Chen G, Espinosa-Perez G, Zentella-Dehesa A, Silaghi-Dumitrescu I, Lara-Ochoa F
Chemistry Department, Beijing Normal University, Beijing 100875, China.
Inorg Chem. 2000;39(16):3440-8. doi: 10.1021/ic990676z.
On the basis of the data obtained by X-ray diffraction, the properties of two independent crystallographic subsystems in the Fe(tpen)2.2/3H2O complex are studied in detail with the density functional method B3LYP. The energies of singlet, triplet, and quintet states at different temperatures are obtained, the influences of geometry on energy changes are analyzed, the regularity of the spin-state interconversions is investigated, and the effect of the triplet and action of the anion on spin crossover are discussed. This investigation demonstrates that (1) the energy difference between the high-spin state and singlet state decreases as the Fe-N distance and geometric distortion increase, (2) the spin-equilibrium system is predominantly in low-spin form below room temperature and the proportion of high-spin state rapidly increases above room temperature, (3) one of the two cation sites has a greater presence of the high-spin content, (4) the triplet state may be responsible for the fast rate of spin-state interconversions, and (5) the B3LYP method proves to be very adequate to study the spin-state transition of this complex.
基于X射线衍射获得的数据，采用密度泛函方法B3LYP详细研究了Fe(tpen)2.2/3H2O配合物中两个独立晶体学子系统的性质。获得了不同温度下单重态、三重态和五重态的能量，分析了几何结构对能量变化的影响，研究了自旋态相互转换的规律，并讨论了三重态和阴离子对自旋交叉的作用。该研究表明：(1) 随着Fe-N距离和几何畸变的增加，高自旋态与单重态之间的能量差减小；(2) 自旋平衡体系在室温以下主要以低自旋形式存在，在室温以上高自旋态的比例迅速增加；(3) 两个阳离子位点之一具有较高的高自旋含量；(4) 三重态可能是自旋态快速相互转换的原因；(5) B3LYP方法被证明非常适合研究该配合物的自旋态转变。
