Model Complexes Of Manganese-Containing Metalloenzyme: Studies On Synthesis, Structure And Properties Of Mn(Ⅲ),Mn(Ⅳ) And Mixed-Valence Multnuclear Manganese Complexes

Manganese multnuclear complexes play a important roles in several biological redox-active systems. In this thesis, 32 new mononuclear and multnuclear manganese complexes have been synthesized at the basis of going over and analysing a great deal of references. Their structures and properties shch as crystal structure, IR spectra, UV-Vis spectra, Cyclic voltammogram, Variable temperature solid state magnetic susceptibility and TG-DSC have been studied in detail. 1.Three types of 5 binuclear manganese complexes with 2,2'-bipy, phen and salicylic acid as ligands have been synthesized, which include 2 mixed-valent manganese complexes. Their structures have been determined and analysized, their UV-Vis spectra and cyclic voltammogram also have been studied. From the results, we see that there are two very strong peaks of UV-Vis spectrum in the range of 400-600 nm, which are similar to those of Mn catalase and Mn ribonuleotide reductase extracted from organisms. The Mn．．．Mn distances in mixed-valent Mn(Ⅲ,Ⅳ) complexes are about the same as those distances found in oxygen evolving complex of PSⅡ. These results are important for understanding the structures of active centers of photosynthetic oxygen-evolving complex, catalase and ribonuleotide reductase.2. 5 mononuclear and 6 binuclear schiff base manganese complexes have been prepared. The crystal structures of 3 complexes haved been determined, and other's structures also have been characterized. Their UV-Vis spectra, cyclic voltammogram and magnetic properties have been studied. The results show that schiff base ligands can drop the potential of manganese and steady high oxide state of manganese, so these complexes can not oxide water and evolving oxygen. At low temperature(40～50K), variable temperature solid state magnetic susceptibility imply the existence of a weak ferromagnetically coupling of MnⅣ2 pairs. 3. 9 trinuclear manganese complexes have been synthesized, including 6 mixed-valent complexes. The crystal structures of 3 complexes haved been determined. Their UV-Vis spectra, IR spectra, cyclic voltammogram and magnetic properties have been studied. The results of their variable temperature solid state magnetic susceptibility show the existence of intramoleculer weak antiferromagnetic interaction, and the difference of couple parameters between the mixed-valent and non-mixed-valent complexes is small, implying the location of the valences of three manganese. 4. 7 tetranuclear manganese complexes have been prepared. Their structures have been characterized by IR spectra, UV-Vis spectra. Their cyclic voltammogram, magnetic properties and the processes of thermal decomposition have been studied. The results show that the structures of these tetranuclear manganese complexes may be a butterfly structure. Their variable temperature solid state magnetic susceptibility show the existence of intramoleculer weak antiferromagnetic interaction at low temperature.