| Summary: | 博士 === 國立成功大學 === 化學系 === 90 === Abstract
The research performed in this works constitutes four major parts. The synthetic methods of Rh(III) and Ir(III) complexes coordinated with various ligands including 1,10-phenanthroline (phen), 2,2''-bipyridine (bipy), 2,2''-dipyridyl-amine (HDPA), 2-pyridyl N-methyl-2-imidazolyl ketone (pik), di-2-pyridyl ketone (dpk), phenyl-pyridin-2-ylmethylene-amine (PA) or 2-(arylazo)pyridine (Azpy) are given in the first part. These compounds are characterized by NMR spectroscopic techniques. Compared with analogous studies in the literature, it has been found that our synthetic routes are more efficient and simplified. The study performed here, therefore, provides valuable information for chemists interested in synthesis of complexes coordinated with mixed ligands.
The photophysical and electrochemical studies, as well as the synthetic work, of cis-[Rh(pik)2Cl2] + are contained in the second part. The same studies performed on cis-[Rh(dpk)2Cl2]+, cis-[Rh(dpk)(phen)Cl2] + and cis-[Rh(dpk)- (bipy)Cl2]+ are given in the third part of this research. The compositions and conformer elucidations are accomplished by MS、IR、and NMR spectroscopic methods. Absorption, emission and polarization spectra of all these complexes are examined in detail to confirm the transition types and orbitals involved in the transition. Electrochemical experiments including cyclic voltammetry (CV) and controlled-potential electrolysis (CPE) have also been carried out to acquire supplementary and complementary information. The sites that accommodate electrons in electrochemical reactions are also thoroughly discussed.
The last part is focused on the Ir(bzpy)(phen)Cl2 (bzpy = ortho-C- deprotonated form of 2-benzoylpyridine) complex. Through MS, IR and NMR spectroscopies studies, we infer that (1) the bzpy ligand is attached to the metal ion with the N-C- coordination pattern and (2) the complex exhibits the cis-a conformation. This complex shows apparent absorption in the UV-vis region which is classified as the ligand pp* transition. The medium-intensity absorption observed in 25~28 kK is assigned as spin-allowed CT transition. The emission behavior observed at low temperature (77K) of this complex originated from linear oscillators according to the values of polarization obtained by excitation-polarization spectra. Electrochemical studies of this complex have also been undertaken. It is noteworthy that the electron transition can be verified via SBLCT (σbond to ligand charge transfer) mechanism, which cannot be distinguished by electronic spectroscopy alone.
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