A detailed study of the synthesis of (η-arene)(η-cyclopentadienyl)iron(II) hexafluorophosphates has been made using microwave dielectric heating. Reactions were carried out in a conventional 850 W microwave oven in a very simple solid CO₂-cooled apparatus. A wide range of arene ligands were used. The microwave technique reduced the normal reaction times for the AlCl₃-mediated ligand exchange with ferrocene (with aluminium powder to prevent ferricinium ion formation) from several hours to a few minutes and generally resulted in higher yields. 1,2,4-Trichlorobenzene was found to be an excellent solvent for such reactions. A preliminary survey of the efficacy of the type of the metal powder used revealed that zinc and copper were as effective as aluminium, but that nickel and tin gave little or no reaction. Better yields were usually obtained when an excess of ferrocene was used. This was particularly true of alkylarene ligands where almost quantitative yields were obtained in some cases. The microwave method is particularly suited to the synthesis of bis and more highly complexed species. Arylamine complexes can also be made in high yields. Complexes of triphenylphosphine are reported together with a wide range of other arenes.

Decomplexation of these complexes can be efficiently achieved by a slight variant of the above microwave procedure. High yields of free ligand were obtained by irradiating an admixture of the complexes with flaked graphite.