Late transition-metal complexes with the heterofunctional phosphine Ph(2)PNHP(O)Ph(2)

The complexes [MCl(cod)(HL)] (M = Rh or Ir), [PdCl(eta(3)-C3H5)(HL)], [PdCl(L-L)(HL)], trans-[RhCl(CO)(HL)(2)] and [AuCl(HL)] have been synthesised by reaction of either [{M(mu-Cl)(cod)}(2)] (M = Rh or Ir, cod = cycloocta-1,5-diene), [{Pd(mu-Cl)(eta(3)-C3H5)}(2)], [{Pd(mu-Cl)(L-L)}(2)] (L-L = C12H12N, C10H8N or C9H12N), [{Rh(mu-Cl)(CO)(2)}(2)] or [AuCl(tht)] (tht = tetrahydrothiophene) with Ph(2)PNHP(O)Ph(2) (HL). In all these complexes the ligand is monodentate P-bound. Chloride abstraction from [PdCl(C12H12N)(HL)] or [PdCl(eta(3)-C3H5)(HL)], using Ag[BF4], gave the cationic compounds [Pd(C12H12N)(HL)][BF4] or [Pd(eta(3)-C3H5)(HL)][BF4] in which the ligand HL is P,O-chelated. Removal of the amine proton in metal complexes of HL (monodentate P-bound) with KOBu(t) afforded a new class of neutral metallacycles incorporating either an MP(2)NO or M(2)P(4)N(2)O(2) framework based on the [Ph(2)PNP(O)Ph(2)](-) (L(-)) ligand. Reaction of [{Pd(mu-Cl)(C9H12N)}(2)] with 4 equivalents of HL in methanol at ambient temperature yielded the neutral palladium(II) complex [PdCl{Ph(2)PNP(O)Ph(2)-P,O}(Ph(2)POMe)] in which one HL ligand has undergone P-N bond scission. The reaction of the iridacycle [Ir(cod){Ph(2)PNP(O)Ph(2)-P,O}] with Mel was shown to proceed with cis addition affording the iridium(nr) metallacyde [IrI(Me)(cod){Ph(2)PNP(O)Ph(2)-P,O}]. All compounds described have been characterised by a combination of P-31-{H-1} NMR spectroscopy, microanalysis and in some cases by H-1 NMR and IR spectroscopy. The molecular structures of four complexes have been determined by single-crystal X-ray diffraction. The metallacycles show pi-electron delocalisation in the P-N-P-O fragment.