Cobalt cyanates

Properties Colorless to It. yel. oily liq. ammonialike odor sol. in alcohol, ether, oxygenated soivs. insol. in water m.w. 197.28 dens. 1.017 m.p. -26 C b.p. 300 C ref. index 1.5740 Toxicology Irritant TSCA listed Uses Rubber activator vulcanization accelerator corrosion inhibitor bacteriostat intermediate amination reagent reagent for metals detection of cobalt, cyanate, and iron Manuf./Distrib. ABCR http //www.abcr.de, Acros Org. http //www.acros.be, Aldrich http //www.sigma-aldrich.com, Alfa Aesar http //www.aifa.com, Bayer http //WWW. bayerus. com Cambrex http //www.cambrex.com, Fluka http //www.sigma-aidrich.com, ICN Biomed. Research Prods, http //www.icnbiomed.com, Interchem http //www.interchem.com, Koei Chem. http //www.koeichem.com Lancaster Synthesis Noveon Kalama Pfaltz Bauer http //www.pfaitzandbauer.com, Robinson Bros. Ltd http //www.robac.co.uk, Sithean... 

For colorimetric or gravimetric determination l-nitroso-2-naphthol can be used. For chromatographic ion exchange (qv), cobalt is isolated as the nitroso-(R)-salt complex. The cyanate complex is used for photometric determination and the thiocyanate for colorimetry. A rapid chemical analysis of... 

Determination of cobalt as cobalt tetrathiocyanatomercurate(II) (mercurithio-cyanate) Discussion. This method is based upon the fact that cobalt (II) in almost neutral solution forms a blue complex salt Co [ Hg( SCN )4] with a reagent... 

The scope of this chapter is based on the analogous one by Naso and Marchese published in 19831. Since the time of their review, the focus of work in this area has shifted somewhat, and sections have been added or omitted to reflect that focus. New sections covering chromium(II)-mediated reactions of halides and covering cobalt-mediated radical reactions of halides have been added. In view of the relatively mature nature of the areas, sections dealing with 7c-allylnickel complexes, iron oxyallyl cations and cyanation reactions have been omitted. 

Table 19 Cyanate, Thiocyanato and Selenocyanato Complexes of Cobalt(IIl)...

Cobalt acetate solution When the reagent is added to a concentrated solution of potassium cyanate, a blue colouration, due to tetracyanatocobaltate(II) ions, [Co(OCN)4]2- is produced. The colour is stabilized and intensified somewhat by the addition of ethanol. 

Cyanate. (i) Dilute H2S04 test (IV.9, 1). (ii) Cobalt acetate solution test (IV.9, 5). (iii) Copper sulphate-pyridine test (IV.9, 6). 

The first mechanism is. in fact, reminiscent of the well-known copper-catalyzed dimerization of acetylene viny(acetylene being the main by-product of this process. This side reaction can, however, be inhibited to some extent by the use of cobalt salts as additives [IS]. The cyanation of acetylene and of alkenyl halides is also promoted by Co and Ni cyanides and Pd catalysis. A reducing reagent, such as Zn or NaBll4, has been used in conjunction with cobalt cyanide complexes, and the formation of. succinonitrile has been reported to result from the basebase-catalyzed hydrocyanation of acrylonitrile. 

A number of mixed-hgand cyanates of cobalt(III) and (II) are given in Table XXVII, which lists only a representative sample of the large number of such complexes available. In many cases the results were discussed in terms of variations in u or tt bonding or of steric effects. These discussions will not be rehearsed in this section but, where relevant to this review, will be referred to later. With the exception of... 

SAFETY PROFILE A poison. An irritant. Mutation data reported. Flammable liquid when exposed to heat or flame can react vigorously with oxidizing materials. Has exploded when stirred with (cobalt pentammine triazoperchlorate + nitrosyl perchlorate). When heated to decomposition it emits toxic fumes of CN and NOx. See also CYANATES. 

To facilitate the program it was decided to study the cobalt(II)-thio-cyanate complex system which was as accessible to direct assay in the exchanger phase as it was in the solution phase by absorption spectrophotometry in the visible region. Both Co(II) and Co(SCN) exhibit sizably different spectral absorption properties in the visible region. Assuming that the presence of higher complexes than one to one in the cation... 

Cobaltaie(l -), dodecacarbonylirontri-, tetraethylammonium, 27 188 Cobaltate(l -), dodecacarbonylirontri-, (triphenylphosphine)gold(l -(-), 27 188 -------, dodecacarbonylrutheniumtri-, tetraethylammonium, 26 358 Copper, (acetonitrile)dodecacarbonyltrico-balt ruthenium-, 26 359 Crystal growth, 26 377 Cyanate, tungsten complex, 26 42 Cycloheptatriene, molybdenum complex, 27 4... 

Meprobamate is hydrolyzed in an alkaline alcoholic medium to yield a cyanate which forms a blue colored complex with cobalt ions. For analyses >37,38,39 the intensity of the color has been determined at 603 mu. 

These results coupled with the greater success of nickel and palladium catalysts may explain the long interval preceding the next report on cobalt catalysts . Cobalt(I) complexes (see Table 1) are, however, effective hydrocyanation catalysts, not only in hydro-cyanating olefins such as 4-pentenenitrile, but also are effective for isomerizing 2-methyl-... 

An x-ray study of the cyanate and cyanide derivatives of the native enzyme has shown that the anions sit in the cavity without binding to the metal ion (M. Lindahl, L.A. Svensson, and A. Liljas, Proteins 15 (1993), 177). Since NCO has been shown to interact with the paramagnetic cobalt(II) center, and C-enriched cyanide has been shown to interact with Zn-substituted CA (see Reference 67), it appears that the structures in the solid state and solution are strikingly different. 

Cobalt complexes, 635-882 ADP, 760 amides, 682 arsenates, 774 arsenic ligands, 767-775 ATP, 760 bipyridyl, 691 bis(dithiolates), 876 carboxylates, 790 cyanates, 679 cyanides reduction, 646 disulfides, 829... 

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