| Research Abstract |
We have investigated the possibility of the selective formation for the polynuclear complexes, which are given by the reactions of the mononuclear complexes with various metal ions depending on the coordination modes. In this work, firstly, the chromium (III) ions or mononuclear complexes have been selected, since they take unpaired electrons, and poor stability and highly reactivity for the sulfur donor atoms. The selective aggregations of the octahedral chromium (III) complexes around the metal ions are performed and discussed in relation to the unpaired electrons and the interactions between the metal centers. The reactions of the octahedral complexes with the metal ions being the linear-type coordination modes gave stereoselectively the pentanuclear complexes. The reactions of the metal ions being possible for both of the linear-and tetrahedral-type coordination modes can give the pentanuclear and octanuclear complexes, respectively. Further, the cis complexes react with the palladium (II) ion to give the dinuclear complexes and trinuclear or hexanuclear complexes being square-planar complexes and trigonal-bipy-ramidal, whose structures are controlled by the chloride ions. When the square-planar complexes, in which the ligands are less susceptible to substirution of other ligands, reacts with the square-planar complexes, the dinuclear complexes are selectively formed without the hexanuclear complexes. Finally, the fairly stable dinuclear complexes with the disulfide bond are selectively formed by treating with suitable oxidation conditions for the octahedral mononuclear complexes. All of the stereoselectively obtained polynuclear complexes are studied in regard to the sterochemical, spectrochemical, electrochemical, and magnetic properties.
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