Mono- and Polynuclear Chloro Complexes of Palladium(II) with a-Substituted Thioethers

Palladium dichloro bis-benzonitrile reacts with alpha-substituted thioethers to give the square-planar complexes [PdCl2(RSCH(2)Z)(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 P2(1)/a, with Z = 2 in an elementary cell whose dimensions are a = 9.116(1), b = 8.659(1), c = 10.351(2) Angstrom and beta = 112.2(1)degrees. Its structure (SHELXL-93, R-1 0.021 and R-2w 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 [Pd-3(mu-OAc)(3)(mu-RSCHZ)(3)] (7, 8), previously obtained by reacting palladium acetate with MeSCH(2)Z. Complex 7 undergoes, with KCI 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 [Pd-Cl(MeSCHC(O)OEt)(PPh3)].