Elucidation of the relationship between the molecular structure and reactivity of metalloporphyrins

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The aim of this research project is the elucidation of the reaction mechanism of metalloporphyrins having distorted porphyrin skeleton. The followings were investigated : (1)synthesis and characterization of metallo- porphyrins, (2)reactions concerning to metalloporphyrins in solution, and (3) photochemical reaction.In the present study, 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetraphenylporphyrin and 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin were used as a distorted porphyrin, and the complexes of these porphyrins with Cu(II) and Cr(III) were synthesized and characterized using elemental analysis and various spectrophotometric methods. For Cu(II) complexes, the electron transfer reaction with Cu(II) ion was investigated in acetonitrile, and the effect of the structural deformation of the porphyrin ligand on the electron transfer reaction was discussed based on the self-exchange reaction of metalloporphyrins. Newly synthesized Cr(III) porphyrins were investigated using X-ray absorption technique to obtain information on the properties concerning to ligand substitution and photochemical reactions, and it was revealed that the electronic state of Cr in the complex was in the oxidation state of +3. The ligand substitution reaction of distorted Cr(III)-porphyrins was investigated using spectrophotometric method, and the reaction mechanism elucidated based on the rate law and activation parameters was discussed in the aspect of electronic and steric effect of the substituents on the ligand substitution reactivity.