Nickel complexes nitroso

The organisms Pyricularia oryzae, which causes rice blast, and Helminthosporium oryzae, which causes brown leaf spot, can be controlled with complexes of the ligands 1-phenyl-3-methyl-4-nitroso-2-pyrazolin-5-one (36) and 3-methyl-4-nitroso-2-pyrazolin-5-one (37). The complexes were of the type ML Xj (L = 36, 37 X = C1-, Br, N03 ) or [ML2]Y2 (Y = C104 ). The former were assigned an octahedral or distorted octahedral structure and the latter are tetrahedral. The most active nickel complex was (38).92... 

The dyes Rhodamine 6G [55] and Crystal Violet [56] form extractable ion-associates with the anionic complexes of nickel with chloro-oxine [551 and 4-chloro-2-nitroso-l-naphthol [56], (e = 7.7-10 - 8.2-10 ). The ion associate of Rose Bengal with the cationic nickel complex with 1,10-phenanthroline, extractable into nitrobenzene, is also the basis of a sensitive method (e > 1-10 ) [57]. Hydroxynaphthol Blue has been applied for determination of Ni in the presence of Cu by the derivative spectrophotometry method [58]. 

Transmetallation of 1-6 or treatment of 1-6 with Lewis acid further broadens the scope of its reaction chemistry. In the presence of CuCl, the reaction of 1-6 with diazo dicarboxylate affords pyridazine derivatives [27]. In the presence of CuCl or nickel complexes, the reaction of 1-6 with alkynes leads to benzene derivatives [28, 29]. Transmetallation of 1-6 with Bids allows further reaction with 2-oxo malonate to give 2/7-pyran derivatives [27]. Transmetallation of 1-6 with CrCls followed by reaction with isocyanates affords pyridine derivatives [30]. Transmetallation of 1-6 with AICI3 followed by reaction with aldehydes affords pentasubstimted cyclo-pentadiene derivatives [31]. Under the similar condition, 1-6 reacts with nitroso compounds to form pyrrole derivatives [32]. Addition of n-butyl lithium activates 1-6 and allows further reaction with carbon monoxide, which leads to carbonylation and affords 2-cyclopentenone upon hydrolysis [33]. 

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 another procedure [522] the sample of seawater (0.5-3 litres) is filtered through a membrane-filter (pore size 0.7 xm) which is then wet-ashed. The nickel is separated from the resulting solution by extraction as the dimethylglyoxime complex and is then determined by its catalysis of the reaction of Tiron and diphenylcarbazone with hydrogen peroxide, with spectrophotometric measurement at 413 nm. Cobalt is first separated as the 2-nitroso-1-naphthol complex, and is determined by its catalysis of the oxidation of alizarin by hydrogen peroxide at pH 12.4. Sensitivities are 0.8 xg/l (nickel) and 0.04 xg/l (cobalt). 

Samples of metal complexes isolated from the final solutions were subjected to microanalysis (for carbon, hydrogen, oxygen, and sulfur). Metals were determined colorimetrically by the following methods— copper as the complex formed with sodium diethyl dithiocarbamate (6) cobalt as the nitroso-R salt complex (7) nickel as the dimethylglyoxime complex (4). 

Tetrakis phosphino complexes of nickel(O) readily react with aliphatic and aromatic nitro compounds RN02 to afford the corresponding nitroso complexes of nickel(0) [Ni(PR3)2(RNO)] and the phosphine oxide. Kinetic studies have been carried out to elucidate the mechanism of this oxygen transfer reaction. The reaction mechanism shown in equations (30)-(32) has been postulated.193... 

Copper salt-amine complexes can also be used for the reduction of aromatic compounds to the corresponding amine.A more general and convenient method for reducing nitroso compounds to amines involves the use of a nickel/aluminum alloy. The low cost and ready commercial availability of nickel/aluminum alloy are important features of this reduction procedure which may find wide acceptance as a preparative method. 

Several other nitroso compounds have been investigated by PES. The nitrosyl halides, Hal-NO, are basic inorganic compounds. Of particular inteest for organic chemists are nitrosamines, R2N—NO, and nitrites, RO—NO. The NO group occurs as a ligand in transition metal complexes and PE spectra of complexes of chromium, manganese, iron, cobalt and nickel have been measured. ... 

Metal complexes. In this range the metal is chelated rather than being used to form a salt. The two best known examples are ferro-nitroso-beta-naphthol green and nickel azo yellow. Both pigments are dull and sensitive to acids. The nickel azo pigment has excellent light stability. 

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