, these vanadium complexes appear to contain six-coordinate vanadium.60,104 Even carbonate has been found to form a weak vanadiumtV) complex in solution.105... 

A cyanohydridoborato vanadium(II) complex, tra s-[V(NCBH3)2(thf)4], has been synthesized and structurally characterized (212).858 Additional oligomeric complexes have been prepared complexes that have been characterized include trinuclear vanadium complexes,859-862 dinuclear V-Fe complexes,863 and the first tetranuclear V11 species [V4(/x3-Cl)2(M-Cl)2(M-CF3C02)2(thf)6].864 The addition of tris(pyrazolyl)borate ligand to the tetranuclear species results in the dissociation of the complex to form a neutral dimeric species [V(tpb)-(/x-Cl)(/x-CF3CO2)2V(th03] (213) in which one of the vanadium centers is facially coordinated by tpb.864... 

Lapina et al. [58] observed by H MAS NMR that V2O5 on Si02/Ti02 interacts both with Si02 and Ti02. From data obtained from NMR it was found that the structure of vanadium complexes at the surface depends on the sequence of V and Ti deposition. However, the effect of the preparation technique on the SCR reaction... 

Vx-MFI and Vx-p Differently from the above catalysts, in V-MFI (ZSM-5 structure) and V-P (Beta structure) the zeolite was prepared first and then the vanadium component was added by incipient wet impregnation at r.t. using a peroxide complex of vanadium obtained by reaction at r.t. of V2O5 with H2O2. The use of the V-peroxide complex increases the solubility of the vanadium complex, avoiding the possible precipitation at contact with the zeolite crystals and thus avoiding deposition on the outer surface. 

Quite a different chemical environment is found in the vanadium-containing material isolated from the mushroom Amanita muscaria. Bayer and Kneifel, who named and first described amavadine, " also suggested the structure shown in Figure. l Recently the preparation, proof of ligand structure, and (by implication) proof of the complex structure shown in Figure 1.7 have been established. Although the exact role of the vanadium complex in the mushroom... 

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