Reaction with nickel tetracarbonyl

The phase-transfer catalysed reaction of nickel tetracarbonyl with sodium hydroxide under carbon monoxide produces the nickel carbonyl dianions, Ni,(CO) 2- and Ni6(CO)162, which convert allyl chloride into a mixture of but-3-enoic and but-2-enoic acids [18]. However, in view of the high toxicity of the volatile nickel tetracarbonyl, the use of the nickel cyanide as a precursor for the carbonyl complexes is preferred. Pretreatment of the cyanide with carbon monoxide under basic conditions is thought to produce the tricarbonylnickel cyanide anion [19], as the active metal catalyst. Reaction with allyl halides, in a manner analogous to that outlined for the preparation of the arylacetic acids, produces the butenoic acids (Table 8.7). 

Isomerism of the but-3-enoic acids into the E-but-2-enoic acids is base-catalysed (Table 8.8), whereas the formation of the other isomers indicates the participation of rt-allylnickel complexes in the reaction. Potassium nickel tetracarbonyl is a considerably poorer catalyst, compared with nickel cyanide, whereas nickel sulphate and nickel iodide are ineffective catalysts. 

Aryltellurium trichlorides and diaryltellurium dichlorides react with nickel tetracarbonyl in DMF, giving benzoic acids. Small amounts of diaryl tellnrides and diaryl ketones are by-products of these reactions. 

The reaction of allylic halides with nickel tetracarbonyl to form coupled products has been known for over two decades (9), but it is only in recent years that an insight into the mechanism has been obtained. Isolation of the intermediate 7r-allylnickel complexes and the discovery that these react with activated olefins and organic halides in general have led to a considerable increase in the scope of the reaction. 

Aromatic halides are reported to give only carbonylated products with nickel tetracarbonyl. In contrast, pentafluorophenyl iodide in DMF gives decafluorobiphenyl in 70% yield (27). From the other products obtained (pentafluorobenzene, decafluorobenzophenone) it has been suggested that a radical mechanism is involved. The reactions of benzyl halides with nickel carbonyl in various solvents have been reported (28). The main reaction involves carbonylation, as discussed in Section III. Using benzene as solvent, a 33% yield of bibenzyl may be obtained. Here again a mechanism involving a 7r-allylnickel derivative should perhaps be considered, particularly since such a system is known to exist in (XVI) (29). 

Reaction of aryllithium with nickel tetracarbonyl at — 70 C gives a black, insoluble, air-sensitive powder which is believed to be lithium aroyltricarbonyl nickelate (62, 63). These lithium salts are highly reactive and on hydrolysis produce a-diketones and acyloins. 

Scheme 1.1 The reaction of nickel tetracarbonyl with l,2-dichloro-l,2,3,4-tetramethylcyclo-butene (1) which gave the tetramethylcyclobutadiene nickel complex 3 instead of tetramethylcyclobutadiene (2)...

G. N. Schrauzer, Bisacrylonitrile Nickel and Related Complexes from the Reaction of Nickel Tetracarbonyl with Compounds Containing Activated Double Bonds, J. Am. Chem. Soc. 81, 5310-5312 (1959). 

The reaction of 75 with nickel tetracarbonyl gives the cyclopentadienone-nickel complex (81), thermal decomposition of which yields the cyclopentadienone 82 . 

Halogen bridged, dimeric 7r-allynickel halides. III, were first described by Fischer and Burger, who prepared them in low yields by the reaction of nickel tetracarbonyl with allylic halides (9, 10),... 

The vapometahurgical refining of nickel is based on the reaction of the metal with carbon monoxide to form gaseous nickel tetracarbonyl... 

It has been pointed out that the types of solvents which are used here, are not generally such as would enter into strong association with the substrate. The molecularity of the substitution reaction may then stand more chance of being an operational concept. Amongst the binary carbonyls, the only systems which have been extensively studied have been nickel tetracarbonyl and the hexacarbonyls of group VI. For the former, the observation of a first-order rate is at least consistent with a rate-determining dissociation of one carbonyl ligand followed by reaction of the intermediate with whichever nucleophile should be available. 

According to the free energy change associated with the pertinent reaction, nickel will form nickel tetracarbonyl at low temperatures, and this carbonyl will become unstable and revert back to nickel and carbon monoxide at moderate temperatures. The Mond process for refining nickel is based on these features. In this process, impure nickel is exposed to carbon monoxide gas at 50 °C, whereby volatile nickel tetracarbonyl (Ni(CO)4) forms. No impurity present in the crude nickel reacts with carbon monoxide. Since formation of the... 

It is supposed that the nickel enolate intermediate 157 reacts with electrophiles rather than with protons. The successful use of trimethylsilyl-sub-stituted amines (Scheme 57) permits a new carbon-carbon bond to be formed between 157 and electrophiles such as benzaldehyde and ethyl acrylate. The adduct 158 is obtained stereoselectively only by mixing nickel tetracarbonyl, the gem-dibromocyclopropane 150, dimethyl (trimethylsilyl) amine, and an electrophile [82]. gem-Functionalization on a cyclopropane ring carbon atom is attained in this four-component coupling reaction. Phenyl trimethyl silylsulfide serves as an excellent nucleophile to yield the thiol ester, which is in sharp contrast to the formation of a complicated product mixture starting from thiols instead of the silylsulfide [81]. (Scheme 58)... 

There have been some reports of the use of N-sulfinyl compounds to transfer both a nitrogen and a sulfur atom. An example is the reaction of N-sulfinylcyclohexylamine (59 R = cyclohexyl) with diphenylcyclopropenone in the presence of nickel tetracarbonyl. An isothiazolinone S-oxide (62) was the product.80 Similarly, A-sulfinyl-/>-toluenesulfonamide (59 R = tosyl) and the Wittig reagent triphenylphosphonium phenylbenzoylmethylide give 1,2,3-thiadiazoline (63).8 ... 

In particular, chemists observed that nickel could bond with carbon monoxide. The resulting compound, nickel tetracarbonyl, Ni(C0)4, is a gas. At the time, the nature of the bonding in this compound was unexplainable. Even so, chemists could easily produce and decompose Ni(C0)4. The chemical reactions involved were used to purify nickel, and led to the establishment of a company that later became International Nickel Company, INCO. 

Finely divided nickel combines with carbon monoxide to form zero valent nickel tetracarbonyl, Ni(CO)4. The reaction occurs at 50°C and one atmosphere, although it is usually carried out at 200°C under high CO pressure between 100 to 400 atm for high yield of carbonyl, and to prevent product decomposition. Carbon monoxide at ordinary pressure may be passed over freshly reduced metal to form the tetracarbonyl. 

Nickel tetracarbonyl may be prepared in the laboratory by the Hieber process, a disproportion reaction of several nickel compounds of organic thio acids, such as nickel(II) phenyldithiocarbamate, (CeHs— NH—C(=S)—S)2Ni, with carbon monoxide under controlled conditions. In such disproportionation reactions, the divalent nickel ion converts to a tetravalent nickel complex (Hieber. H. 1952. Z.anorg.Chem., 269, pp. 28). The overall reaction is ... 

The ring may be cleaved hydrogenolytically. Halo acids afford 4-halobutanols or 1,4-dihalobutanes, depending on the reaction conditions. Acid chlorides in the presence of zinc chloride afford esters of 4-chlorobutanol, and LAH and aluminum chloride give butanol. Reaction with carbon monoxide and nickel tetracarbonyl affords adipic acid. 

Nickel tetracarbonyl is known to dissociate into the more reactive tricarbonyl readily [step (1)] and this species is known to react readily with a variety of halides by oxidative addition presumably as shown in steps (2) and (3). Subsequent loss of CO would give an equilibrium mixture of the four complexes shown in (3). Step (4) is the well-known carbon monoxide insertion reaction. The acylnickel complex formed in this step then may re-ductively eliminate acid halide [step (5)], which then alcoholizes [step (6)] or it may react directly with alcohol to form ester and a hydridonickel complex (7), which then reacts with CO and decomposes to nickel tricarbonyl and HC1 (8) ... 

The Mond process for purifying nickel involves the reaction of impure nickel with carbon monoxide at about 150°C to give nickel tetracarbonyl. The nickel tetracar-bonyl then decomposes to pure nickel at about 230°C ... 

Finally, NiCl(NO)(PPh3)2 also was obtained by Addison and Johnson ) by adding triphenylphosphine to the reaction product of tetracarbonyl-nickel with nitrosylchloride. 

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