Tetracobalt dodecacarbonyl

Cobalamin, 25 803 folic acid and, 25 802 Cobalt (Co), 7 207-228. See also Co-base superalloys 60Co isotope 60Co nucleus Fe-Ni-Co alloys Dicobalt octacarbonyl Tetracobalt dodecacarbonyl analysis, 7 215-216 in ceramic-matrix composites, 5 554t coke formation on, 5 266 colloidal suspensions, 7 275 economic aspects, 7 214-215 effect on copper resistivity, 7 676t environmental concerns, 7 216 health and safety factors, 7 216-218 in M-type ferrites, 11 66, 69 occurrence, 7 208... 

G. Bor, U. K. Dietler, P. Pino, A. Poe. Kinetics and Mechanism of the Reaction of Tetracobalt Dodecacarbonyl with Carbon Monoxide under Pressure. J. Organomet. Chem. 1978,154, 301-315. 

Cyclohexylamine, which was one of the best promoters for the stoichiometric reaction, failed to give the catalytic version under the pressure of CO (7 atm). However, Krafft and co-workers used cyclohexylamine coupled with dicobalt octacarbonyl and/or even tetracobalt dodecacarbonyl in DME for a catalytic cyclization. Cyclohexylamine is a relatively sterically bulky amine and is presumed to leave the unsaturated dicobalt species intact and to make CO more labile. ... 

After extraction the catalyst remains in the olefin phase as shown by IR analysis either as an acyl complex, as dicobalt octacarbonyl, or (at low CO pressure) as tetracobalt dodecacarbonyl. 

The synthetic aspects of coordination catalysis still receive far more attention than mechanistic aspects, and precious little can be said with assurance concerning the mechanisms of the foregoing polymerization reactions. Almost the opposite is true of the free radical initiation of vinyl polymerization by metal carbonyls. Bamford et al. (10,11) have studied the kinetics of several such reactions and arrived at plausible interpretations of their results. The initiation of methyl methacrylate polymerization by tetracobalt dodecacarbonyl in the presence of carbon tetrachloride was studied in detail and the results were rationalized in terms of the following mechanism ... 

Note that tetracobalt dodecacarbonyl is a catalyst precursor for reaction at 150 and 10 atm CO. Only 0.01 equiv of the cobalt cluster is required. Actually catalytic amount of Co2(CO)g of high purity is sufficient to complete the intramolecular P-K reaction, also the hexacarbonyldicobalt complex of 2-methyl-3-butyn-2-ol can be decomposed with triethylsilane to generate an active cobalt carbonyl catalyst. ... 

Wei CH, Dahl LF (1966) Molecular structures of triiron dodecacarbonyl and tetracobalt dodecacarbonyl. J Am Chem Soc 88 1821-1822... 

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