Oxygen Bridge Multicore Iron Complexes

Oxo- , hydroxo- , and alkoxo- bridged multinuclear Iron Complexes have recently received much attention in many respects. Reasons for this phenomenon is that they provide structural models for the active sites of various metalloproteins and nonhene diiron enzyme such as hemerythrin(Hr) , ferritin(Ft) , methane monooxygenase(MMO), ribonucleotide reductase (RNR) .These model complexes can also give us some information for the mechanistic about the reactions of O2 with MMOH and RNR R2. The mode for oxygen bind to the active site of metalloproteins. In addition, Studies about the magnetic behavior of these complexes also play an important role.In 1987, the crystal structures of Hr was determined (Figure 1). this can prove the coordination spheres of Iron is asymmetry.Later, Hartmand and his colleagues succeeded in the synthesis of the complex[Me3TACN(OAc)Fe"]2O by using Me3TACN as the terminal ligand, which had been the first ever synthesized hemerythrin site models. Now the researchs in this field especially in related proteins, have become one focus of inorganic chemistry.In this thesis twelve dinuclear, four tetranuclear complexes with 2, 2' - bipy, phen as ligand and six trinuclear complexes have been synthesized, their structures have been ascertained by CHN element analysis,infared spectrum, UV- vis spectrum.In the infared spectrum of the complexes, there are strong absorptions in -800 cm"1 which can be ascribed to the antisymmetric vibration of the Fe- O - Fe unit indinuclear Iron complexes, which is the same to the date of the metalloproteins. There are strong absorptions in -650 cm-1 which can be ascribed to the Fe4O2 unit in tetranuclear Iron complexes and there are strong absorptions in -610 cm"' which can be ascribed to the Fe3O unit in trinuclear Iron complexes, the different date of antisymmetric vibration and symmetric vibration of CO2- shows two models.In the UV - vis spectrum of the complexes, the absorptions at about 330 nm and 360 nm in dinuclear complexes , the absorptions at about 340 nn"u 406 nm, 467 nm in tetranuclear complexes and the absorptions at about 360 nm 458 nm in trinuclear isresigned to Oxo-> Fe(III) charge transfers.The magnetic susceptibilities result of dinuclear complexes C5oH39Cl3Fc2N8O|7suggests an antiferromagnetic interaction between ions with J= ?199 cm-1, g=2.0. The effective moment of tetranuclear complexes C27H2|ClFe4N4O8 decreases with the temperature, the moment gradually decreases from 4.13 u B at 299.96 K to 0.28 u B at 4.59 K. The date clearly indicate that this complexes possesses an S = 0 ground state. This also suggests an antiferromagnetic interaction between ions.