Acylcobalt Carbonyls Research Articles

The tale of alkyl- and acylcobalt carbonyls

The almost centennary history of alkyl- and acylcobalt carbonyls started with preparative and structural interest in these particular compounds, but the attention also soon included important industrial problems. These two driving forces induced intense research toward this compound class, which produced useful experimental details for the petrochemical industry and led to unexpected new application possibilities at the dawn of the 3rd millennium. In this review, an attempt is made to deduce the most characteristic features of the history of these compounds, to collect interesting, unexpected discoveries from related research and to list the newest possible discoveries offered by the most recent results. This paper does not intend to provide a complete literature list; only those reports will be mentioned, which are regarded as important steps forward, with special attention given to the results obtained by the László Markó (Veszprém, H) team, who was one of the leading personalities of petrochemical and organometallic chemistry research in the 2nd half of the 20th century. This paper is dedicated to his memory.

Intermediates of cobalt-catalysed PTC carbonylation of benzyl halides

AbstractIntermediates of the cobalt carbonyl-catalysed carbonylation ofortho-substituted benzyl halides were identified by IR, 1 H- and 13 C-NMR spectra. The molecular structures of the acyl-type derivatives 2-MeC 6 H 4 CH 2 C(O)Co(CO) 3 PPh 3 and2-PhC 6 H 4 CH 2 C(O)Co(CO) 3 PPh 3 were determined by X-ray crystallography. Structural features of these complexes arediscussed.© 2003 Elsevier Science B.V. All rights reserved. Keywords: Phase transfer catalysis; Hydroxycarbonylation; Carbonylation; Acylcobalt carbonyls; Alkylcobalt carbonyls; 3 -benzylcobaltcarbonyls 1. IntroductionPhase transfer catalysis (PTC) became a well-estab-lished, environmentally friendly (green) method inpreparative organic chemistry [1]. The combinationof PTC with transition metal molecular catalysts(TM) is one of the most promising potentialities oftransition metal chemistry. TM–PTC is characterisedby dramatic increase in reaction rates, consequentlyenables mild conditions, favourable operational costsand high selectivities [2–8].

Reaction of cobalt tetracarbonyl hydride with phenylacetylene

Abstract In C6H6 or hexane at room temperature, under an atmosphere of CO, excess HCo(CO)4 reacts with phenylacetylene to give ethylbenzene and 2-phenylpropanal, the same products that result from the similar reaction of styrene. This and other evidence show that styrene is an intermediate. However, when phenylacetylene is in large excess, neither ethylbenzene, 2-phenylpropanal, nor styrene is formed in more than trace quantity. Instead, a compound is formed whose spectral properties suggest that it is an alkyl- or acylcobalt carbonyl containing a 1-phenylethenyl group. This compound reacts with HCo(CO)4 to give styrene. CIDNP suggests that the reaction of phenylacetylene with HCo(CO)4 proceeds through radical pairs [1-phenylethenyl··Co(CO)4].

ChemInform Abstract: Synthesis, Characterization and Reactions of Acylcobalt Carbonyl Complexes, RC(O)Co(CO)4‐nLn (n = 0, 1, 2, 3)

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis, characterization and reactions of acylcobalt carbonyl complexes, RC(O)Co(CO)4−nLn (n = 0, 1, 2, 3)

Synthesis, characterization and reactions of acylcobalt carbonyl complexes, RC(O)Co(CO)4−nLn (n = 0, 1, 2, 3)

Carbonylation-decarbonylation reactions of the carbomethoxymethylcobalt complexes CH 3O 2CCHRCo(CO) 3L (R [sbnd] H, CH 2CO 2CH 3; L [sbnd] CO, PPh 3) and their acyl derivatives

The primary and secondary alkyl- and acylcobalt carbonyl complexes CH 3O 2CCHRCo(CO) 3L and CH 3O 2CCHRC(O)Co(CO) 3L (R H or CH 2CO 2CH 3; L CO, PPh 3) ( 1–8) have been prepared and studied by a variety of IR and 1H, 13C 1H, 31P 1H and 17O 1H NMR spectroscopic methods. Unlike their primary analogues, all the secondary complexes readily undergo a reversible carbonylation-decarbonylation reaction. The new alkyl complex trans-CH 3O 2CCH 2Co(CO) 3PPh 3 ( 3) was characterized in solution, and exhibited remarkably different properties from the well-known homologue trans-CH 3CH 2O 2CCH 2Co(CO) 3PPh 3, i.e. it readily decomposes to [Co(CO) 3PPh 3] 2, suggesting homolytic dissociation of the carbon-cobalt bond, and its IR spectrum exhibits an organic ν(CO) absorbance at an unusually low frequency, pointing to an oxygen-cobalt interaction. The corresponding acyl complex trans-CH 3O 2CCH 2C(O)Co(CO) 3PPh 3 ( 4) was isolated as a stable solid, but smoothly decarbonylated in solution to 3. Multinuclear NMR spectroscopic monitoring of this reaction suggested the intermediate formation of cis-CH 3O 2CCH 2Co(CO) 3PPh 3, providing the first direct evidence for alkyl migration in cobalt carbonyl complexes.

Activation of molecular hydrogen in cobalt-catalyzed hydroformylation

The mechanism of the activation of molecular hydrogen in cobalt-catalyzed hydroformylation of olefins has been studied by high pressure IR spectroscopy using HCo(CO) 4 ( 1) under 100 bar H 2 (or D 2) in the absence or presence of CO at room temperature. The treatment of 1 with 100 bar H 2 resulted in the formation of CO 2(CO) 8 ( 2) and a small amount of Co 4(CO) 12 ( 3), and the transient formation of HCo 3(CO) 9 ( 4). In the reaction of 1 with one equivalent of 3,3-dimethyl-butene-1 under 100 bar H 2 both hydrogenation and hydroformylation occur, but the former is much faster. In the presence of large amounts of 1 the predominant path for the hydrogenation of the olefin involves the reaction of two equivalents of 1 with the olefin even under 100 bar of H 2. Under a very low partial pressure of CO the stability of 1 is increased and the hydrogenation significantly slowed down. The preferred path of the hydroformylation of the olefin involves the addition of H 2 and CO from gas phase even in the presence of large amount of HCo(CO) 4 ( 1) under 100 bar H 2 and 2.3 bar COat room temperature. The studies reveal that the mechanism of H 2 activation in the presence of HCo(CO) 4 ( 1) is highly dependent on the reaction conditions. Under 100 bar H 2 and at room temperature the activation of molecular hydrogen starts at a coordinatively unsaturated acyl cobalt carbonyl, yielding an aldehyde and an unknown cobalt species. It is believed that this species is a coordinatively unsaturated hydrido cobalt carbonyl like {HCo(Co) 3}, and can activate and catalytically hydroformylate the olefin.

Synthesis of Substituted Butadienolides via Cobalt Carbonyls

Acyl cobalt carbonyl compounds, which are substituted in the α-position with a leaving group, react with internal alkynes to give rise to substituted butadienolides (5-methylene-2(5H)-furanones) in good yield.

Reductive carbonylation of cobalt(II) in the presence of diphenylphosphine: synthesis and structure of (PPN)[Co(CO) 3(PPh 2OMe)] and MeCOCo(CO) 2(PPh 2H)(PPh 2OMe)

Cobalt(II) is reduced to Co(−I) by PPh 2H in the presence of CO in MeOH solution containing NaOMe; the complex (PPN)[Co(CO) 3(PPh 2OMe)] ( 1) was isolated from the reaction product in 12% yield. Alkylation of the cobaltate anion with MeI gave after addition of PPh 2H the disubstituted acylcobalt carbonyl complex MeCOCo(CO) 2(PPh 2H)(PPh 2OMe) ( 2). The crystal structures of both complexes were determined: 1 monoclinic, P3 1/ n, a 10.748(3), b 13.255(2), c 32.123(8) Å, β 93.15(2)°, V 4569(2) Å 3, Z = 4, R(F) 0.048. 2 monoclinic, P2 1/ n, a 14.440(5), b 16.768(6), c 11.526(3) Å, β 102.27(3)°, V 2727(2) Å 3, Z = 4, R(F) 0.068. The anion of 1 contains a tetrahedral Co coordination geometry and 2 a trigonal bipyramidal geometry with the PPh 2OMe and MeCO groups occupying axial positions.

Cleavage of acylcobalt carbonyl with hydridocobalt tetracarbonyl

La reaction CH 3 (CH 2 ) 4 CO Co(CO) 4 +HCo(CO) 4 a lieu avec une cinetique du 2eme ordre. La vitesse est independante de la pression partielle de CO. Il y aurait homolyse reversible rapide du complexe acyl suivie d'un arrachement d'hydrogene de HCo(CO) 4

Synthesis of acylcobalt carbonyl complexes by phase transfer and three phase catalysis

Some acylcobalt carbonyl compounds were prepared by reaction of RCH 2X (X = Cl, Br, I) with the cobalt carbonyl anion by phase transfer and three phase catalysis. A comparison between these two methods shows that the three phase system is twenty times less efficient than the two phase system.

Behaviour of acylcobalt carbonyls under “oxo” conditions

Behaviour of acylcobalt carbonyls under “oxo” conditions

Isomerization of disproportionation of acylcobalt carbonyls

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIsomerization of disproportionation of acylcobalt carbonylsWolfgang Rupilius and Milton OrchinCite this: J. Org. Chem. 1972, 37, 7, 936–939Publication Date (Print):April 1, 1972Publication History Published online1 May 2002Published inissue 1 April 1972https://doi.org/10.1021/jo00972a003RIGHTS & PERMISSIONSArticle Views66Altmetric-Citations18LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (508 KB) Get e-Alerts Get e-Alerts

Reactions of Potassium Iron Carbonylate with Olefins and Alkyl Halides

Abstract Potassium iron carbonylate, KHFe(CO)4, reacted with ethyl acrylate, crotonate, 3-butenoate, styrene, and α-olefins at 40–70°C under an atmosphere of carbon monoxide. Methylmalonate was selectively obtained from the acrylate by treatment of the reaction mixture with an alcoholic iodine and hydrogen chloride solutions. Dipotassium iron carbonylate, K2Fe(CO)4, reacted with β-bromopropionate to give mainly methylmalonate. Isomerization of β-ethoxycarbonylpropionyliron carbonylate to the α-isomer occurred readily in contrast to isomerization of acylcobalt carbonyl. Both crotonate and 3-butenoate gave ethylmalonate as a major product and methylsuccinate and glutarate as minor ones. The results suggest that α-ethoxycarbonylbutyliron carbonylate is more predominant than the corresponding β- and γ-isomers in equilibrium state. This is in striking contrast to the case of acylcobalt carbonyl. Styrene yielded two isomeric aldehydes, α- and β-phenylpropionaldehydes. Ethyl caproate and enanthate were obtained from 1-pentene and 1-hexene, respectively in poor yield.

The Reaction of Cobalt Hydrocarbonyl with Vinylacetate, Crotonate, Styrene, and Acrylates

Abstract Ethyl vinylacetate and ethyl crotonate reacted with cobalt hydrocarbonyl at 25°C to give three isomeric acylcobalt carbonyls, α- and γ-carbethoxy-butyrylcobalt carbonyls and β-carbethoxy-iso-butyrylcobalt carbonyl. The distribution of these complexes depends greatly on the reaction time (0.5–20 hr). In both cases the β-isomer predominates at shorter reaction times (0.5–1.5 hr), while the γ-isomer predominates at longer reaction times. This shows that isomerization occurs among the complexes and that the equilibrium is very favorable to the γ-isomer. Acrylates and styrene react with cobalt hydrocarbonyl to give two isomeric acylcobalt carbonyls. The isomerization of the acylcobalt complex with a branched structure to that with a straight-chain structure is much promoted by the phenyl and ester groups. The promoting effect of the ester groups is the highest in benzyl, followed by allyl, and ethyl, isopropyl, butyl, and cyclohexyl. Such a promoting effect can reasonably be attributed to the −I effect of these groups.

Studies of the Organic Reaction of Metal Carbonyl. VIII. The Isomerization of Aliphatic C5- and C6-Acylcobalt Carbonyls

Abstract The isomerization of C5-acyl(n-valeryl- and α-methylbutyryl-) and C6-acyl(n-caproyl-, α-methylvaleryl- and α-ethylbutyryl-) cobalt carbonyls has been studied and compared with that of C4- acyl(n- and isobutyryl-) cobalt carbonyls previously reported. It has been observed that solvents have great effects on the isomerization (the rate and equilibrium) of the C5-acylcobalt carbonyls. The equilibrium proportion of the isomers (iso/normal) is almost 1 in diethyl ether and tetrahydrofuran. In solvents such as dioxane, ethyl acetate and benzene it seems difficult for this isomerization to occur. α-Ethylbutyrylcobalt carbonyl appears to isomerize directly to n-caproylcobalt carbonyl. However, n-caproylcobalt carbonyl isomerizes only to α-methylvaleryl-cobalt carbonyl; the reverse isomerization also occurs, but it seems very difficult for any other isomerization between the two of them to occur.

The Addition of Acylcobalt Carbonyls to α,β-Unsaturated Carbonyl Compounds. 1-Acyloxy-π-allylcobalt Tricarbonyl Derivatives

The Addition of Acylcobalt Carbonyls to α,β-Unsaturated Carbonyl Compounds. 1-Acyloxy-π-allylcobalt Tricarbonyl Derivatives

Studies of the Organic Reactions of Metal Carbonyls. VI. The Isomerization of Acylcobalt Carbonyls—The Effects of Solvents and of the Structure of the Acyl Group

Abstract The reactions of n-butyryl chloride, isobutyryl bromide, α-ethylbutyryl chloride and n-caproyl chloride with potassium cobalt carbonylate have been studied. The results of this investigation are as follows. (1) It has been observed that solvents have great effects on the isomerization of butyrylcobalt carbonyls, as do the reaction temperature and the atmosphere. The rate and the equilibrium of this isomerization are remarkably affected by the solvents; in polar solvents, the equilibrium proportion of products (iso/normal) is almost zero in dioxane, 1/3 in ethyl acetate, and 1 in diethyl ether. This isomerization proceeds more rapidly under nitrogen atmosphere than under carbon monoxide. On the other hand, in nonpolar solvents such as benzene this isomerization apparently does not occur. (2) α-Ethylbutyrylcobalt carbonyl relatively readily isomerizes to n-caproylcobalt carbonyl. This isomerization is also accelerated under nitrogen atmosphere.

Studies of the Organic Reaction of Metal Carbonyl. V. The Reaction of Cobalt Hydrocarbonyl with Olefin—The Effects of the Reaction Conditions and of the Structure of Olefin

Abstract It has been observed that the reaction of 1-olefin with cobalt hydrocarbonyl is remarkably affected by the reaction conditions and by the structure of olefln. Some functional groups, such as the ester, n-butoxy and phenyl groups, adjacent to a C= C bond increase the reactivity of the C=C bond; the order of the reactivity is n-butyl vinyl ether, 103>styrene, 20>ethyl acrylate, 5>pentene-1. (The numbers indicate the relative reactivities, which have been roughly calculated from the gas absorption curve.) At a relatively low temperature (below 0°C), the α-carbon atom of the C=C bond of all these olefins except pentene-1 is selectively carbonylated; the reaction scheme may be considered to be as follows; suggesting that cobalt hydrocarbonyl is acting as an acid: (Remark: Graphics omitted.) However, these acylcobalt carbonyls with the branched structure isomerize to those with the straight one: (Remark: Graphics omitted.) A relatively high temperature (25°C) and a nitrogen atmosphere promote this isomerization considerably. The reverse isomerization seems to occur only with difficulty. On the other hand, these olefins mainly give the β-carbon carbonylated product at 25 °C, the formation of which seems to result from the two successive reactions, the carbonylation of the α-carbon atom and the isomerization of the corresponding acylcobalt carbonyl. However, the distribution of the products from pentene-1 is not affected by the reaction temperature. A relatively high pressure of carbon monoxide is advantageous for this reaction. Under a nitrogen atmosphere, some reaction other than the carbonylation seems to occur very rapidly, consuming a large part of the cobalt hydrocarbonyl used; a nitrogen atmosphere has an inhibitory effect on the carbonylation.

The Addition of Acylcobalt Carbonyls to Acetylenes. π-(2,4)-(Alkeno-4-lactonyl)cobalt Tricarbonyl Derivatives and Their Conversion to 2,4-Pentadieno-4-lactones

The Addition of Acylcobalt Carbonyls to Acetylenes. π-(2,4)-(Alkeno-4-lactonyl)cobalt Tricarbonyl Derivatives and Their Conversion to 2,4-Pentadieno-4-lactones