Nickel 5,14-dimethyl

Nickel Nickel dimethyl glyoxime complex extracted from water AAS 5 (ig/1 [899]... 

The best characterized (35-38) of the oxidized nickel dimethyl-glyoximate species is [Nilv(dmg)3]2-, which can be obtained as the diamagnetic potassium, sodium, or barium salt. Preparation of... 

Nickel-cycloalkynes, synthesis and reactivity, 8, 147 Nickel dimethyl complexes, for Ni(0) complex generation, 8, 83... 

Braun and Metzger [52] showed that trace amounts of nickel obtained from natural environmental samples could be determined voltammetrically as nickel dimethyl glyoximate following adsorptive enrichment onto a rotating glassy carbon electrode, on which a thin mercury film has been deposited electrolytically. See Sect. 7.34.1. 

Dimethylglyoxime reagent (C4Hs02N2) red precipitate of nickel dimethyl-glyoxime from solutions just alkaline with ammonia or acid solutions buffered with sodium acetate ... 

Not all complexes contain complex ions. The well-known nickel dimethyl-glyoxime, bis(dimethylglyoximato)nickel(II), [Ni(C4H702N2)2], (p- 543, Fig. 288 (c)) and bis(acetylacetonato)copper(II) (p. 522) are uncharged molecules,... 

Cherdo S, El Ghachtouli S, Sircoglou M, Brisset F, Orio M, Aukauloo A (2014) A nickel dimethyl glyoxrmato complex to form nickel based nanoparticles for electrocatalytic H2 productiotL Chem Commun 50(88) 13514—13516. doi 10.1039/C4CC05355A... 

Some secondary antioxidants, such as nickel dimethyl dithiophosphate and nickel dimethyldithiocarbamate, can act as photoantioxidants, countering the effect of light-absorbing impurities. 

A variety of electron-deficient olefins were shown to be effective dienophiles, giving the expected cycloaddition products (Table 7.9). Reaction ofthe o-xylylene species 2 with maleic anhydride yielded only the cis product, while cis olefins (e.g., dimethyl or diethyl maleate) yielded a mixture of cis and tram cycloaddition products. Tram esters (diethyl fumarate and methyl crotonate) yielded tram adducts however, fumaronitrile gave a mixture of cis and tram adducts. In a separate experiment, it was discovered that upon exposure to the activated nickel, dimethyl maleate was isomerized to dimethyl fumarate. The exact mechanism of the isomerization is at this point unexplained. Noncyclic cis olefins appear to give mixtures of cis and tram cycloadducts, while tram olefins may yield tram products or mixtures of cis and tram products. In cases where mixtures are produced, the tram isomer is the major adduct isomer with the ratio of cis tram isomers apparently being affected by the nature of the olefin. Thus, although the cycloaddition reaction itself is still not proven to be a concerted rather than a stepwise process, the mixture of cis and tram cycloadducts could arise from isomerization of the olefin prior to the cycloaddition process. 

Accordingly, the addition of an alkali monochromate to the equilibrium reagent solution results in an immediate precipitation of nickel dimethyl-glyoxime. Bichromates, which do not consume hydrogen ions, show no action toward this reagent. As little as 2.5 y K2Cr04 can be detected in one drop, after evaporation of the test solution. 

Nickel dimethyl complexes NiMe2(PRs)2 decompose readily in solution, either thermally or photochemically, providing an efficient method for the generation of Ni(0) complexes. The complex NiMe2(dtbpe) undergoes reductive elimination in benzene at 50-60 °C, giving rise to a binuclear Ni(0) 7r-arene complex. Careful thermolysis in THF-/ 8 over several days at 20 °G affords a 1 2 1 mixture of the ethylene complex 159, the hydride 160, and ethane (Scheme 47). If the reaction is carried out in the presence of ethylene, equimolecular amounts of 159 and ethane are formed. These results can be explained by assuming that the decomposition process involves the formation of a complex. In contrast with this behavior, the bis(carbene) dimethyl complex 45 decomposes... 

The reactions of aqueous solutions of nickel(II) salts with hydroxide ions, with excess ammonia, with sulphide ion and with dimethyl-glyoxime (see above) all provide useful tests for nickel(II) ions. 

The reaction mechanism and rates of methyl acetate carbonylation are not fully understood. In the nickel-cataly2ed reaction, rate constants for formation of methyl acetate from methanol, formation of dimethyl ether, and carbonylation of dimethyl ether have been reported, as well as their sensitivity to partial pressure of the reactants (32). For the rhodium chloride [10049-07-7] cataly2ed reaction, methyl acetate carbonylation is considered to go through formation of ethyUdene diacetate (33) ... 

Reduction. Hydrogenation of dimethyl adipate over Raney-promoted copper chromite at 200°C and 10 MPa produces 1,6-hexanediol [629-11-8], an important chemical intermediate (32). Promoted cobalt catalysts (33) and nickel catalysts (34) are examples of other patented processes for this reaction. An eadier process, which is no longer in use, for the manufacture of the 1,6-hexanediamine from adipic acid involved hydrogenation of the acid (as its ester) to the diol, followed by ammonolysis to the diamine (35). 

Alkyl dimethyl and dialkylmethyl tertiary amines are commercially available. These amines are prepared by reductive methylation of primary and secondary amines using formaldehyde and nickel catalysts (1,3,47,48). The asymmetrical tertiary amines are used as reactive intermediates for preparing many commercial products. 

Solvent for Electrolytic Reactions. Dimethyl sulfoxide has been widely used as a solvent for polarographic studies and a more negative cathode potential can be used in it than in water. In DMSO, cations can be successfully reduced to metals that react with water. Thus, the following metals have been electrodeposited from their salts in DMSO cerium, actinides, iron, nickel, cobalt, and manganese as amorphous deposits zinc, cadmium, tin, and bismuth as crystalline deposits and chromium, silver, lead, copper, and titanium (96—103). Generally, no metal less noble than zinc can be deposited from DMSO. 

Uses ndReactions. Nerol (47) and geraniol (48) can be converted to citroneUol (27) by hydrogenation over a copper chromite catalyst (121). In the absence of hydrogen and under reduced pressure, citroneUal is produced (122). If a nickel catalyst is used, a mixture of nerol, geraniol, and citroneUol is obtained and such a mixture is also useful in perfumery. Hydrogenation of both double bonds gives dimethyl octanol, another useful product. 

Eig. 7. CycHc voltammograms for the reduction of 1.0 mAf [2,2 -ethylene-bis(nitrilomethyHdyne)diphenolato]nickel(II) in dimethyl formamide at a glassy carbon electrode, in A, the absence, and B and C the presence of 2.0 and 5.0 mAf 6-iodo-l-phenyl-l-hexyne, respectively (14). 

The direct combination of selenium and acetylene provides the most convenient source of selenophene (76JHC1319). Lesser amounts of many other compounds are formed concurrently and include 2- and 3-alkylselenophenes, benzo[6]selenophene and isomeric selenoloselenophenes (76CS(10)159). The commercial availability of thiophene makes comparable reactions of little interest for the obtention of the parent heterocycle in the laboratory. However, the reaction of substituted acetylenes with morpholinyl disulfide is of some synthetic value. The process, which appears to entail the initial formation of thionitroxyl radicals, converts phenylacetylene into a 3 1 mixture of 2,4- and 2,5-diphenylthiophene, methyl propiolate into dimethyl thiophene-2,5-dicarboxylate, and ethyl phenylpropiolate into diethyl 3,4-diphenylthiophene-2,5-dicarboxylate (Scheme 83a) (77TL3413). Dimethyl thiophene-2,4-dicarboxylate is obtained from methyl propiolate by treatment with dimethyl sulfoxide and thionyl chloride (Scheme 83b) (66CB1558). The rhodium carbonyl catalyzed carbonylation of alkynes in alcohols provides 5-alkoxy-2(5//)-furanones (Scheme 83c) (81CL993). The inclusion of ethylene provides 5-ethyl-2(5//)-furanones instead (82NKK242). The nickel acetate catalyzed addition of r-butyl isocyanide to alkynes provides access to 2-aminopyrroles (Scheme 83d) (70S593). 

Isothiazolidinones have been desulfurized by Raney nickel (74JOC1210). The 2,1-benzisothiazoline 2,2-dioxide (158) undergoes photocycloaddition with dimethyl acetyl-enedicarboxylate and loss of sulfur dioxide to give a compound of probable structure (168) (80CC471). 

This procedure is based on the method of Lindsay and Hauser as modified slightly by Osgerby and Pauson. N,N-dimethyl-aminomethylferrocene methiodide has also been prepared by heating formylferrocene with dimethylamine and hydrogen in the presence of Raney nickel catalyst to give dimethylamino-methylferrocene, which was quaternized with methyl iodide. ... 

Dimethyl ketals and enol ethers are stable to the conditions of oxime formation (hydroxylamine acetate or hydroxylamine hydrochloride-pyridine). Thioketals and hemithioketals are cleaved to the parent ketones by cadmium carbonate and mercuric chloride. Desulfurization of thioketals with Raney nickel leads to the corresponding methylene compounds, while thioenol ethers give the corresponding olefin. In contrast, desulfurization of hemithioketals regenerates the parent ketone. ... 

This ester is converted in high yield to the y -ketosulfoxide by means of the dimethyl sulfoxide anion. Heating in acetic acid then produces a hemi-mercaptal acetate, which on treatment with Raney nickel gives the desired 21-acetoxy-20-ketone in a 50-70% overall yield from the -ketosulfoxide. A 17a-hydroxyl may also be present during the sequence. 

Hydrogenation of the acridone over Raney nickel gave acridone itself and dimethyl fumarate. 

Dimethyl-1,2,4-triazolium iodide with nickel(II) acetate gives the carbene complex l2Ni( 1,4-dimethyl-l,2,4-triazol-5-ylidene)2 (97OM2209). 

Dimethyl-l,2,2,3-tetramethyl-A -1,2,5-azasilaboroline with [Fe2(CO)9] gives sandwich 62 and sandwich 63 (82AGE207, 82CB738) with Cp)Co(C2H4)2]. With [Ni(CDT)] or in a vapor phase with metallic nickel, sandwich 64 (M =Ni) is formed. The vapor-phase synthesis with iron gives 64 (M = Fe). In all these sandwiches, 62-64, the j " -coordination of the heterocyclic ligand is realized. 

Reaction of -picoline with a nickel-alumina catalyst has been reported to give a mixture of four isomeric dimethylbipyridines, one of which has been identified at 6,6 -dimethyl-2,2 -bipyridine. With palladium-on-carbon, 2,4-lutidine was found to be more reactive than pyridine,and the isolated biaryl has been assigned the structure (2). However, some confusion arises from the statement that this... 

Reaction of -picoline over degassed Raney nickel was found to give 5,5 -dimethyl-2,2 -bipyridine (5), the structure of which was established by its synthesis from 2-bromo-5-methylpyridine. Oxidation of this dimethyl-2,2 -bipyridine, and similar oxidation of the diethyl-2,2 -bipyridine derived from 3-ethylpyridinc, gave the corresponding dicarboxylic acid and the same acid was produced by the action of degassed Raney nickel on sodium nicotinate (in water) or on ethyl nicotinate. These transformations established the 5,5 -substitution pattern for three 2,2 -bipyridines derived from 3-substituted pyridines but such evidence is not available for the biaryls... 

---