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Preparation and Some Properties of Tetraamine Cobalt(III) Complexes with Monodentate Thiolate or Sulfinate Ligands

1994; Oxford University Press; Volume: 67; Issue: 2 Linguagem: Inglês

10.1246/bcsj.67.416

1348-0634

Takumi Konno, Hideki Umehara, Ken-ichi Okanoto, Jinsai Hidaka,

Magnetism in coordination complexes

Abstract Tetraamine cobalt(III) complexes with monodentate thiolate ligands, [Co(RS)2(amine)4]+, were newly prepared, where R is CH3 or C2H5 and (amine)4 is bis(ethylenediamine) ((en)2), triethylenetetramine (trien), or tris(2-aminoethylamine) (tren). The (en)2 and trien thiolato complexes selectively formed the cis and cis–α isomers, respectively. The oxidation reactions of [Co(RS)2{(en)2 or (trien)}]+ with use of excess H2O2 gave the corresponding S-bonded sulfinato complexes [Co(RSO2-S)2{(en)2 or (trien)}]+ with retention of the initial geometries, while [Co(CH3SO2-S)2(tren)]+ was not formed by the same oxidation reaction of [Co(CH3S)2(tren)]+. The cis-(en)2 and cis–α-trien complexes were optically resolved by the fractional crystallization or column chromatography. The obtained isomers were characterized on the basis of the absorption, CD, and 13C NMR spectra. The thiolato complexes exhibited absorption spectral changes with time in aqueous solutions, which are ascribed to the replacement of the thiolate ligands by H2O.