| Research Abstract |
(1) Design and Preparation of Tetranuclear Manganese Complexes for the Models of Manganese Clusters Involved in Oxygen Evolving Center (OEC) in Photo-system II : Novel tetranuclear manganese complexes with 1, 3-Bis[bis (2-pyridyl-methyl) amino]-2-propanol (Htpdp) and 1, 5-Bis[bis (2-pyridylmethyl) amino]-3-pentanol (Htmdp) were newly prepared and their structures were clarified. The complexes are characteristic of having two di (mu- oxo) Mn_2 (III, IV) units. Especially, the latter tmdp complex contains two water molecules in close proximity to the di (mu-oxo) Mn_2 (III, IV) units. Therefore, the complex is worth noting sa effective model for the tetranuclear manganese clusters involved in OEC.
(2) Preparation of Dinuclear Cobalt and Iron Complexes Which Reversibly React with Molecular Oxygen : The dinuclear cobalt (II, II) complex [Co_2 (tpdp or tmdp) (CH_3COO)]^<2+> was newly prepared. The complex was found to react with molecular oxygen to form mu -peroxo complex. In addition, the dinuclear iron (II, II) complex containing N, N, N', N'-Tetrakis[2-(6-methylpyridyl) methyl]-1, 3-diamino-propane-2-ol (6Me-Htpdp) was newly prepared. The complex is very interesting in that it reversibly reacts with molecular oxygen at -20ﾟC. We are trying to prepare the oxygen complex which can be isolated even under ambient conditions.
(3) Thermal Reactions of Solid Metal Complexes : For the construction of novel multinuclear metal complexes, a new solid-phase synthetic method must be developed in addition to usual liquid-phase method. To do this, the solid-phase thermal reactions of various metal complexes should be fully understood. The structural changes (especially isomerization) of a variety of nickel (II), cobalt(III), and chromium (III) complexes were investigated. The results obtained in the present study will give fundamental data for the development of a new synthetic method.
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