A novel cis-trans isomerism found in a sulfur-bridged Pd2IIAu2I tetranuclear complex with [Pd(amine)2(thiolato)2]-type building units

Treatment of [Au(D-pen-S)(2)](3-) (D-H(2)pen = D-penicillamine) with [PdCl4](2-) in a 1:1 ratio gave a S-bridged (Pd2Au2I)-Au-II tetranuclear complex, in which two square-planar [Pd(D-pen-N,S)(2)](2-) units are linked by two linear Au-I ions. This tetranuclear complex was found to form two geometrical isomers that are discriminated by the cis-trans isomerism of [Pd(D-pen-N,S)(2)](2-) units.