双氮桥式配体双核铑(d^7—d^7)络合物与氯代烃光化学氧化反应的研究

PHOTOCHEMICAL OXIDATION STUDIES OF DINUCLEAR RHODIUM (d^7—d^7) COMPLEXES OF DINITROGEN BRIDGING LIGANDS WITH HALOHYDROCARBONS

本文首次报导了双氮桥式配体双铑(d^-—d^7)络合物Rh_2L_4在可见光辐照下与氯代烃发生光化学反应。四种络合物的量子产率皆具有波长依赖性并与溶剂和轴向配体的性质有关。光化学反应产物经快速原子质谱和闪光光解法鉴定。另外,将光化学反应产物和电解产物进行了ESR和循环伏安法的对比测定。结果表明,标题络合物与氯代烃发生不可逆的一电子光诱导转移反应,生成Rh_2L_4Cl。

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 accepters 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.