Tetraphenylcyclobutadiene iron tricarbonyl

R. P. Dodge, and V. Schomaker, Crystal Structure of Tetraphenylcyclobutadiene Iron Tricarbonyl, Nature 186, 798-799 (1960). 

Although a metal exchange reaction is not often thought of as a preparative method, such reactions can be useful since they generally proceed in good yield. Palladium is replaced by iron (2-8) by conversion of tetraphenylcyclo-butadiene palladium dibromide to tetraphenylcyclobutadiene iron tricarbonyl. The driving force involves the formation of the more stable tetraphenylcyclobutadiene iron tricarbonyl complex. 

Orgel (23). Subsequently, Hubei and co-workers (24) obtained, among other products, tricarbonyl-7r-tetraphenylcyclobutadiene iron by the reaction of tolane with iron carbonyls. More recently, a general synthesis of tetra-phenylcyclobutadiene-metal complexes using ligand transfer from tetra-phenylcyclobutadiene palladium(II) halides (25) to a metal carbonyl has been described (26). It is also possible to obtain complexes containing... 

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