Vanadyl fluoride

Phenanthrenequinones. Subsi tion on treatment with vanadyl fluoride ai the phenanthrenequinones range from 82 ... 

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. 

In Table 5 the values for the free standard enthalpies for the reactions of neutral donors and anion donors with vanadyl acetylacetonate are listed. It can be seen that towards the reference molecule iodide ion is a somewhat weaker ligand than propanediol carbonate, whereas the bromide ion is between tri-methylphosphate and acetone, and the chloride ion between DMF and DMSO 22>. The fluoride ion and the NCS -ion are stronger donors than all neutral donors but are somewhat weaker than the azide and the cyanide ion. 

The use of a special microtechnique has permitted the precipitation, weighing, and determination of about 2 /xg of technetium with a standard deviation of 0.08 /xg . The precipitate is filtered, washed with ice-cold water, dried at 110 °C and weighed as (CgH5) AsTcO. Permanganate, perchlorate, periodate, iodide, fluoride, bromide, thiocyanate anions and mercury, bismuth, lead, silver, tin and vanadyl cations as well as nitrate concentrations above 0.5 M interfere with the determination. 

Vanadyl Difluoride, VOF2, is prepared by the action of anhydrous hydrogen fluoride on vanadyl dibromide, VOBr2. It is a yellow substance. Density at 19° C., 3-3956.s A hydrated vanadyl difluoride, V0F2.a, H20, is obtained as microscopic blue crystals when hypovanadic oxide, V02, is dissolved in excess of hydrofluoric acid and the solution concentrated slowly over sulphuric acid.1 The following double salts have been prepared, all of which are crystalline and fairly stable —5... 

Bis(acctonitro)chloronitropalladium(II). /-Butyl hydroperoxide-Dialkyl taitratesr-Vanadium(IV) isoproxide. t-Butylhydroperoxide-Molybdenum carbonyl. t-Butylhydroperoxide-Vanadyl acetylacetonate. [(— )-Camphor-10-ylsulfonyl]-3-aryloxaziridines. m-Chloroperbenzoic acid-Potassium fluoride. Dimethylsulfonium methylidc. 3,5-Dinitroperbenzoic acid. Hydrogen peroxide-Vilsmeier reagent. p3-Oxohexakis(p-... 

Vanadium (V, at. mass 50.94) occurs in the V, IV, III, and II oxidation states, vanadium(V) compounds being the most stable. In alkaline medium, the colourless vanadate VOs ions exist, whereas in strongly aeidic media, the yellow V02 cations are present. Within the intermediate pH range polymerized orange-yellow anionic forms occur. Vanadium(V) forms heteropoly acids with P(V), Mo(VI), and W(VI), and also peroxide complexes. Vanadium(IV) occurs as the blue vanadyl ion V02", stable in acid solutions and readily oxidized to vanadium(V) in alkaline solution. The VO cation is amphoteric. At pH 4, V0(0H)2 precipitates and at pH 9 it dissolves. Vanadium(IV) forms fluoride-, oxalate-, and... 

Vanadium tetrachloride, 332—333 Vanadyl acetylacetonate, 331 Vilsmeier reaction, 128 Vilsmeier reagents, 16, 321 Vinyl cyanides, 212 4-Vinylcyclohexene, 25, 209 Vinyl fluorides, 146 Vinyl halides, 186, 212-213 Vinylsilanes, 187... 

The IV state. This is the most important oxidation state of Ti where the main chemistry is that of Ti02 and TiCl4 and its derivatives. This is also an important state for vanadium which forms the vanadyl ion V02+ and many derivatives, cationic, anionic, and neutral containing the VO group. For the remaining elements, Cr-Ni, the IV state is found mainly in fluorides, fluoro complex anions, and cation complexes however, an important class of compounds are the salts of the oxo ions and other oxo species. 

The reactivity of fluorine toward synthetic vanadyl porphyrins, Boscan crude, and fractions derived therefrom was surprisingly benign. The halogen was actually less reactive than chlorine toward metallo-porphyrins. Though the crude and its fractions did react with the formation of hydrogen fluoride, the processes did not exhibit explosive violence at ambient and even higher temperatures. 

DMSO)3VOCl2] + DMSO [(DMSO)4VOCl]+ + Gilt is expected that vanadyl bromide will completely ionize in dimethylsulph-oxide or tributylphosphate, but the situation may be different for fluorides because the fluoride ion has stronger donor properties than bromide or chloride ions towards class (a) metals. Ionization of cyanides and thiocyanates of class (a) metals is unlikely in solvents of donor number below 25 iodides and bromides of class (a) metal ions are completely ionized in solvents of high donor numbers, whilst iodides and bromides of class (b) metals are not ionized in the same media. 

Preparation of Aromatic Fluoro Derivatives. Reaction of (1) with Vp2, VF4, Vanadyl Trifluoride, or Xenon(II) Fluoride in HF, CFCI3, or MeCN at —30 to 20 °C yields mixtures of perfluoro-2,5-cyclohexadien-l-one together with its 2- and 4-pentafluorophenoxy derivatives and/or perfluoro-6-phenoxy-2,4-cyclohexadien-l-one, along with traces of perfluoro-2-cyclohexen-l-one or perfluoro-p-benzoquinone. Using Anti-mony(V) Fluoride or NbFa, however, only gives stable complexes or pentafluorophenolates, ... 

---