基于三氰基铁(Ⅲ)酸盐的Fe^(Ⅲ)_(4)Ni^(Ⅱ)_(2)六核配合物的合成、结构及磁性

Synthesis,crystal structure,and magnetic properties of a cyanide‑bridged Fe^(Ⅲ)_(4)Ni^(Ⅱ)_(2) hexa‑nuclear complex based on tricyanideferrate(Ⅲ)

利用三氰基铁酸盐(Bu_(4)N)[FeⅢ(Tp)(CN)_(3)](Tp=氢化三(1-吡唑基)硼酸)与配体2,9-二吡唑基-1,10-菲咯啉(dpzpen)以及高氯酸镍反应合成了一例氰根桥联的Fe^(Ⅲ)_(4)Ni^(Ⅱ)_(2)六核配合物[Fe_(4)Ni_(2)(Tp)_(4)(CN)_(12)(dpzpen)_(2)]·12H_(2)O·3CH_(3)OH (1)。结构研究表明配合物1具有近似菱形的Fe^(Ⅲ)_(2)Ni^(Ⅱ)_(2)骨架结构,另外2个Fe则通过氰根延伸在菱形的外侧。磁性研究表明在配合物1中氰根桥联的Fe和Ni表现出铁磁相互作用。更为重要的是,基于配合物1的结构模型,对它的变温磁化率数据进行拟合得到了不同Fe-Ni之间的磁耦合常数,得到的最佳磁耦合常数J3d(15.73 cm^(-1))>J2d(3.53 cm^(-1))≈J1d(3.50 cm^(-1))与Ni-N键的键长以及Ni-N≡C键角的变化趋势有关(J3d:0.206 5 nm,169.8°;J2d:0.206 2 nm,163.1°;J1d:0.198 7 nm,161.6°)。以上结果表明Ni-N键长越短,Ni-N≡C键角越大,Fe与Ni之间的铁磁耦合越强。

A cyanide-bridged Fe^(Ⅲ)_(4)Ni^(Ⅱ)_(2) hexa-nuclear complex[Fe_(4)Ni_(2)(Tp)_(4)(CN)_(12)(dpzpen)_(2)]·12H_(2)O·3CH_(3)OH(1)(Tp=hydrotris(pyrazolyl)borate,dpzpen=2,9-di(pyrazo-1-yl)-1,10-phenanthroline)was prepared by the reaction of tri-cyanideferrate􀃮(Bu_(4)N)[Fe^(Ⅲ)(Tp)(CN)_(3)]with ligand dpzpen and Ni^(Ⅱ)salt.Structural analysis indicates that two[FeⅢ(Tp)(CN)_(3)]-units bridge two[Ni^(Ⅱ)(dpzpen)]^(2+)fragments forming an approximately rhombic Fe^(Ⅲ)_(2)Ni^(Ⅱ)_(2) skeleton with another two[Fe^(Ⅲ)(Tp)(CN)_(3)]-hanging outside the rhombus through cyanide bridges.Magnetic studies show that complex 1 exhibits ferromagnetic interaction between Fe^(Ⅲ)and Ni^(Ⅱ)through cyanide groups.More significantly,the magnetic-structural relationship of complex 1 was established by fitting the temperature dependence of magnetic susceptibility based on its structural model.The best-fitting parameters J3d(15.73 cm^(-1))>J_(2d)(3.53 cm^(-1))≈J_(1d)(3.50 cm^(-1))were in good agreement with the variation tendency of corresponding Ni-N bond lengths and Ni-N≡C angles(J_(3d):0.2065 nm,169.8°;J_(2d):0.2062 nm,163.1°;J_(1d):0.1987 nm,161.6°),indicating a shorter Ni-N bond length and a larger Ni-N≡C angle in favor of ferromagnetic interaction for cyanide-bridged Fe^(Ⅲ)-Ni^(Ⅱ)system.CCDC:2239885.