12119-11-8

Upstream product

• 12078-25-0 dicarbonylcyclopentadienylcobalt 
• 124-38-9 carbon dioxide 
• 501-65-5 diphenyl acetylene 
• 1277-43-6 cobaltocene 
• 479-33-4 2,3,4,5-tetraphenylcyclopenta-2,4-dienone 
• 201230-82-2 carbon monoxide 
• 15321-51-4 diiron nonacarbonyl 
• 91946-70-2 {K-18-crown-6-ether}{(η5-cyclopentadienyl)cobalt(cyanide)(CO)} 

Relevant academic research and scientific papers

CpCo(CO)2-catalysed cyclotrimerisation of alkynes in supercritical carbon dioxide

The reactivity of mono-substituted HCCR (R=Ph, a; CH2OH, b; CH2CH2CH2CH3, c) and di-substituted RCCR (R=CH2CH3, d; CO2CH3, e; Ph, f) acetylenes was studied in supercritical carbon dioxide (scCO2) using the easily available complex CpCo(CO)2 as catalyst. The reaction of phenylacetylene produced a mixture of the isomeric cyclotrimers 1,3,5- (2a) and 1,2,4-triphenylbenzene (2a′), in a 1:5 ratio, and traces of cobaltcyclopentadienone complexes CpCo(η4-C4H2[Ph]2CO) (6a, mixture of isomers). The possible product formed by the incorporation of CO2 to alkynes, i.e. diphenylpyrone (7a) was not observed. The reaction of the cobaltacyclopentadiene complex CpCo(1.4-σ-C4[Ph]4)(PPh)3 (8f), in scCO2, was performed. No insertion of CO2 into the Co-C σ-bond to form tetraphenylpyrone (7f) by reductive elimination was observed, instead the cobaltcyclobutadiene complex CpCo(η4-C4[Ph]4) (9f) was formed. In the reactions with other alkynes, lower yields were obtained in general, except in the cyclotrimerisation of the highly activated alkyne, propargyl alcohol (b). Reaction of the non-activated alkynes, 1-hexyne (c) and 3-hexyne (d), produced complex mixtures of cobalt complexes in low yield in which the alkyne was coordinated to cobalt. Finally, the highly hindered diphenylacetylene (f) gave a mixture of the known complexes CpCo(η4-C4[Ph]4) (9f) and CpCo(η4-C4[Ph]4CO) (6f) in agreement with the results observed in conventional organic solvents.

An electron-transfer induced migratory insertion reaction originating from a 19-electron cobaltacyclic anion

The cyclopentadienyl cobaltafluorenyl carbonyl complex Cp(CO)CoC12H8 (3) is reduced in THF in a one-electron irreversible process. The reduction products include the fluorenone radical anion, Fl-, which is proposed to arise through migratory insertion of the CO ligand into the metallacyclic Co-C bond of the 19-electron complex 3-. Electrochemical and IR analyses show that bulk electrolysis under N2 gives 1/3 equiv. each of Fl- and CpCo(CO)2 and 2/3 equiv. of a 17-electron anion [CpCoC12H8]- (2-) Under CO the yield of Fl- is quantitative. The insertion product is also formed when the reduction of the analogous phosphine complex Cp(PPh3)CoC12H8 is performed under CO. An equilibrium between 17- and 19-electron compounds is postulated to account for the synthetic and voltammetric observations. When the cobaltacycle Cp(PPh3)CoC4Ph4 (5) is reduced under carbon monoxide, the CO-insertion product is the π-cyclopentadienone complex CpCo(η4-C4Ph4O) (8). (C) 2000 Elsevier Science S.A.

Low-valent cyanocobaltate chemistry. 3. Reactions of [(η5-C5H5)Co(CN)(CO)]- with electrophiles, nucleophiles, and redox agents. Synthesis of new (η5-cyclopentadienyl)cobalt cyanide complexes

Details of the syntheses and reactivity of (K-crown)[Cp(CN)(CO)] (1a) (crown = 18-crown-6 ether), PPN[Cp(CN)(CO)] (1b), (K-crown)[CpCo(CN)PPh3] (4), and (K-crown)[CpCo(CN)2] (10a) are presented. Compound 1a is readily formed by reaction of CpCo(CO)2 with cyanide in aprotic media. Reaction of CpCo(CO)2 with excess cyanide under forcing conditions results in the dissociation of cyclopentadienide anion instead of [CpCo(CN)2]2- formation. Although the [CpCo(CN)2]2- anion appears to be extremely basic and reactive, an impure form can be isolated by the low-temperature reduction of 10a in DMF. The electrophiles acetyl chloride, benzyl bromide, and methyl fluorosulfate do not react with 1a to form isocyanides but unexpectedly produce CpCo(CO)2 and a variety of Co(II) and Co(III) compounds. The pathways that culminate in these products are suggested to originate from an initial one-electron transfer yielding the intermediate [Cp(CN)(CO)]. Treatment of 1a or 1b with tosyl chloride yields [CpCo-(CN)2(η1-SO2C6H 4CH3)]- and cyanide-bridged cyclopentadienylcobalt(III) polymers, while 1a or 1b reacts cleanly with R3SnCl reagents to form the expected isocyanide complexes. Hg(CN)2 oxidizes 1 to CpCo(CN)3-. Acyl chlorides lacking α-hydrogens react with 1 to produce novel bis(acyl isocyanide) complexes CpCo-(CNCOR)2 in low yields. The spectroscopic characterization of these compounds is presented, and the nature of the cyanide ligand's influence on low-valent metal centers is discussed.

Low-valent cyanocobaltate chemistry. 1. Synthesis, characterization, and reactivity of (K-crown)[CoCp(CO)(CN)]

CoCp(CO)2 (Cp = η5-C5H5) reacts in aprotic solvents with (K-Crown)CN or (PNP)CN to give the novel complexes (K-Crown)[CoCp(CO)(CN)] and (PNP)[CoCp-(CO)(CN)], whose spectroscopic and chemical properties indicate a high electron density on cobalt. In ligand exchange reactions, the cyanide dissociates exclusively, but slowly. The reactivity of the anion is dominated by its electron-transfer ability and basicity rather than its nucleophilicity.

REDUCTIVE SUBSTITUTION OF COBALTOCENE: DISPLACEMENTS OF A CYCLOPENTADIENYL GROUP ON COBALTOCENE AND REPLACEMENT OF SAME BY A DIENE MOIETY

Substitution of a cyclopentadienyl ring of cobaltocene by diene, quinone and cyclopentadienone moieties serves as a synthetic procedure for a series of (η4-ligand)(cyclopentadienyl)cobalt complexes; some speculation as to the involvement of an η1-cyclopentadienyl intermediate in these transformations is advanced.

Cobalt metallacycles. 12. 1 Reaction of cobaltacyclopentadiene with nonacarbonyldiiron and octacarbonyldicobalt. Formation of dinuclear metal complexes

(η-C5H5)(Ph3P)(CoCR 1=CR2CR3=CR-4l (4) reacted wih Fe2(CO)9 or Co2(CO)8 affording dinuclear metal complexes [η-(CO)3(FeCR1=CR2CR3=CR 4)]Co(η-C5H5) (5) or [η-(CO)2(Ph3P)(CoCR1=CR2CR 3=CR4)]-Co(CO)2 (6) and [η-(η-C5H5)(CoCR1..-CR 2..-CR3CHR4)]Co(μ-CO)(CO) 2 (7). The structures of 5b (R1, R4 = Ph; R2, R3 = COOMe) and 7a (R1, R3 = Ph; R2, R4 = COOMe) have been unequivocally determined by single-crystal X-ray crystallography. Complex 5b crystallizes in space group Pbca with Z = 8 and lattice constants of a = 17.264 (3) A?, b = 14.966 (2) A?, c = 19.358 (12) A?, and complex 7a crystallizes in space group P1 with Z = 2 and lattice constants a = 9.890 (2) A?, b = 15.845 (4) A?, c = 8.793 (3) A?, α = 104.36 (3)°, β = 82.24 (3)°, and γ = 103.56 (2)°.