Mono- or polynuclear surface species: Models and tendencies with cobalt and rhodium
摘要:
Models of surface reactions of cobalt and rhodium carbonyls with oxide or thiolate type supports were prepared and characterized. For Co carbonyls it was found that simple noncarbonyl ligands that can be formed in reductive CO reactions may promote clusterification under conditions where the support alone causes declusterification. Model complexes of the interaction of rhodium with silica and aromatic thiolate supports were structurally characterized by X-ray diffraction. Model compounds indicate that organic thiolate supports promote clusterification with cobalt and declusterification with rhodium.
The preparation of acyltetracarbonylcobalt compounds from ketenes and hydridotetracarbonylcobalt
作者:Ferenc Ungvary
DOI:10.1016/0022-328x(86)80136-x
日期:1986.4
Ketenes (R1R2CCO, R1, R2 = H or alkyl) react rapidly at −79°C with hydridotetracarbonylcobalt in a 11 molar ratio to form quantitatively the corresponding acyltetracarbonylcobalts, which can be isolated in good to excellent yields. Electron-withdrawing substituents in the ketene lower the reactivity towards HCo(CO)4.
Oxidative addition of Co(COMe)(CO)4 and MoMeCp(CO)3 to Pd(dba)2 (dba = dibenzylideneacetone) in the presence of the bidentate ligand L2 (L2 = dppe (1,2-bis(diphenylphosphino)ethane), tmeda (N,N,N‘,N‘-tetramethylethylenediamine), bpy (2,2‘-bipyridine), phen (1,10-phenanthroline)) takes place to give L2(MeCO)Pd−Co(CO)4 (L2 = dppe (1), tmeda (2), bpy (3), phen (4)) and (dppe)MePd−MoCp(CO)3 (5), respectively
Intermediate Complexes in the Octacarbonyl Dicobalt-Initiated Living Polymerization of 3-Methyl-1,2-butadiene
作者:Judit Sóvágó、M. Gary Newton、Evgenia A. Mushina、Ferenc Ungváry
DOI:10.1021/ja9542404
日期:1996.1.1
2-butadiene at room temperature dinuclear η3-allyl-type complexes are formed which contain 2 + n (n = 0, 1, 2, 3, ···) five-carbon units depending on the applied molar ratio. These complexes are the individual compounds in the octacarbonyl dicobalt-initiated living polymerization of 3-methyl-1,2-butadiene. The first three members in this series of complexes containing two (1), three (2), and four (3) five-carbon
Mechanistic Studies of the Copolymerization Reaction of Aziridines and Carbon Monoxide to Produce Poly-β-peptoids
作者:Donald J. Darensbourg、Andrea L. Phelps、Nathalie Le Gall、Li Jia
DOI:10.1021/ja046225h
日期:2004.10.1
The coupling of carbonmonoxide and aziridines has been shown to be selective for comonomer-alternating enchainment in the presence of PhCH2C(O)Co(CO)4 to afford poly-beta-peptoids. In this article, we have investigated the mechanistic aspects of the reaction of CO and N-butylaziridine by means of in situ infrared spectroscopy employing CH3C(O)Co(CO)3L (L = PPh3 (1) and P(o-tolyl)3 (2)) as precatalysts
O-Silylation of acylcobalt tetracarbonyls, RC(O)Co(CO)4, gives the dinuclear carbene complexes [µ2-RC(OSiR′3)}(µ2-CO)Co2(CO)6], of which one derivative (R = Me, R′= Ph) was characterized by X-ray diffraction.