Uni-, bi- and ter-dentate complexes formed from PPh2CH2C(R)NNHC(O)Ph (R = But or Ph) and Pd or Pt: crystal structures of [PdCl{PPh2CH2C(But)NNC(Ph)O}], [Pt{PPh2CHC(Ph)NNC(Ph)O}{PPh2CH2C(Ph)NNHC(O)Ph}] and [Pd{PPh2CHC(But)NHNC(O)Ph}2]

Treatment of the phosphino-N-benzoyl hydrazones PPh2CH2C(R)NNHC(O)Ph (R = But, I; R = Ph, II) with [MCl2(NCPh)2] (M = Pd or Pt) gave complexes of type [MCl{PPh2CH2C(But)NNC(Ph)O}] (M = Pd, 1; M = Pt, 2) containing two fused five-membered chelate rings. Metathesis with LiBr or NaI gave [MX{PPh2CH2C(But)NNC(Ph)O}] (X = Br or I; M = Pd or Pt). The complex [PtMe{PPh2CH2C(But)NNC(Ph)O}] (8) was obtained by treating [PtMe2(cod)] (cod = cycloocta-1,5-diene) with one equivalent of I in hot benzene. Treatment of [PtMe2(cod)] with two equivalents of the phosphine II gave [PtMe{PPh2CH2C(Ph)NNC(O)Ph}{PPh2CH2C(Ph)NNHC(O)Ph] (11), containing a six-membered chelate ring and a unidentate coordinated ligand II. Treatment of [PtCl2(NCMe)2] with two equivalents of II in the presence of triethylamine gave [Pt{PPh2CHC(Ph)N–NC(Ph)O}{PPh2CH2C(Ph)NNHC(O)Ph] (12), containing a terdentate (P,N,O-bonded) doubly deprotonated ene-hydrazone ligand and a unidentate ligand II. Prolonged treatment of [PdCl2(NCPh)2] with two equivalents of I in the presence of triethylamine gave [Pd{PPh2CHC(But)NHNC(O)Ph}2] (13), containing two chelated phosphino ene-hydrazide ligands forming six-membered rings. A similar platinum complex, [Pt{PPh2CHC(But)NHNC(O)Ph}2] (14), was synthesised. The terdentate complexes of [MX{PPh2CH2C(But)NNC(Ph)O}] (M = Pd, Pt; X = Cl, Me) underwent base-promoted (NEt3) Michael-type reactions with MeO2CCCCO2Me to give terdentate complexes of the type [MX{PPh2CH[C(CO2Me)CH(CO2Me)]C(But)NNC(Ph)O}] (M = Pd, Pt; X = Cl, Me). The corresponding bromides and iodides were made by metathesis. The crystal structures of 1, 12 and 13 have been determined.