氰基桥联的Fe2Ni2单分子磁体的合成与磁性

Synthesis and Magnetism of Cyano-bridged Fe2Ni2 Single-Molecule Magnets

利用三氰基构筑单元Bu4N[FeⅢ(PzTp)(CN)3](PzTp=tetrakis(pyrazolyl)borate)和4,4′-二甲氧基-2,2′-联吡啶(4,4′-dmobpy)配体,合成了2例氰基桥联的Fe2^ⅢNi2^Ⅱ四核配合物。单晶X射线衍射表明化合物[FeⅢ(PzTp)(CN)3]2[Ni2^Ⅱ(4,4′-dmobpy)4][FeⅢ(PzTp)(CN)3]2·2CH3OH (1)和[FeⅢ(PzTp)(CN)3]2[Ni2^Ⅱ(4,4′-dmobpy)4](PF6)2(2)具有四核四方形分子结构。直流磁化率测试表明配合物1和2均表现为分子内的铁磁耦合作用。交流磁化率测试表明配合物1和2在零场下具有慢磁弛豫行为,有效能垒分别为12.8和13.0 K。

Two cyano-bridged Fe2Ni2 complexes were synthesized via the reaction of tricyanometallate building block Bu4N[Fe^Ⅲ(PzTp)(CN)3](PzTp=tetrakis(pyrazolyl)borate)and 4,4'-dimethoxy-2,2'-bipyridine(4,4'-dmobpy)ligand.X-ray diffraction study reveals that complexes[Fe^Ⅲ(PzTp)(CN)3]2[Ni2^Ⅱ(4,4'-dmobpy)4][Fe^Ⅲ(PzTp)(CN)3]2·2CH3OH(1)and[Fe^Ⅲ(PzTp)(CN)3]2[Ni2^Ⅱ(4,4'-dmobpy)4](PF6)2(2)exhibit a tetranuclear square structure.Direct current susceptibility measurements indicate that 1 and 2 show intramolecular ferromagnetic interactions between Fe(Ⅲ)and Ni(Ⅱ)ions.Complexes 1 and 2 show the magnetic relaxation property in the absence of dc field,behaving as single-molecule magnets.The fitted relaxation energy barrier Ea/kB for 1 and 2 were 12.8 and 13.0 K,respectively.CCDC:1988983,1;1988982,2.