Cyclo-octatetraeneiron tricarbonyl

Treatment of q" -l,2,5,6-cyclo-octatetraenecobalt(r -cyclopentadienyl) with methylene iodide and a zinc-copper couple gave the bis-CH2 adduct (209, 19%) whereas similar treatment of r -l,2,3,4-cyclo-octatetraeneiron tricarbonyl gave a mixture of unchanged starting material and ring-expanded adduct (210 25%). ... 

An interesting application of this observation was encountered in the hydrogenation of cyclo-octatetraeneiron tricarbonyl [C8HgFe(CO)3], which was not even partially hydrogenated by a platinum or nickel catalyst. This... 

The addition of protons to some olefin Ti-complexes proceeds smoothly in some cases, while in other cases protonation can be accompanied by structural changes. For example, cyclo-octatetraeneiron tricarbonyl can be protonated in concentrated sulfuric acid without any decomposition. Upon dilution of the reaction mixture the original compound can be recovered. The protonated species is found to contain a bicyclic structure, a bicylo-5,1,0-octane derivative, equation 6-21 A). 

In solution some olefin Ti-complexes have been found to exist in dynamic forms. Cyclo-octatetraeneiron tricarbonyl, (C8H8)Fe(CO)3, serves as an example. The Fe(CO)3 group in this complex shifts about the cyclo-octatetraene ring (Fig. 6-9). 

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