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

Abstract

The reactions of the ligands Ph₂PCH₂C(O)R (R = Ph, NPh₂) with the η⁶-arene molybdenum complexes [Mo(η³-C₃H₅)(μ-Cl)(η⁶-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-C₆H₅Me){Ph₂PCH₂C(O)Ph}], [Mo(η³-C₃H₅){Ph₂PCH₂C(O)NPh₂-κ²P,O}(η⁶-C₆H₅Me)][PF₆] and [Mo{Ph₂PCHC(O)Ph-κ²P,O}₂(η⁶-C₆H₅R)] (R = H, Me) have been determined. Interesting differences in the reactivity of the ketophosphine ligand versus 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.