Synthesis,Crystal Structure And Magnetic Properties Of Mononuclear And Grid-like Transition Metal Complexes

The main work of this thesis is the synthesis, stucture and magnetic properties of mononuclear and grid-like transiton metal compounds. according to the literatures, we get some easily synthesized and N4O2coordination environment ligands with high yields, using pyrimidine as bridging group. Using the ligands, we get a tetranuclear Feâ…¢ compound. On the basis of the N4O2coordination environment ligands,we get some N2O coordination environment ligands.Then three mononuclear and one dinuclear Feâ…¢ and one mononuclear Coâ…¡ complexes are synthesized. We also synthesized a mononuclear Feâ…¢ complex by using3,6-dibromopyrazine as the precursor of the ligand. We find the compound3have imcomplete spin crossover phenomenon. By comparison the mononuclear and grid-like complexes, we can get some information of the effect of the magnetism of different framework. The effect of solvent for some compounds have also been studied. The main conclusions are as followed:Firstly, one pyrimidine bridged tetranuclear Feâ…¢ compound with N4O2coordinative environment Feâ…¢ compound have been synthesized, the compound have high spin crossover quality. Adjacent Feâ…¢ ions are weakly antiferromagnetically coupled via pyrimidine ligand,with coupling constant J=-1.26cm-1.Seconly, four mononuclear Feâ…¢ and one dinuclear compounds are synthesized by using the tridentate ligands. we find that the compound2is high spin crossover state, it only use half coupling atoms to couple with the Feâ…¢. Magnetic susceptibility of complexes3have imcomplete spin crossover quality. In complex4, adjacent Feâ…¢ ions are weakly antiferromagnetically. Complex5is a mathanol bridged symmetrical Feâ…¢ compound and we also get a mononuclear Coâ…¡ complex. We also get a mononuclear Feâ…¢ complex by using3,6-dibromopyrazine as the precursor of the ligand.Thirdly, find a mature method to get N2O coordination environment tridentate ligands. In some conditions,we can get different substitute mononuclear Feâ…¢ compounds. Then we can do some research of the impact of the framework between the mononuclear and grid-like Fe3+compounds...