Acta Phys. -Chim. Sin. ›› 1989, Vol. 5 ›› Issue (06): 644-651.doi: 10.3866/PKU.WHXB19890602

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PHOTOCHEMICAL OXIDATION STUDIES OF DINUCLEAR RHODIUM (d7d7) COMPLEXES OF DINITROGEN BRIDGING LIGANDS WITH HALOHYDROCARBONS

Liu Lumei; Bear John L.   

  1. Department of Chemistry; Beijing Normal University; Department of Chemistry; University of Houston

  • Received:1988-03-02 Revised:1988-10-06 Published:1989-12-15
  • Contact: Liu Lumei

Abstract: The photochemical oxidation studies of four Rh_2L_4(d~7—d~7) complexes with RCl were reported for the first time. All of them have different kinds of the dinitrogen bridging ligands:compound 1 and compound 2 are two geometric isomers of Rh_2(ap)_4, ap=2-anilinopyridinate, 2,2-trans and 4,0; compound 3 is Rh_2(dpb)_4, dpb=N, Ndiphenylbensamidinate; compound 4 is Rh_2(dpf)_4, dpf=N, N-dipynylformamidinate. RX are CCl_4, CHCl_3, CH_2Cl_2, C_2H_4Cl_2, C_6H_5Cl and C_6H_4ClCN, respectively. The four complexes of Rh_2L_4(d~7—d~7) complexes undergo a photoinduced halogen abstraction and an one-electron transfer process by irridiation in the visible region. Quantum yields of formation oxidized complexes were determined for the four complexes. It is showed that the quantum yields depend on irradiation wave-length, solvent and axial ligand. Compound 1 is considerably more photochemically active than another compounds. Preliminary flash photolysis studies in the presence of alkyl or aryl halides show that an irreversable electron transfer occurs. However in the presence of nonreactive acceptors such as acetonitrile, reversible electron transfer occurs. However in the presence of nonreactive acceptors such as acetonitrile, reversible electron transfer occurs. Photolysis products were determined by fast atom bombardment mass spectroscopy, and were compared with the electrochemical products. The results of photochemistry were discussed.