Synthesis and some properties of T-cage type Co(III)4Hg(II)4 and Rh(III)4Hg(II)4 octanuclear complexes with 2-aminoethanethiolate

The reaction of fac(S)-[M(aet)(3)] (M=Co-III, Rh-III; aet = 2-aminoethanethiolate) with HgO in water produced T-cage type octanuclear complexes, [{M(aet)(3)}(4Hg4O)-O-II](6+) (M=Co-III (1); Rh-III (2)), although a similar reaction with HgCl2 has given only the S-bridged pentanuclear complex. 1 and 2 gave only two isomers, Delta Delta Delta Delta and Lambda Lambda Lambda Lambda, and they were optically resolved. The obtained isomers were characterized on the basis of electronic absorption, circular dichroism (CD), H-1 and C-13 NMR spectral and electrochemical behavior. The Hg(II) atoms in the complex cation take tetrahedral coordination modes and the T-cage type octanuclear structure is formed selectively in the present reaction conditions. The selective formations of the polynuclear complexes with the Hg(II) atoms were discussed in comparison with the corresponding polynuclear complexes with the Zn(II) and Cd(II) atoms.