Dicarbon monoxide explained

Dicarbon monoxide is a molecule that contains two carbon atoms and one oxygen atom. It is a linear molecule that, because of its simplicity, is of interest in a variety of areas. It is, however, so extremely reactive that it is not encountered in everyday life. It is classified as a carbene, cumulene and an oxocarbon.^[1]

Occurrence

Dicarbon monoxide is a product of the photolysis of carbon suboxide:^{[2] [3]}

C₃O₂ → CO + C₂O

It is stable enough to observe reactions with NO and NO₂.^[4]

Called ketenylidene in organometallic chemistry, it is a ligand observed in metal carbonyl clusters, e.g. [OC₂Co₃(CO)₉]⁺. Ketenylidenes are proposed as intermediates in the chain growth mechanism of the Fischer-Tropsch Process, which converts carbon monoxide and hydrogen to hydrocarbon fuels.^[5]

The organophosphorus compound (C₆H₅)₃PCCO (CAS# 15596-07-3) contains the C₂O functionality. Sometimes called Bestmann's Ylide, it is a yellow solid.^[6]

Notes and References

1. Frenking, Gernot; Tonner, Ralf "Divalent carbon(0) compounds" Pure and Applied Chemistry 2009, vol. 81, pp. 597-614.
2. Bayes, K. . Photolysis of Carbon Suboxide . . 83 . 1961 . 17 . 3712–3713 . 10.1021/ja01478a033 .
3. Anderson, D. J. . Rosenfeld, R. N. . Photodissociation of Carbon Suboxide . . 94 . 1991 . 12 . 7857–7867 . 10.1063/1.460121 .
4. Thweatt, W. D. . Erickson, M. A. . Hershberger, J. F. . Kinetics of the CCO + NO and CCO + NO₂ reactions . . 2004 . 108 . 1 . 74–79 . 10.1021/jp0304125 . 2004JPCA..108...74T .
5. Jensen, Michael P.; Shriver, Duward F. "Carbon-carbon and carbonyl transformations in ketenylidene cluster compounds" Journal of Molecular Catalysis 1992, vol. 74, pp. 73-84.
6. H. J. Bestmann, R. Zimmermann, M. Riou "Ketenylidenetriphenylphosphorane" e-EROS Encyclopedia of Reagents for Organic Synthesis 2001.