Triarylphosphine ligands with pendant electron-rich "[Fe(κ2-dppe)(η5-C5Me5)(C≡C)]-" substituents.

The synthesis of four triaylphosphine ligands featuring electron-rich Fe(II) "Fe(κ(2)-dppe)(η(5)-C5Me5)C≡C-" pendant substituents in para and meta position(s) (1-4) is reported along with that of their corresponding radical cations (1-2[PF6] or 3-4[PF6]3). These triarylphosphines possessing redox-active organometallic substituents constitute a new class of phosphorus-based metallo-ligands. In contrast to many related ferrocenylphosphines, these metallo-ligands are stable and isolable in two redox-states. Their steric and electronic properties are also briefly discussed.