Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, PR China.
Dalton Trans. 2010 Nov 14;39(42):10249-55. doi: 10.1039/c0dt00382d. Epub 2010 Oct 4.
Magnetic coupling interactions of a Mn(III)(4) system are investigated by calculations based on density functional theory combined with a broken-symmetry approach (DFT-BS). Three different interactions including ferromagnetic and antiferromagnetic coupling are concomitant in this complex. This magnetic phenomenon of the complex is due to the different bridging angles between the Mn(III) centers in the three different models and the orbital complementarity of the μ-pzbg and μ-OCH(3) bridging ligands, which is proven by the analyses of the molecular orbitals. According to the analyses of the magneto-structural correlation, it is revealed that the magnetic coupling interaction switches from ferromagnetic to antiferromagnetic at the point of the bridging angle Mn-(μ-OCH(3))-Mn = 99°, which is equal to the value in the origin crystal. Significant correlation between the magnetic properties and the component of the d orbitals in these systems shows that the larger contribution of the d(z(2)) orbital corresponds to the larger ferromagnetic coupling interaction. These results should provide a means to control the magnetic coupling of the polynuclear Mn systems, which is instructive for the design of new molecular magnetic materials.
通过基于密度泛函理论结合破对称方法（DFT-BS）的计算，研究了 Mn(III)(4)体系的磁耦合相互作用。该配合物中存在三种不同的相互作用，包括铁磁和反铁磁耦合。这种配合物的磁现象是由于三个不同模型中 Mn(III)中心之间的不同桥接角度以及 μ-pzbg 和 μ-OCH(3)桥接配体的轨道互补性所致，这通过分子轨道的分析得到了证明。根据磁结构相关性的分析，揭示了磁耦合相互作用从铁磁到反铁磁的转变发生在桥接角 Mn-(μ-OCH(3))-Mn = 99°处，这与原始晶体中的值相等。这些体系中磁性质与 d 轨道分量之间存在显著的相关性，表明 d(z(2))轨道的贡献越大，铁磁耦合相互作用越大。这些结果为控制多核 Mn 体系的磁耦合提供了一种手段，对于设计新型分子磁材料具有指导意义。
