SYNTHESIS, SPECTRA AND ELECTROCHEMICAL PROPERTIES OF OXYGEN ADDUCTS OF TETRAKIS(2-ANILINOPYRIDINATO) DIRHODIUM COMPLEXES  

作　　者：刘鲁美 胡渝 龚四林 

机构地区：[1]Department of Chemistry, Beijing Normal University, Beijing 100875, PRC

出　　处：《Science China Chemistry》1990年第8期897-904,共8页中国科学（化学英文版）

摘　　要：Two oxygen adducts of different geometric isomers of the tetrakis(μ-2-anilinopyridinato) dirhodium unit, Rh_2(ap)_4^+, have been synthesized and characterized. Rh_2(ap)_4O_2(4,0) is the oxygen adduct 1 of 4, 0 isomer; and Rh_2(ap)_4O_2(2, 2) is the oxygen adduct 2 of 2, 2 isomer. The ESR spectra of both oxygen adducts show that there is a characteristic signal of a superoxide ion, g=2.03. The 4, 0 isomer with different axial ligands gives the order of A_Ⅱ values; O_2^-≈ClO_4^-<Cl^-<CN^-. However, the A_Ⅱ value of the 2, 2 isomer is independent of axial ligands. The half wave potentials E_(1/2)~1 for different axial ligands are: O_2^-<Cl^-<CO, which is consistent with the least A_Ⅱ value of the superoxide. There are plain differences in electrochemical redox process of the two isomers, that is the 2, 2 trans isomer reacting with oxygen involves reversible oxidation, but the oxygen adduct of the 4, 0 isomer is formed irreversibly. The XPS spectrum of the adduct displays a new peak in the region of Ols with low binding energy, 528.7 eV. All characteristict from the spectra show that there is a superoxide group O_2^- in Rh_2(ap)_4O_2 which is dependent on the symmetry of the isomers and bonding ability with oxygen.Two oxygen adducts of different geometric isomers of the tetrakis（μ-2-anilinopyridinato） dirhodium unit, Rh₂（ap）₄⁺, have been synthesized and characterized. Rh₂（ap）₄O₂（4,0） is the oxygen adduct 1 of 4, 0 isomer; and Rh₂（ap）₄O₂（2, 2） is the oxygen adduct 2 of 2, 2 isomer. The ESR spectra of both oxygen adducts show that there is a characteristic signal of a superoxide ion, g=2.03. The 4, 0 isomer with different axial ligands gives the order of A_Ⅱ values; O₂^-≈ClO₄^-&lt;Cl^-&lt;CN^-. However, the A_Ⅱ value of the 2, 2 isomer is independent of axial ligands. The half wave potentials E_1/2¹ for different axial ligands are: O₂^-&lt;Cl^-&lt;CO, which is consistent with the least A_Ⅱ value of the superoxide. There are plain differences in electrochemical redox process of the two isomers, that is the 2, 2 trans isomer reacting with oxygen involves reversible oxidation, but the oxygen adduct of the 4, 0 isomer is formed irreversibly. The XPS spectrum of the adduct displays a new peak in the region of

关 键 词：OXYGEN ADDUCT anilinopyridinato dirhodium complex SPECTRA ELECTROCHEMISTRY 

分 类 号：O6[理学—化学]