Metallacyclic complexes. Part 5. Ligand properties of platinathietane-3-oxide complexes and the single-crystal X-ray structure of [Pt{CH(COPh)S(O)CH(COPh)}(PPh3)2·RhCl(CO)]·CH2Cl2·H2O

Abstract

Treatment of the platinathietane-3-oxide complex [[graphic omitted]H(COPh)}(PPh₃)₂]1a with 1 mol equivalent of either [PdCl₂(cod)](cod = cycloocta-1,5-diene) or trans-[PdCl₂(NCPh)₂] and with 0.5 mol equivalents of [Rh₂(µ-Cl)₂(CO)₄] affords the complexes [[graphic omitted]H(COPh)}(PPh₃)₂·MCI(X)](M = Pd, X = Cl; M = Rh, X = CO), which contain a five-membered [graphic omitted] ring system, formed by co-ordination of the sulphoxide sulphur and the equatorial benzoyl oxygen atom to the metal M. The absence of reaction of 1a with the related labile platinum complexes [PtCl₂(cod)] and cis-[PtCl₂(NCPh)₂] illustrates that the sulphur atom in 1a has relatively poor ligand properties. A single-crystal X-ray diffraction study has been carried out on [[graphic omitted]H(COPh)}(PPh₃)₂·RhCl(CO)]·CH₂Cl₂·H₂O, 3. Crystals are triclinic, space group P, Z= 2, in a unit cell with lattice parameters a= 11.761(17), b= 20.701(18), c= 13.006(16)Å, α= 102.8(3), β= 124.7(3) and γ= 88.4(2)°. The structure was refined to R 0.0600 (R′ 0.0559) for 5105 reflections having 7 < 2θ < 54° collected at room temperture. It bears a strong resemblance to that of complex 1a, but there are several differences which are discussed.