Vanadium chelated

Not all vanadium chelates have antidiabetic properties in animals. For instance, four mixed 0,S binding bidentate ligand precursors were derived from maltol to yield four new complexes, two pyranthiones and two pyridinethiones. These complexes are hydrolytically stable and had no observable insulin-enhancing properties [147], The ultimate effectiveness of a vanadium-complex as an antidiabetic drug... 

Investigation of non-ferrous metal chelates that can efficiently absorb NO and provide stability toward oxidation. Many cobalt, copper, manganese, molybdenum, nickel, osmium, rhenium, rhodium, ruthenium and vanadium chelates have been demonstrated to be able to coordinate NO. Their application to flue gas scrubbing systems should be explored. 

The following review presents the selective, but rather insensitive methods based on the use of BPHA and 8-hydroxyquinoline, a moderately sensitive method involving 4-(2-pyridylazo)resorcinol (PAR), and a very sensitive method based on the ion-associate of a vanadium chelate complex with Brilliant Green... 

All known X-ray diffraction data indicate that in penta-coordinated pyramidal vanadium chelates the vanadium atom lies out of the basal plane of the ligand macrocycle, i,e.j the plane of the four pyrrole nitrogen atoms. The distance from vanadium... 

Urine samples can be determined directly or after preconcentration by mineralization and vanadium chelation followed by solvent extraction. 

Savitskii and co-workers found that aldehydes or ketones could be prepared by liquid phase oxidation of alcohols in the presence of vanadium chelates [310]. CIDNP was used to study the oxidation of 2-propanol using titanous ion with hydrogen peroxide [311 ]. A variety of radical species were identified in this reaction [311]. 

By using rare earth metals or radicals it is possible to copolymerize 1,3-butadiene and other dienes with cis-, A linkage [3,498]. Polymers of 1,3-butadiene and isoprene at any ratio can be obtained. Copolymes of 1,3-butadiene and 1,3-pentadiene can be produced with catalysts on the basis of vanadium chelates. 1,3-Butadiene is almost completely converted to trans-, A units, whereas 1,3-pentadiene yields 50 to 60% 1,4-addition and 40 to 50% 1,2-addition products. At a 1,3-pentadiene content of 26 to 45wt%, the copolymers are amorphous, featuring high rigidity [499-501]. Diethylaluminum chloride, nickel naphthenate, and water catalyze the copolymerization of 1,3-butadiene and acetylene. The low-molecular-weight copolymers contain mostly cis-Q-Q double bonds [502]. 

General Purpose Computer Program for Exact EPR Spectrum Calculations with Application to Vanadium Chelates... 

The Lo-Cat process, Hcensed by US Filter Company, and Dow/Shell s SulFerox process are additional Hquid redox processes. These processes have replaced the vanadium oxidizing agents used in the Stretford process with iron. Organic chelating compounds are used to provide water-soluble organometaHic complexes in the solution. As in the case of Stretford units, the solution is regenerated by contact with air. 

Citric acid is used to chelate vanadium catalyst in a process for removing hydrogen sulfide from natural and refinery gas and forming elemental sulfur, a valuable product (133). 

Aliwi and coworkers have investigated many vanadium (V) chelate complexes as photoinitiators for vinyl polymerization [36-43]. The mixed ligand complex of chloro-oxo-bis(2,4-pentanedione) vanadium (V). VO(a-cac)2 Cl is used as the photoinitiator of polymerization... 

The polymerization of MMA photoinitiated by al-koxo-oxo-bis(8-quinolyloxo) vanadium (V) complex [VOQ2 OR] has also been studied [38,39]. The alkyloxo radical ( OR) formed from the photodecomposition of the chelate (A = 365) nm at 25°C) was found to be the initiating species ... 

In another type of mixed ligand oxo-vanadium Schiff base complexes chloro-oxo-bis[N(4-bromophe-nyl) salicylideneiminato] vanadium (V) chelate, VOL2CI, and methoxo-oxobis[N(4-bromophenyl)sali-cylideneimine vanadium (V) chelate, VOL2OCH3 Aiiwi and Salih [43] show that these complexes are active pho-... 

A novel type of grafting process was developed using a new photosensitive polymer containing vanadium (V) chelates. These polymers were generally synthesized by the condensation of a VOQ2OH complex and a hydroxy-containing polymer to produce photoactive polymer (red in color) with pendant vanadium (V) chelate. 

The cobalt complex is usually formed in a hot acetate-acetic acid medium. After the formation of the cobalt colour, hydrochloric acid or nitric acid is added to decompose the complexes of most of the other heavy metals present. Iron, copper, cerium(IV), chromium(III and VI), nickel, vanadyl vanadium, and copper interfere when present in appreciable quantities. Excess of the reagent minimises the interference of iron(II) iron(III) can be removed by diethyl ether extraction from a hydrochloric acid solution. Most of the interferences can be eliminated by treatment with potassium bromate, followed by the addition of an alkali fluoride. Cobalt may also be isolated by dithizone extraction from a basic medium after copper has been removed (if necessary) from acidic solution. An alumina column may also be used to adsorb the cobalt nitroso-R-chelate anion in the presence of perchloric acid, the other elements are eluted with warm 1M nitric acid, and finally the cobalt complex with 1M sulphuric acid, and the absorbance measured at 500 nm. 

Another reagent that has found use in pinacolic coupling is prepared from VC13 and zinc dust.264 This reagent is selective for aldehydes that can form chelated intermediates, such as (3-formylamides, a-amidoaldehydes, a-phosphinoylaldehydes,265 and 8-ketoaldehydes.266 The vanadium reagent can be used for both homodimerization and heterodimerization. In the latter case, the reactive aldehyde is added to an excess of the second aldehyde. Under these conditions, the ketyl intermediate formed from the chelated aldehyde reacts with the second aldehyde. 

Monien and Stangel [598] studied the performance of a number of alternative chelating agents for vanadium, and their effect on vanadium analysis, by atomic absorption spectrometry with volatilisation in a graphite furnace. Two promising compounds were evaluated in detail, namely 4-(2-pyridylazo) resorcinol in conjunction with tetraphenylarsonium chloride and tetramethylenedithiocar-bamate. These substances, dissolved in chloroform, were used for extraction... 

Morris [814] separated microgram amounts of vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc from 800 ml of seawater by precipitation with ammonium tetramethylenedithiocarbamate, and extraction of the chelates at pH 2.5 with methylisobutyl ketone. Solvent was removed from the extract, the residue was dissolved in 25% nitric acid, and the inorganic residue was dispersed in powdered cellulose. The mixture was pressed into a pellet for X-ray fluorescence measurements. The detection limit was 0.14 pig or better when a 10 min counting period was used. 

Ion exchanger colorimetry has been used as a sensitive and rapid method for vanadium analysis by immobilization of 2[2-(3-5-dibromopyri-dyl)azo]-5-dimethylaminobenzoic acid onto an ion exchanger resin AG 1X2 [75]. Solid phase fluorimetry can be useful for the analysis of very dilute solutions in water analysis or trace metal determination thus a chelating 8-(benzene-sulfonamido)quinoline, immobilized on Amberlite XAD2 support, has been used for the spectrofluorimetric determination of Zn(II) and Cd(II) [76]. 

The Grinization complexes include all vitally needed macro-, micro-and ultra-microelements that are compulsory components of the animal and vegetable matter being their source used in Grinization complexes production. With the scope of the Grinization complexes, functional activity increase, and some essential macro- and microelements are added, such as calcium, magnesium, zinc, manganese, silicium, vanadium these are included into the complexes in the most solvable and acceptable form of chelates. 

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