| In this thesis,two kinds of ligands are used to construct lanthanide complexes.The first is to use tetradentate 8-hydroxyquinoline-based acyl hydrazone as main ligand,chloride ion,trifluoromesylate acid ion and?-diketone as co-ligand,which react with Dy?III?ion and result in six complexes.One of them is a mononuclear complex,and the other five dinuclear complexes are derived from the mononuclear complex.The second type ligand is a traditional hexadentate Schiff base compound,which was used to form ten complexes by reacting with hydroxamic acid and lanthanide salt of trifluoromethanesulfonate?Yb,Er and Dy?.The molecular structures of these complexes were determined by X-ray single crystal diffraction analysis.By means of modulating and changing the auxiliary ligands to regular the coordination geometric configurations of central lanthanide rare-earth ions,and consequently tune the magnetic easy axis.These results show that the match between molecule symmetric axis and magnetic easy axis exert a significant effect on the single-molecular magnet performance;In addition,magnostructure relationship of the SMM were further studied by ab initio theoretical calculation.Inerestingly,the Yb analogues show both SMMs and near-infrared luminescent property and their relationship was studied.The main research work of the thesis is as follows:1.Eleven hydrazide type complexes were synthesized:DyCl3HL1?CH3OH?1?,[Dy2Cl4?L1?2?CH3OH?2]?4C5H5N?2?,[Dy2Cl4?L2?2]?2CH3CN?3?,[Dy2?t fo?4?L2?2?EtOH?2]?4?,[Dy2?tta?4?L2?2?EtOH?2]?2?EtOH??5?,[Dy2?dbm?4?L2?2?EtO H?2]?6?,[Gd2Cl4?L1?2?CH3OH?2]?4C5H5N?7?,[Gd2Cl4?L2?2]?2CH3CN?8?,[Gd2?tfo?4?L2?2?EtOH?2]?9?,[Gd2?tta?4?L2?2?EtOH?2]?2?EtOH??10?,[Gd2?dbm?4?L2?2?EtOH?2]?11??HL1=8-hydroxyquinoline-2-carboxaldehyde-?aminourea?hydroc hloride,HL2=8-hydroxyquinoline-2-carboxaldehyde-?benzoyl?hydrazine,tfo=trifl uoromethanesulfonic acid,dbm=dibenzoylmethane,tta=4,4,4-trifluoro-1-?2-thien yl?-1,3-butanedione?.The magnetic measurement shows complexes 1-6 display sig nificant SMMs behavior under the applied field.The ab initio calculation realize d that modification on ligand has a regulating effect on both the local molecular symmetric axis and the magnetic easy axis.2.Based on the traditional Schiff base,with different hydroxamic acid co-li gands,as well as different lanthanide rare-earth metal Yb?III?and Er?III?ions,se ven complexes[ZnL3Yb?CH3O?aca]2?2?CF3SO3??12?,[ZnL3Yb?CH3O?sha]2?2?CF3S O3??2?COH??13?,[ZnL3Yb(bea]2?2?CF3SO3??2?COH??14?,[ZnL3Yb?CH3O?pia]2?2?C F3SO3??2?COH??15?,[ZnL3Yb?CH3O?qua]2?2?CF3SO3??2?CH3CH2OH??16?,[ZnL3Er?CH3O?aca]2?2?CF3SO3??17?,[ZnL3Er?CH3O?sha]2?2?CF3SO3??2?COH??18?,[ZnL3Er?CH3O?bea]2?2?CF3SO3??2?COH??19??L3=N,N?-bis?3-methoxysalicylidene?phenyle ne-1,2-diamine,aca,sha,bea,pia,qua?were sythesized.The molecular magnetic properties of the complexes indicate that the Yb?III?analogues 12-15 displayed obviously SMMs under the applied field,and displayed the near-infrared lu minescent property as well.The gap between ground state and first excited state in the fluorescence emission spectra is comparable with the barrier extracted fro m pure thermally activated orbach process,which offer an efficient method to ge t deep insight in the dynamic magnetic relaxation mechanism.3.Two salen type hetero-nuclear Zn?III?-Dy?III?complexes were synthesized by changing Schiff base ligands.The SMM properties of the complexes 20-21 were studied.?L4=?1E,1'E?-N,N'-?ethane-1,2-diyl?bis?1-?3-methoxy-2-??1-oxidanyl?phenyl?methanimine?,pyz,aca?.It was found that the complexes exhibited obvious SMMs under the zero field behavior. |
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