Binuclear spin-crossover [Fe(bt)(NCS)2]2(bpm) complex: A study using first principles calculations

The spin-crossover [Fe(bt)(NCS)(2)](2)(bpm) complex is studied using spin-polarized density functional theory within the generalized gradient approximation, the Hubbard U and the weak van der Waals interactions in conjunction with the projector augmented wave method in its molecular and periodic arrangements. It is shown that the considered complex has three magnetic configurations [high spin state (HS)-HS, HS-low spin state (LS), and LS-LS] corresponding to those observed experimentally after two transition temperatures T-c((1)) of 163 K and T(c)((2) )of 197 K. For the HS-HS magnetic state, we found that the two Fe centers are antiferromagnetically coupled for both molecular and periodic structures in good agreement with the experimental observations. Our results show that the computed total energy difference between the magnetic state configurations of the considered Fe-2 complex is significantly smaller compared to those reported in the literature for other mono- or binuclear compounds.

Automated summary

The spin-crossover [Fe(bt)(NCS)(2)](2)(bpm) complex was studied using spin-polarized density functional theory, including the generalized gradient approximation, the Hubbard U, and weak van der Waals interactions. It was found that the complex exhibits three magnetic configurations (high spin state (HS)-HS, HS-low spin state (LS), and LS-LS) as observed experimentally at transition temperatures T-c((1)) = 163 K and T(c)((2)) = 197 K. The antiferromagnetic coupling between the two Fe centers in the HS-HS magnetic state was observed in both molecular and periodic structures, in good agreement with experimental observations. Additionally, the computed total energy difference between magnetic state configurations in the Fe-2 complex was significantly smaller compared to similar compounds in the literature.