Synthesis and reactivity of phosphanido bridged 1,1′-bis(diphenylphosphino)ferrocene complexes [(RF)2Pt(μ-PPh2)2M(dppf)] [M = Pt, Pd]

Hetero-trinuclear complexes of formula [(C6F5)2Pt(μ-PPh2)2M(dppf)] [dppf = 1,1′-bis(diphenylphosphino)ferrocene, M = Pt (1), M = Pd (2)] were prepared by coupling between cis-[(C6F5)2Pt(PPh2)2]Li2 and cis-MCl2(dppf). Reaction of the Pt/Pt/Fe species 1 with [Ag(OClO3)(PPh3)] or I2 resulted in the formation of the complexes [(C6F5)(PPh3)Pt(μ-PPh2)2Pt(dppf)] (3) and [(C6F5)(I)Pt(μ-PPh2)2Pt(dppf)] (4), respectively, in which one of the pentafluorophenyl ligands has been replaced by PPh3 or I. Reaction of the Pt/Pd/Fe species 2 with Ag(ClO4) afforded the tetranuclear complex [(C6F5)2Pt(μ-PPh2)2Pd(dppf)Ag] (5) where the silver atom is bonded to Pd, to one of the bridging P and to one of the dppf P atoms. With [Ag(OClO3)(PPh3)], complex 5 is also formed, although mixed with [Ag(PPh3)2][ClO4]. A dynamic process in solution, in which the silver atom passes from one Pd–μPPh2 bond to the other, has been observed at room temperature for complex 5. The crystal structures of 3, 4 and 5 are reported.