Metallacyclic complexes. Part 2. Synthesis of metallathietane-3,3-dioxide complexes of platinum(II) and palladium(II); the crystal structures of [Pt{CH(COPh)S(O)2CH(COPh)}(PPh3)2]·2CH2CI2 and [Pd{CH(COPh)S(O)2CH(COPh)}(PMePh2)2]·CH2Cl2·H2O

Abstract

The reactions of the complexes cis-[PtCl₂L₂] or trans-[PdCl₂L₂](L = tertiary phosphine or triphenyl phosphite) with bis(benzoylmethyl) sulphone or the dimethyl ester of 2,2′-sulphonyldiacetic acid and an excess of silver(II) oxide in refluxing dichloromethane afford, in high yields, the metallathietane-3,3-dioxide complexes [[graphic omitted]H(COR)}L₂](R = Ph, M = Pt or Pd, L = PPh₃, PMePh₂, PMe₂Ph, PMe₃, PEt₃, or PBuⁿ₃; M = Pt, L = P(OPh)₃; R = OMe, M = Pt or Pd, L = PPh₃). Single-crystal X-ray diffraction studies have been carried out on [[graphic omitted]H(COPh)}(PPh₃)₂]·2CH₂Cl₂, [(6a)] and [[graphic omitted]H(COPh)}(PMePh₂)₂]·CH₂Cl₂·H₂O [(6i)]. Crystals of (6a)·2CH₂Cl₂, are triclinic, space group P, Z= 2, in a unit cell with lattice parameters a= 20.835(2), b= 10.628(2), c= 12.577(4)Å, α= 109.6(1), β= 105.8(1), and γ= 91.4(l)°. The structure was refined to R 0.0595 (R′ 0.0580) for 5 553 reflections having 7 < 2θ < 54°(Mo-K_αX-radiation) collected at room temperature. Crystals of (6i)·CH₂Cl₂·H₂O are triclinic, space group P, Z= 2, in a unit cell with lattice parameters a= 12.985(5), b= 13.93(1), c= 12.057(6)Å, α= 73.71(3), β= 102.61(5), and γ= 100.01 (3)°. The structure was refined to R 0.0745 (R′ 0.0823) for 5 536 reflections having 7 < 2θ < 54° collected at room temperature. Both molecules contain a puckered metallathietane-3,3-dioxide ring [fold angles 15.3(6) for (6a) and 30.2(2)° for (6i)]. The puckering of the four-membered rings, together with the presence of short C–S bonds suggests a heteroallylic contribution to the metallacyclic bonding. N.m.r. data for the metallathietane-3,3-dioxide complexes are also reported.