SYNTHESIS, MOLECULAR STRUCTURE, SPECTRA AND ELECTROCHEMISTRY OF TWO GEOMETRIC ISOMERS OF TETRAKIS(2-ANILINOPYRIDINATO) DIRHODIUM*

Two gemetric isomers of new dirhodium complex, Rh_2(ap)_4(ap=2-anilinopyridinato),have been synthesixed and isolated. The isomers were characterized by a single-crystal X-ray diffraction analysis. They are 4,0 gemeter (compound 1) and 2,2 trans geometer (compound 2).The radical cations of 1and 2are ESR active. The ESR spectrum of 1+ions, reports that the order of g value is g_⊥>g_e>∥,and the value of g is split into doublet at 77K. This result is consistent with a calculation of the self-consistent-charge discrete variational method. It is shown conclusively that the odd electron is localized on one rhodium. ion with no bound axial ligand, thus giving the first example of true Rh(Ⅱ )—Rh(Ⅲ) complex. The ESR spectrum of 2+ shows g split into a 1:2:1 trilet .In addition, cyclic voltammetry and ESCA of two isomers were detrmined and analyxed. The results indicate that Rh_2(ap)_4 is not only chemically reactive but also sensitive to photochemical oxidation, thus having a wide application in future.

SYNTHESIS, MOLECULAR STRUCTURE, SPECTRA AND ELECTROCHEMISTRY OF TWO GEOMETRIC ISOMERS OF TETRAKIS(2-ANILINOPYRIDINATO) DIRHODIUM*