Synthesis of η⁶-arene complexes of molybdenum containing β-ketophosphine and related P,O mixed donor ligands

The reactions of the ligands Ph₂PCH₂C(O)R (R = Ph, NPh₂) with the η⁶-arene molybdenum complexes [Mo(η³-C₃H₅)(μ-Cl)(η ⁶-C₆H₅R)]₂ (R = H, Me) have been investigated. A series of complexes in which the keto- or amidophosphine acts as a monodentate P ligand or as a neutral or anionic P,O chelating ligand have been synthesised and characterised. The crystal structures of the compounds [Mo(η³-C₃H₅)Cl(η⁶-C ₆H₅Me){Ph₂PCH₂C(O)Ph}], [Mo(η³-C₃H₅){Ph₂PCH ₂C(O)NPh₂-κ²P,O}(η⁶-C ₆H₅Me)][PF₆] and [Mo{Ph₂PCH···C(···O)Ph- κ²P,O}₂(η⁶-C₆H ₅R)] (R = H, Me) have been determined. Interesting di3erences in the reactivity of the ketophosphine ligandversus the amidophosphine ligand were discovered and an unprecedented hydrogen-deuterium exchange of methylene and olefinic protons has been observed for the coordinated neutral or anionic ketophosphine ligands.