Does cyclopentadienylirondicarbonyl dimer have a metal-metal bond? Who's asking?

Abstract

Since its first synthesis in the early 1950s, the carbonyl-bridged dimer [CpFe(CO)_2]_2 has almost always been depicted with an explicit Fe-Fe bond (Figure 1a). In a recent article (Chem. Commun. (2012) 11481-11503), Green, Green and Parkin characterize that as a misrepresentation, and recommend that the mol. be shown as in Figure 2b. I will offer arguments for the traditional representation, with the Fe-Fe bond, as more appropriate in most situations. I will further suggest that the choice of how best to represent a mol. will generally be context-dependent, and support that claim by comparison to the process of translation between languages.

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