Cobalt carbonyl clusters

Main-group cobalt carbonyl clusters are well known, with neutral clusters such as Sn Co(CO)4 4 and anionic clusters such as [Bi Co(CO)4 4] reported.87 Synthesis proceeds for the former as follows (Equation (3)) ... 

Caution. Decomposition of the cobalt carbonyl clusters produces CO, which is an odorless, toxic gas. The hexane solution of ZnEt2 is convenient to handle, but is a source of ZnEt2, which is a pyrophoric and volatile liquid. Handling these compounds in a well-ventilated hood and wearing eye protection are recommended. 

In those catalysts, the metal species were deposited in the form of salts or carbonyl clusters. Further, the modifications of the oxide surface with the multinuclear cobalt carbonyl cluster Co3(CO)9—CR (R = CH3 or Ph) have been reported (68). 

An octameric cage structure is found for the cobalt carbonyl cluster anchored silanetriol, Co3(CO)9CSi(OH)3 [25]. 

Hydroformylation reactions are important from the industrial point of view and the two commonly used hydroformylation catalysts are either Rh or Co based. We thought it would be interesting to anchor a SiOs unit on a cobalt cluster via hydrosilylation. This would be a close model to a silica-supported cobalt cluster. Secondly, since the reactions of silanetriols have been demonstrated to afford three-dimensional metallasiloxanes, we anticipated that this silanetriol would react with substrates such as trialkylaluminums, affording cobalt carbonyl cluster anchored aluminosiloxanes. Such compounds would resemble a modified zeolite having on its surface catalytically active cobalt carbonyl moieties and might inspire the preparation of actual zeolite systems with these modifications. 

The selective production of methanol and of ethanol by carbon monoxide hydrogenation involving pyrolysed rhodium carbonyl clusters supported on basic or amphoteric oxides, respectively, has been discussed. The nature of the support clearly plays the major role in influencing the ratio of oxygenated products to hydrocarbon products, whereas the nuclearity and charge of the starting rhodium cluster compound are of minor importance. Ichikawa has now extended this work to a study of (CO 4- Hj) reactions in the presence of alkenes and to reactions over catalysts derived from platinum and iridium clusters. Rhodium, bimetallic Rh-Co, and cobalt carbonyl clusters supported on zinc oxide and other basic oxides are active catalysts for the hydro-formylation of ethene and propene at one atm and 90-180°C. Various rhodium carbonyl cluster precursors have been used catalytic activities at about 160vary in the order Rh4(CO)i2 > Rh6(CO)ig > [Rh7(CO)i6] >... 

Cobalt-Catalyzed Hydroformylation and Cobalt Carbonyl Clusters Recent Computational Studies... 

Cobalt-Catalyzed Hydrofoimylation and Cobalt Carbonyl Clusters... 

Ferrocene was the first organometallic guest incorporated and numerous spectroscopic and electrochemical studies have been performed on ferrocene, substituted ferrocene, and related metallocene (e.g. cobaltocene) inclusion complexes (444-469]. Half-sandwich cyclopentadienyl- and benzene-metal carbonyl complexes have also been studied quite extensively [470-479] as have // -allyl metal (palladium) complexes [480], diene metal (rhodium) complexes [481-484], acetylene cobalt carbonyl cluster complexes [485], and complexes with metal carbonyls, e.g. Fe(CO)5, Mn2(CO)io, and CoNO(CO)3 [485a]. 

The use of the cobalt triad carbonyls as catalysts continues to provide many papers for this report. Publications cover the silylformylation of 1-Hexyne catalyzed by diodium-cobalt carbonyl clusters the formation of hydroxycarbene cobalt carbonyl derivatives, the use of rhodium cluster carbonyls in the water-gas shift reaction Rh4(CO) 2> and Co3Rh(CO)] 2 catalysts for the hydrosilation of isoprene, cyclohexanone and cyclohexenone catalytic reduction of NO by CO and the carbonylation of unsaturated compounds The chemistry of iridium carbonyl cluster complexes has been extended by making use of capping reactions with HgCl2and Au(PPh3)Q... 

A number of Pd-Go carbonyl dimers and clusters have been prepared, either by reacting neutral cobalt carbonyl clusters or by anionic cobalt carbonyl metallates with palladium complexes. Treatment of either Pd4(/x-Gl)3-(/i3-GH)(PBu 3)4 or Pd2(/i-X)2(PBu 3)2 with Go2(GO)8 gives the tetranuclear cluster GoPd3(/X3-X)(/x-GO)3-(/X3-G0)(G0)(PBT3)3 48 (X = G1, Br, The M4 core is intermediate between a distorted tetrahedron and a... 

Greenberg S, Clendenning SB, Liu K et al. (2005) Synthesis and hthographic patterning of polycarbosilanes with pendant cobalt carbonyl clusters. Macromolecules 38 2023-2026... 

COMC (1995) provided many examples of clusters up to a C014 carbonyl example. However, as some polynuclear cobalt clusters with more than four atoms have been described during the last decade, the area of large cobalt carbonyl clusters seemed to have been much less investigated during this period of time. Nevertheless, several interesting examples of homometallic cobalt clusters with 5-18 cobalt atoms have been reported. 

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