Vanadium cyanides

From the viewpoint of chemical and physical requirements the permissible indicators involve a number of criteria mercury, selenium, cadmium, vanadium, chromium, arsenic, silver, lead, barium, cyanides, hydrogen sulphide, fluorides, phenols, oil and oil substances, COD(Mn), colour, odour, taste and turbidity. The most stringent criterion concerns the content of mercury, followed by selenium, cadmium, vanadium, cyanides, oil and oil substances. Another important indicator is the content of organic matters characterized by COD(Mn). 

An old compound, K2V(CN)6,389 was reformulated as K3[VO(CN)5],390 based on a band at 935 cm-1 assigned to v(V=0). Mabbs and co-workers assigned v(V=0) at 930 cm-1, which probably reflects high electron density in the vanadium from the CN- 369 ESR studies of [VO(CN)3-] anion indicate significant covalency.356 UV-visible spectra of solutions containing V02+ and cyanide do not support the existence of V(CN)1-.391... 

Double cyanides of trivalent vanadium have been prepared which show the properties of co-ordinated compounds, e.g. Ks[V(CN)g] compare with K3[Cr(CN)6] and K3[Fe(CN)6]. 

Salts, sawdust, scrap metals, shales, silicates, soda ash, sodium chloride, sodium compounds, sodium cyanide, sponge iron, steel turnings, stone wool, sugar, sulfur Teas, tin, titanium sponge, turnings Urea, urea formaldehyde Vanadium, vermiculite, vitamins Waxes, welding powder, wood dust, wood shavings Yeast (dry)... 

Vanadium(II) reacted with SCN- and diphenylguanidine (L) to form a ternary complex with a V SCN L ratio of 1 2 2.176 Other ternary complexes like phenylguanidine iron(II) cyanide are being exploited in titrimetric determination of cyanide ions, for example. 

Vanadium(m) forms more stable complexes with NCSe- ion in acetone and methyl cyanide than in DMF.383 Spectroscopic detection of the 1 3 and 1 2 complexes in acetone, the 1 2 complex in methyl cyanide, and the 1 1 complex in all three solvents has been achieved. Stepwise stability constants of the complexes are reported as are their electronic spectral parameters. V(antipyrene)3(NCSe)3 and V(diantipyrrylmethane)(NCSe)3 have been isolated from ethanol solutions. 

A full account of the crystal structure determination of potassium heptacyano-vanadate(m) dihydrate has appeared.387 Apart from clearing up the uncertainty surrounding the nature of the vanadium(m) cyanide complex, this study has established the V(CN)7- ion as one of the very few examples of a seven-co-ordinate complex containing only simple unidentate ligands. The choice of this co-ordination number has been rationalized on the basis of the nine-orbital rule. The two electrons of the paramagnetic V(CN)4 ion (pef = 2.8 BM) occupy two separate orbitals,... 

Cyanopyrazine is obtained in 90% yield by the reaction of phos-phoryl chloride and carboxamidopyrazine. The reactants are first kept at room temperature for 5 hours and then heated under reflux for 40 minutes.228 Commercially, cyanopyrazine is prepared by reaction of methylpyrazine with a mixture of ammonia and air in the presence of a catalyst. The catalysts used are Co, Fe, Sn, and Ag vanadates and vanadium phosphotungstate.229 Bromopyrazines are readily converted into cyanopyrazines by treatment with cuprous cyanide in boiling y-picoline.230... 

Since the vanadium center of vanadocenes is electron-deficient, various vanadium derivatives are formed by the attack with PR3, CO, or unsaturated tt-donating hgands/ This reaction provides a useful synthetic method for the synthesis of jj -alkene complexes as described later. Thus formed Cp 2V(CO) (22) is converted to the cyano derivative (23, see Cyanide Complexes of the Transition Metals) on treatment with the isocyanide (Scheme 12). ( -C5Me5)2V is incubated with O2 at -78 °C to yield [(/u.-)] -C5Me503)V(0)]2 via oxygen insertion into the carbon-vanadium bond." ... 

---