The 2007 synthesis of the hexamethylpentalene complex cis-(η5,η5-C8Me6)Co2(CO)4 by O’Hare and coworkers makes of interest a theoretical study of the unsubstituted binuclear pentalene cobalt carbonyls (C8H6)Co2(CO)n (n = 6, 5, 4, 3). In this connection an unbridged unsubstituted cis-(η5,η5-C...

Co catalysts supported on γ-Al2O3 were prepared using Co2(CO)6HCCCOOH, Co3(CO)9CCH2COOH, and Co4(CO)10HCCCOOH as precursors. Co(NO3)2 was used as the precursor for preparing the reference catalyst. The results of Fischer-Tropsch synthesis tests and characterization by transmission electron micr...

The reaction of PPh2(C≡CFc) (Fc = Fe(η5-C5H4)(η5-C5H5)) (1) with Fe2(CO)9 (2) and Co2(CO)8 (3) afforded Fe(CO)4(PPh2(C≡CFc)) (4), Fe(CO)3(PPh2(C≡CFc))2 (5), Fe2(CO)6(μ,η2-C≡CFc)(μ-PPh2) (6) (reaction of 1 with 2), PPh2((η2-C≡CFc)Co2(CO)6) (7) and Co2(CO)7(PPh2((η2-C≡CFc)Co2(CO)6)) (...

In this paper, three kinds of hybrid carbonyl cobalt CO-releasing molecules (CORMs), RCOOCH2C2H[Co2(CO)6] (R = NSAIDs-COOH, 1–11; R = celecoxib derivative-COOH, 15), RSO2(R’) CH2C2H[Co2(CO)6] (R = celecoxib, 12; R = nimesulide, 13) and ROCH2C2H[Co2(CO)6] (R = ferulic acid etheyl ester, 14), we...

The recent synthesis by Vidović and Aldridge of the complex (η5-C5H5)2Ru2(CO)4(μ-BF) containing the fluoroborylene ligand (BF), isoelectronic with CO, suggests the possibility of introducing the BF ligand into binuclear cobalt carbonyl derivatives of the type Co2(BF)2(CO)n (n = 7, 6, 5, 4, 3)....

The reaction of tetrafluoroethylene with Co2(CO)8 under mild conditions was reported to give (OC)4CoCF2CF2Co(CO)4. This compound readily undergoes decarbonylation with accompanying fluorine migration to give the trifluoromethylfluorocarbene complex (μ-CF3CF)Co2(CO)6(μ-CO) and eventually the cl...

A series of novel cobalt carbonyl ionic liquids based on 1,1,3,3-tetra-alkyl-guanidine, such as [1,1-dimethyl-3,3-diethylguanidinium][Co(CO)4] (3a), [1,1-dimethyl-3,3-dibutylguanidinium][Co(CO)4] (3b), [1,1-dimethyl-3,3-tetramethyleneguanidinium][Co(CO)4] (3c), and [1,1-dimethyl-3,3-pentamethyle...

Cobalt carbonyl cluster was anchored through a facile route on the surface of organo-functionalized SBA-15 molecular sieve by post-synthetic approach. The successful grafting of organofunctional ligand and cobalt carbonyl cluster was evident thorough 29Si-MAS NMR, 13C-MAS NMR and FT-IR studies. ...

The (C4H4BH)2Co2(CO)n (n = 4, 3, 2, 1) systems have been examined by density functional theory for comparison with the analogous (C4H4BCH3)2Co2(CO)n systems. For the tetracarbonyl (C4H4BH)2Co2(CO)4 a higher energy unbridged structure is found at ∼7 kcal/mol above the lowest energy doubly bridge...

The growing environmental concerns associated with the use of cyanides and their toxicity have led to the prohibition of cyanidation-based gold leaching in many countries, necessitating the search for other extraction methods. Herein, we show that thiosulfate leaching presents an alternative gre...

The ability of some typical gangue minerals and activated carbon to adsorb gold(I) (preg-robbing) in non-ammoniacal thiosulfate solutions was examined at different calcium thiosulfate concentrations. In the absence of calcium thiosulfate, sulfide minerals such as pyrite and chalcopyrite, and car...

Cyanide has been used for more than a century as a preferred lixiviant for extracting gold from ores and concentrates. While cyanide is very effective in treating certain ores and concentrates, it is not suitable for carbonaceous and high copper-bearing ores. Research activities over many decade...

Galena and reference quartz were artificially added into the ammoniacal thiosulfate solution to clarify the role of galena on thiosulfate leaching of gold. The effects of galena on thiosulfate decomposition and gold leaching and the possible effect mechanisms were studied by the thermodynamic ca...

The leaching of gold from a gold concentrate calcine using a novel thiosulfate leaching method that utilizes cobalt-ammonia complex as the oxidant in place of the traditional copper-ammonia catalysis was investigated. The result shows that the thiosulfate consumption can be evidently reduced wit...

Thiosulfate is a promising alternative lixiviant to cyanide for leaching gold from its ores/concentrates due to increased environmental and public concern over the use of poisonous cyanide. However, high thiosulfate consumption and high cost for gold recovery from pregnant solution have limited ...

For carbonaceous gold ore and its concentrates, gold extraction by direct cyanidation is usually low due to the known preg-robbing effect. The leaching behavior of a carbonaceous gold ore with a high content of dolomite in copper-ammonia-thiosulfate solutions was investigated. A gold extraction ...

There are several limitations of thiosulfate leaching methods in its industrial application. The main limitation is the addition of copper and ammonia which act as catalysts in the thiosulfate leaching process. The introduction of cupric ions can accelerate the rate of gold leaching but cause ma...

The catalyzed thiosulfate leach of gold from oxide ores has been evaluated. The addition of fine activated carbon resulted in increased dissolution rates and gold recoveries. It was hypothesized that activated carbon and gold form galvanic couples, and that the rate of oxygen reduction increased...

The electronic spectrum of 2-acetylanthracene in a supersonic free jet reveals the existence of two rotational isomers with ≈ 196 cm−1difference between their S1 origins. In low-temperature rigid glasses, 2-acetylanthracene forms stable dimers. The probable structure of this dimer is also brief...

The first synthesis of the sesquiterpene quinol dasyscyphin E has been achieved starting from cupressic acid. Key steps of the synthetic sequence are the oxidative degradation of the diterpene side chain to give a methylketone, the diastereoselective α-methylation of a protected ketoaldehyde, t...