SYNTHESES AND SOME PROPERTIES OF S-BRIDGED PENTANUCLEAR CO(III)-HG(II) OR RH(III)-HG(II) COMPLEXES WITH 2-AMINOETHANETHIOLATE - CRYSTAL-STRUCTURES OF [(RH(AET)(3))(2)(HGCL2)(3)] AND [(RH(AET)(3))(2)(HG-3))(NO3)(4)](NO3)(2)

S-Bridged pentanuclear complexes [{Rh(aet)(3)}(2)(HgCl2)(3)] (1) and [ {M(aet)(3)}Hg-2(3)(NO3)(4)](2+) (M=Rh(III), 2 and Co(III), 3) were new ly prepared by the reaction of fac(S)-[M(aet)(3)] with HgCl2 or Hg(NO3 )(2); where aet denotes 2-aminoethanethiolate. The crystal structures of I and 2 were determined by X-ray diffraction methods. These complex es consist of two fac(S)-[M(aet)(3)] subunits, three Hg atoms, six chl orides (for 1) or nitrates (for 2), and water molecules, in which the configuration of the five metals is an approximately regular trigonal- bipyramid. Each Hg atom in these complexes takes a highly distorted te trahedral geometry. There are three kinds of nitrates in [{Rh(aet)(3)} Hg-2(3)(NO3)(4)](NO3)(2), bridged bidentate, monodentate, and anion. B oth 1 and 2 possess a novel chirality due to the helical structures of three Rh-S-Hg-S-Rh chains. Although 1 was insoluble in water, 2 and 3 were optically resolved by fractional precipitation. These complexes were characterized by their absorption, CD, and NMR spectra. The coord inated nitrates in 2 and 3 were readily replaced by water molecules wh en dissolved in water. The stabilities of the S-bridged pentanuclear c omplexes are also discussed.