Spontaneous Reduction of Gold(III) to Gold(I) by Forming Sulfur-Bridged Polynuclear Structure with Octahedral Tris(Thiolato) Complexes

The reaction of fac(S)-[Rh-III(aet)(3)] (aet = 2-aminoethanethiolate) with [(AuCl4)-Cl-III](-) in water gave an S-bridged pentanuclear complex [Au-3(I){Rh-III(aet)(3)}(2)](3+) (1), accompanied by the spontaneous reduction of Au-III to Au-I. The crystal structure of 1(NO3)(3). 4H(2)O was deter mined by X-ray. crystallography. In 1 two octahedral fac(S)-[Rh(aet)(3)] units are linked by three linear Au-I atoms to form a trigonal-bipyramid-type (Rh2Au3I)-Au-III pentanuclear structure with an averaged Au-I-Au-I distance of 3.083(5) Angstrom. The two (Rh2Au3I)-Au-III each other through one Au-I-Au-I interaction with a distance of 3.311(3) Angstrom. The optically active Delta Delta-1 was derived from Delta Delta Delta Delta-[Zn-3(OH){Rh(aet)(3)}(4)](5+) by reacting with [AuCl4](-) in water.