以双亚甲胺席夫碱为配体的双核吡唑铜配合物的磁性理论研究

Theoretical studies on magnetic properties of a dinuclear copper(Ⅱ) complex with schiffbase ligand

采用对称性破损态方法结合密度泛函理论,以双亚甲胺席夫碱为配体的双核吡唑铜配合物[Cu_2L(PZ)](L=双甲亚胺三阴离子,由1-苯基-3-甲基-4-甲酰吡唑和1,3-二氨-2-丙醇衍生而成;PZ=吡唑阴离子)作为研究对象,通过与实验数据相比较,讨论了不同密度泛函方法与基组对金属铜配合物磁交换耦合常数的影响.结果表明,4种混合密度泛函方法(B3PW91,B3LYP,B3P86和PBE)及3种单一密度泛函方法(BPW91,BLYP和BP86)的计算结果都能与实验值符号一致,且B3P86方法所得到的结果与实验值最为接近,而单一密度泛函的计算结果误差较大,与实验值吻合程度不好.同时采用B3P86方法计算所得交换耦合常数Jab对基组的依赖性较大.研究表明,2个Cu(Ⅱ)离子之间弱的反铁磁相互作用主要源于单占据分子轨道SOMOs小的能量劈裂.

In the present work, the magnetic properties of antiferromagnetic complex [Cu2L（PZ）] has been investigated on the basis of density functional theory（DFT） with the broken symmetry（BS） approach. The computational results of the hybrid density functional theory（B3PW91, B3 LYP, B3P86 and PBE） and single density functional theory（BPW91, BLYP and BP86） are in good agreement with the negative sign of experimental value, and the result of B3P86 calculation method is closer to the experimental one, and has a large depenence on the basis set. To the dinuclear copper complex, B3P86/LANL2 DZ shows a significant improvement in exchange coupling constants with the experimental data.