Hydrolytic disproportionation of coordinated white phosphorus in [CpRu(dppe)(η1-P4)]PF6 [dppe = 1,2-bis(diphenylphosphino)ethane]

The reaction of [CpRu(dppe)Cl] (1), dppe = 1,2-bis(diphenylphosphino)ethane, with one equivalent of P4 in the presence of TlPF6 affords the stable complex [CpRu(dppe)(η1-P4)]PF6 (2) which contains the tetrahedral P4 molecule η1-bound to the metal. The tetraphosphorus ligand readily reacts with water upon mixing acetone or THF solutions of the complex with excess water. The complexes [CpRu(dppe)(PH3)]PF6 (5) and [CpRu(dppe){P(OH)3}]PF6 (6), identified among the hydrolysis products, contain the PH3 molecule and, respectively, the unstable P(OH)3 tautomer of the phosphorous acid bound to the CpRu(dppe) fragment. In CH2Cl2 the coordinated P(OH)3 molecule in 6 easily yields the compound [CpRu(dppe){PF(OH)2}]PF2O2 (8), via hydrolysis of the hexafluorophosphate anion and F/OH substitution in the coordinated P(OH)3 molecule. All the compounds have been characterized by elemental analyses and NMR measurements. The crystal structures of 2 and 8 have been determined by X-ray diffraction methods.