Easy and quantitative access to Fe(II) and Fe(III) di(aryl)alkynylphosphine oxides featuring [Fe(dppe)Cp*] endgroups: terminal P=O functionality blocks the dimerisation of the Fe(III) derivatives.

A series of paramagnetic di(aryl)alkynylphosphine oxides [PF6] featuring an open-shell [Fe(κ(2)-dppe)(η(5)-C5Me5)](+) endgroup were obtained by oxidation of their neutral Fe(II) parents 3a-c, themselves obtained in a simple and nearly quantitative fashion from the corresponding Fe(II) metallophosphines 1a-c. The new organometallic radicals were characterised by NMR and ESR and were shown to be perfectly stable in solution, in contrast to species such as 1a-b[PF6] which readily dimerise.

Redox-active phosphines: synthesis and crystal structures of palladium(II) complexes of a metallaphosphine in two different oxidation states.

The redox-active metallaphosphine [Fe(dppe)(η(5)-C5Me5)(C≡C-PPh2)] reacts with [Pd(1,5-cod)Cl2] to give mono- and bis-phosphine coordinated palladium centres as a function of stoichiometry, and these complexes provide a stable redox-active platform which allows reversible one-electron {Fe(II)→Fe(III)(+)} oxidations within the palladium coordination sphere.

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.