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JP12

Quantum Mechanical Calculation of Structurally Distorted Metal Complex - Structural Optimization of Octahedral Cobalt(III) Complexes with a Carbonato Ligand -

○Toshiaki Taura（Faculty of Information Science and Technology, University of Aichi Prefecture），Tomokazu Kobayashi（Faculty of Information Science and Technology, University of Aichi Prefecture），Kanako Tachi（Faculty of Information Science and Technology, University of Aichi Prefecture）

The d6 cobalt(III) complex does not display a striking structural deformation from octahedral geometry. One of the exceptions is the cobalt(III) carbonato complex with a cabonato chelate, which shows a great deviation of the O-Co-O bond angle of 70 degree from the octahedral one (90 degree). This is due to the steric restriction of the chelate carbonato ligand of a four membered ring. This deformation should supply some strain for the cobalt(III) complex and influence the structure around the cobalt ion and the reactivity concerning this complex. From this viewpoint, some experimental approaches have already been carried out. One of the examples is the trans influence of a chelated carbonato. Any distinct influence was not detected in the Co-N bond length trans to the Co-O bond but the N-Co-N bond angle trans to the O-Co-O angle becomes larger than the octahedral angle (90 degree). In this work, we determined the structures, bond lengths and angles for several carbona to cobalt(III) complexes by using the DFT calclation at B3LYP/6-31G* level. After comparing the DFT and X-ray structures of these complexes, we discussed about the calculation reliability of this method for the cobalt(III) complexes having a strain in the structure.