Polynuclear platinum phosphanido/phosphinito complexes: Formation of P-O and P-O-P bonds through reductive coupling processes

A mixture of the asymmetric complexes of formula [(RF)2Pt(?-Ph2PO)(?-PPh2)Pt(?-PPh2)2Pt(solv)(solv?)] [(1-(solv)(solv?)] (solv, solv? = acetone, H2O, CH3CN) has been prepared by reaction of [(RF)2PtII(?-PPh2)2PtII(?-PPh2)2PtII(NCCH3)2] with AgClO4 in CH3CN/acetone. The lability of the Pt-solvent bonds allows the displacement of the coordinated solvent molecules by dppm or Cl- and the isolation of the tri- or hexanuclear phosphanido/phosphinito Pt(II) complexes [(C6F5)2Pt(?-PPh2)(?-PPh2O)Pt(?-PPh2)2Pt(dppm)] (2) or [NBu4]2[(C6F5)2Pt(?-PPh2)(?-PPh2O)Pt(?-PPh2)2Pt(?-Cl)2Pt(?-PPh2)2Pt(?-PPh2)(?-PPh2O)Pt(C6F5)2] (as a mixture of the two possible isomers 4a and 4b). Complex 2 reacts with AgClO4 to form the tetranuclear derivative [(C6F5)2Pt(?-PPh2)(?-PPh2O)Pt(?-PPh2)2Pt(dppm)Ag(OClO3)] (3), which displays two Pt-Ag donor-acceptor bonds. The mixture of the hexanuclear isomers 4a-4b reacts with Tl(acac) producing the acetylacetonato complex [NBu4][(C6F5)2Pt(?-PPh2)(?-PPh2O)Pt(?-PPh2)2Pt(acac)] (5) which, upon reaction with HCl, yields back the mixture of 4a-4b. The reaction of 4a-4b with PPh3 produces [NBu4][(C6F5)2Pt(?-PPh2)(?-PPh2O)Pt(?-PPh2)2Pt(Cl)(PPh3)] (6) as a mixture of isomers with the chloro ligand located syn (6a) or anti (6b) to the PPh2O- group. Either the reaction of 6 with AgClO4 or the treatment of 5 with HPPh3ClO4 results in the formation of the species [(C6F5)2PtII(?-PPh2)2PtI(?-PPh2OPPh2)PtI(PPh3)] (7) (44 VEC), which can be explained as the consequence of a PPh2O/PPh2 reductive coupling and a rearrangement of ligands in the molecule generating a Pt(II),Pt(I),Pt(I) compound. All complexes were characterised in the solid state by XRD (only one of the isomers, in the cases of 4 and 6) and in solution by NMR spectroscopy.