Ferrole


In organoiron chemistry, a ferrole is a type of diiron complex containing the 3FeC4R4 heterocycle that is pi-bonded to a Fe3 group. These compounds have Fe-Fe bonds and semi-bridging CO ligands. They are typically air-stable, soluble in nonpolar solvents, and red-orange in color.

Synthesis

Ferroles typically arise by the reaction of alkynes with iron carbonyls. Such reactions are known to generate many products, e.g. complexes of cyclopentadienones and para-quinones.
Another route involves the desulfurization of thiophenes by iron carbonyls, shown in the following idealized equation:
An unusual route to ferroles involves treatment of Collman's reagent with trimethylsilyl chloride :

Reactions

Some ferroles react with tertiary phosphines to give the substituted flyover complex Fe25.