Reactions of alkyl- and aryl(ferrocenyl)phosphines with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone

Reaction of diphenyl(ferrocenyl)phosphine (1), tri(ferrocenyl)phosphine (2) and tbutyl(diferrocenyl)phosphine (3) with one equivalent of 2,3-dichloro-4,5-dicyano-1,4-benzoquinone (DDQ) yields FcPPh2 • DDQ (4), Fc3P • DDQ (5) and Fc2PtBu • DDQ (6), respectively. Infrared, UV–Vis and ESR spectra of 4–6 are consistent with formation of DDQradical dot− Mössbauer spectroscopy, however, reveals that 4–6 all contain low spin FeII suggesting that the radical cation is ligand centered rather than iron centered.