Mono- and polynuclear chloro complexes of palladium(II) with α-substituted thioethers

Palladium dichloro bis-benzonitrile reacts with α-substituted thioethers to give the square–planar complexes [PdCl2(RSCH2Z)2] (1–6) (1–4: R=Me, Z=C(O)OMe (1), C(O)OEt (2), C(O)Omenthyl(−) (3), C(O)Me (4); (5): R=Et, Z=C(O)Me; (6): R=Me, Z=CH(OMe)2). Complex 1 crystallizes in the space group P21/a, with Z=2 in an elementary cell whose dimensions are a=9.116(1), b=8.659(1), c=10.351(2) Å and β=112.2(1)°. Its structure (shelxl-93, R1 0.021 and R2w 0.0597) shows a marked deviation from the ideal square geometry to reduce the steric repulsion between the ester group of the sulfur ligand and the chlorine atom in cis position. The one-pot reaction of the chloro complexes 2 or 3 with silver acetate affords the corresponding trimers [Pd3(μ-OAc)3(μ-RSCHZ)3] (7, 8), previously obtained by reacting palladium acetate with MeSCH2Z. Complex 7 undergoes, with KCl or HCl, an OAc−–Cl− exchange reaction to give the two chloro-bridged isomers [PdCl(MeSCHC(O)OEt)]n (9, 10: n=2, 4). The Cl-bridge in dimer 9 is broken by triphenylphosphine to give the monomeric complex [PdCl(MeSCHC(O)OEt)(PPh3)].