Twice the fun: Dimeric FeII diphosphonium bis(alkynyl) complexes are formed by oxidation of the corresponding FeII alkynyl phosphine complexes. The structure of these organometallic diphosphonium salts and their monomeric precursors were established by X‐ray crystallography. The PP bond can be cleaved by two‐electron reduction to regenerate the monomers.

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.

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