Cobalt Tetracarbonyl Anion Research Articles

Calculation of the possibility of formation of a cyclic metallolactone anionic complex in the methyloxirane-potassium tetracarbonylcobaltate system

The reaction of the tetracarbonylcobaltate anion with methyloxirane was studied by quantumchemical methods to show that a metallocyclic complex is energetically preferred over an alkylcobaltcarbonyl one.

Chromium(III) Octaethylporphyrinato Tetracarbonylcobaltate: A Highly Active, Selective, and Versatile Catalyst for Epoxide Carbonylation.

The development of a highly active and selective porphyrin-based epoxide carbonylation catalyst, [(OEP)Cr(THF)2][Co(CO)4] (1; OEP = octaethylporphyrinato; THF = tetrahydrofuran), is detailed. Complex 1 is a separated ion pair composed of a tetracarbonylcobaltate anion and an octahedral chromium porphyrin complex axially ligated by two THF ligands. Regarding the carbonylation of epoxides to β-lactones, catalyst 1 exhibits excellent turnover numbers (up to 10 000) and turnover frequencies (up to 1670 h-1), with regioselective carbonyl insertion occurring between the oxygen and the sterically less hindered carbon of the epoxide substrate. Complex 1 is highly tolerant of nonprotic functional groups, carbonylating an array of aliphatic and cycloaliphatic epoxides, as well as epoxides with pendant ethers, esters, and amides. With careful control of reaction conditions in the carbonylation of glycidyl esters, the exclusive production of either the β- or γ-lactone isomer was achieved. Through analysis of reaction...

Chromium(III) Octaethylporphyrinato Tetracarbonylcobaltate: A Highly Active, Selective, and Versatile Catalyst for Epoxide Carbonylation

The development of a highly active and selective porphyrin-based epoxide carbonylation catalyst, [(OEP)Cr(THF)2][Co(CO)4] (1; OEP = octaethylporphyrinato; THF = tetrahydrofuran), is detailed. Complex 1 is a separated ion pair composed of a tetracarbonylcobaltate anion and an octahedral chromium porphyrin complex axially ligated by two THF ligands. Regarding the carbonylation of epoxides to beta-lactones, catalyst 1 exhibits excellent turnover numbers (up to 10,000) and turnover frequencies (up to 1670 h(-1)), with regioselective carbonyl insertion occurring between the oxygen and the sterically less hindered carbon of the epoxide substrate. Complex 1 is highly tolerant of nonprotic functional groups, carbonylating an array of aliphatic and cycloaliphatic epoxides, as well as epoxides with pendant ethers, esters, and amides. With careful control of reaction conditions in the carbonylation of glycidyl esters, the exclusive production of either the beta- or gamma-lactone isomer was achieved. Through analysis of reaction stereochemistry, a mechanism for the formation of gamma-lactone products was proposed. Overall, a broad array of synthetically useful lactones has been synthesized in a rapid and selective fashion by catalytic carbonylation using [(OEP)Cr(THF)2][Co(CO)4].

A readily synthesized and highly active epoxide carbonylation catalyst based on a chromium porphyrin framework: expanding the range of available beta-lactones.

[reaction: see text] Catalytic carbonylation of epoxides to beta-lactones was effected by a highly active and selective bimetallic catalyst comprised of a chromium(III) porphyrin cation and a cobalt tetracarbonyl anion. The complex is readily synthesized from commercially available compounds in high yield. Carbonylation of numerous linear epoxides, as well as bicyclic epoxides derived from 8- and 12-membered hydrocarbons, proceeded with high activity, selectivity, and yield.

Lanthanide-transition-metal carbonyl complexes. 1. Syntheses and structures of ytterbium(II) solvent-separated ion pairs and isocarbonyl polymeric arrays of tetracarbonylcobaltate.

Transmetalation reactions of metallic ytterbium with Hg[Co(CO)(4)](2) in the coordinating solvents pyridine and THF yield the solvent-separated ion pairs [Yb(L)(6)] [Co(CO)(4)](2) (1a, L = Pyr; 2a, L = THF). The IR spectrum of 1a in pyridine indicates that the tetracarbonylcobaltate anion is not directly bonded to the divalent Yb cation owing to the strong coordinating ability of pyridine. On the other hand, IR spectra of 2a in THF are concentration dependent. In dilute solutions there is an equilibrium between the solvent-separated ion pair and a weak contact ion pair. Higher concentrations of 2a facilitate the formation of a tight ion pair that has a low-frequency isocarbonyl absorption. Remarkably, complexes 1a and 2a are easily transformed in toluene into the two-dimensional sheetlike arrays [(Pyr)(4)Yb[(mu-CO)(2)Co(CO)(2)](2)](infinity) (1b) and [(THF)(2)Yb[(mu-CO)(3)Co(CO)](2).Tol](infinity) (2b). The two-dimensional frameworks are supported by isocarbonyl linkages. Infrared spectra of toluene solutions substantiate the existence of the isocarbonyl bridges with low-frequency absorptions at 1780 cm(-1). Compounds 1b and 2b belong to a rare class of lanthanide-transition-metal carbonyl extended arrays, only three others of which have been structurally established. Dissolving 1b in pyridine regenerates 1a, but the complete conversion of 2b into 2a cannot be achieved. Crystal data: 1a.Pyr is monoclinic, P2(1)/c, a = 11.171(1) A, b = 11.925(1) A, c = 33.978(1) A, beta = 95.10(1) degrees, Z = 4; 2a is monoclinic, C2/c, a = 17.724(1) A, b = 12.468(1) A, c = 18.413(1) A, beta = 100.34(1) degrees, Z = 4; 1b is monoclinic, C2/c, a = 11.047(1) A, b = 13.423(1) A, c = 21.933(1) A, beta = 103.49(1) degrees, Z = 4; 2b is monoclinic, C2/c, a = 28.589(1) A, b = 7.223(1) A, c = 14.983(1) A, beta = 118.90(1) degrees, Z = 4.

Inversion of Stereochemistry in the Co2(CO)8-Catalyzed Carbonylation of Aziridines to β-Lactams. The First Synthesis of Highly Strained trans-Bicyclic β-Lactams

β-Lactams were synthesized by the carbonylative ring expansion of aziridines catalyzed by dicobalt octacarbonyl under CO pressure. The active catalyst, cobalt tetracarbonyl anion, induces nucleophilic ring opening of the heterocycle, resulting in inversion of configuration. The regio- and stereospecificity of this reaction resulted in the synthesis of the first highly strained trans-7-azabicyclo[4-2-0]octan-8-one derivatives.

Cobalt catalysed carbonylation of reactive chlorides into esters by methyl formate without carbon monoxide and methanol added

Reactive chlorides ZCH 2Cl (Z = C 6H 5, CH 3OC(O), CN) are readily carbonylated into esters with methyl formate as the sole source of carbon monoxide and methanol, the tetracarbonyl cobaltate anion as the catalyst and sodium carbonate as the base. The reaction occurs after in situ prior mild decomposition of methyl formate with a catalytic amount of sodium methoxide.

Palladium-catalysed formation of aroylcobalt complexes from iodoarene and tetracarbonylcobaltate anion. Syntheses, characterization and reactivities of model intermediate complexes

The complex [Pd(PPh3)4] showed good catalytic activity for the formation of aroylcobalt complexes [Co(OCR)(CO)3(PPh3)] from RI (R = aryl), K[Co(CO)4] and PPh3. Attempts to isolate an intermediate Pd–Co complex in this catalytic reaction were unsuccessful, however a series of heterodinuclear complexes [(Ph3P)(OC)RPtCo(CO)3(PPh3)](R = Ph 1a, C6H4Me-4 1b or Me 1c), [(Me3P)2(PhCO)PdCo(CO)4]2 and [(Me3P)2PhPtCo(CO)4]3 have been prepared from reactions of [MR(O3SCF3)(PR′3)2](M = Pt or Pd, R′= Me or Ph) with K[Co(CO)4] as model intermediate complexes. Prior to the formation of complex 1, transient formation of [(Ph3P)2RPtCo(CO)4] was confirmed by 31P NMR spectroscopy of the reaction solution. The reaction of [PtPh(O3SCF3)(PMe3)2] with K[Co(CO)4] led to the isolation of the corresponding Pt–Co complex 3, while the palladium analogue resulted in the formation of the CO insertion product 2. Crystal structures of compounds 1a, 1c, 2 and 3 were determined by X-ray diffraction analyses. Addition of ligands L such as CO, ButNC and PMe3 to 3 in tetrahydrofuran induced heterolytic cleavage of the Pt–Co bond to form [PtPh(PMe3)2L][Co(CO)4]. Thermolysis of complexes 1b and 1c under CO at 50 °C resulted in reductive elimination of Co(OCC6H4Me-4)(CO)3(PPh3) and Co(OCMe)(CO)3(PPh3), respectively, from the platinum centre. This strongly suggests the involvement of this type of heterodinuclear Pd–Co complex in the catalytic formation of aroylcobalt complexes.

Ion-pair charge transfer (IPCT) between bipyridinium cations and the tetracarbonylcobaltate anion. Spectroscopy and thermal and photochemical reactions

Ion-pair charge transfer (IPCT) between bipyridinium cations and the tetracarbonylcobaltate anion. Spectroscopy and thermal and photochemical reactions

ChemInform Abstract: Synthesis of Aryl Methyl Ketones Mediated by Cobalt Tetracarbonyl Anion.

AbstractDurch Umsetzung der Arylbromide (I) mit Methyliodid (II) und Kohlenmonoxid (III) erhält man unter Co‐Katalyse die Acetophenone (IV) und die Benzoesäuren (V).

Synthesis of aryl methyl ketones mediated by cobalt tetracarbonyl anion

The reaction of aryl halides with excess of methyl iodide in the presence of cobalt tetracarbonyl anion (generated under phase-transfer conditions), gave aryl methyl ketones along with aromatic carboxylic acids.

Carbonylation of chloromethylated polystyrene resins with NaCo(CO)4 in phase-transfer catalysis

The carbonylation of Chloromethylated and partial quaternizated Chloromethylated polystyrene resins with cobalt tetracarbonyl anion in phase-transfer conditions is described.

Kinetics and mechanism of the phase-transfer-catalyzed carbonylation of benzyl bromide by cobalt tetracarbonyl anion

La reaction est etudiee dans des systemes a 2 phases H 2 O/CH 2 Cl 2 , H 2 O/(i-propyl) 2 O, H 2 O/C 6 H 6

Tetracarbonyl cobaltate ion supported on anion exchangers as a new heterogenized homogeneous catalyst: synthesis of acids and esters from organic halides

Catalysts consisting of tetracarbonyl cobaltate anion supported on commercially available anion exchange resins are readily prepared. Carbonylation of organic halides using this heterogenized catalyst leads either to acids or esters depending on the conditions. Some features of this catalytic system and the possible reaction mechanism are discussed.

Synthetic Approaches to η 1-iminoacylcobalt carbonyl complexes

Reaction of imidoyl chlorides with triphenylphosphinecobalt tricarbonyl anion or with cobalt tetracarbonyl anion in the presence of triphenylphosphine affords η 1=iminoacylcobalt carbonyl complexes in 19–85% yields.

New effective desulfurization reagents

Hydrocarbons and amines are formed in good yields by treatment of thioketones and thioamides, respectively, with iron pentacarbonyl and potassium hydroxide (i.e., HFe(CO)/sub 4//sup -/). A different, and useful, desulfurization reaction occurred by the use of dicobalt octacarbonyl, the cobalt tetracarbonyl anion, or cyclopentadienyliron dicarbonyl dimer as reagents. Mechanisms are proposed for several of these reactions.

Syntheses of organometallic compounds containing iminoacyl ligands. Reactions of metal carbonyl anions with imidoyl halides

Reactions of metal carbonyl anions with imidoyl halides provide a convenient route for the preparation of organometallic complexes containing both η 1- and η 2-iminoacyl ligands. With poorer nucleophiles such as tetracarbonyl cobaltate anion, coupling of imidoyl groupings becomes important. This is illustrated by the molecules Co 2(CO) 5(P(CH 3) 2C 6H 5){(C 6H 5)CN(C 6H 5)} 2 which has been crystallographically analyzed.

Generation of the cobalt tetracarbonyl anion by phase transfer catalysis, applications to the synthesis of π-allyl and cluster complexes

Phase transfer catalysis provides a simple, convenient, and rapid means for preparing π-allylcobalt carbonyl and alkylidynetricobalt nonacarbonyl complexes.

Indium(III) and thallium(III) complexes of the tetracarbonylcobaltate anion

Indium(III) and thallium(III) complexes of the tetracarbonylcobaltate anion

The anion of mercury cobalt carbonyl

Mercury cobalt carbonyl is reduced in tetrahydrofuran by 1 equivalent of sodium amalgam to the anion {[Co(CO) 4] 2Hg} − which can be precipitated by [Fe(C 12H 8N 2) 3] 2+. Reduction by excess sodium amalgam leads to the tetracarbonyl cobaltate anion.