Oxidation of Nonplanar Nickel Porphyrins
| Autor: | Gang-Lun Fan, 范綱倫 |
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| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 98 In this work, the techniques of NMR, EPR, UV/Vis, and Mass spectroscopy are applied to examine the chemical oxidation products of the two nonplanar nickel porphyrins, nickel(Ⅱ) octaethyltetraphenylporphyrin, (NiⅡ(OETPP)) and nickel(Ⅱ) tetraphenyltetrabenzoporphyrin, (NiⅡ(TPTBP)). DFT theoretical calculation was used to further identify their electron configuration. The results show that oxidation by bromine with more than two oxidation equivalent in the solvent of dichloromethane, the spectra are more in line with the characteristics of single-electron oxidation on porphyrin macrocycle. In contrast, however, in benzene solvent, NiⅡ(OETPP) will undergo two-electron oxidation with bromine in Ni metal ion and porphyrin a1u orbital, respectively. The ground state of two electron oxidation product presents an unusual Ni(III) porphyrin cation radical derivative. According to the investigations of theoretical calculation, Ni(OETPP)Br2 and Ni(OETPP)Br2 were inclined to be dz2,a1uferromagnetically coupled with regard to energetics. Under this electronic configuration, the Fermi contact shifts of 1H and 13C NMR of Ni(Ⅲ) porphyrin cation radical species exhibits the most satisfying linearity with the nuclear spin density, the extracted spin density of nuclear 1s orbital from DFT calculations, than the other combinations of spin coupling states. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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