The geometrical and electronic structures of iron and cobalt metal complexes of porphyrazine and tetra(1,2,5-thiadiazole)porphyrazine in ground and low-lying excited electronic states were determined by DFT calculations and the complete active space (CASSCF) method with following accounting dynamic correlation by multiconfigurational quasidegenerate second-order perturbation theory (MCQDPT2). A geometrical structure of D4h symmetry has been obtained for all four complexes. According to data obtained by the MCQDPT2 method, the complexes of cobalt and iron possess the ground states ²A1g and ³A2g, respectively, and wave functions of the ground states have the form of a single determinant. It is shown that the crystal field theory (CFT) can be used to describe the sequence of electronic states of the investigated complexes. The nature of the bonds between metal atoms and nitrogen atoms has been described using the analysis of the electron density distribution in the frame of Bader’s quantum theory of atoms in molecule (QTAIM).

中文翻译：

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四(1,2,5-噻二唑)四氮杂卟啉铁钴金属配合物的电子结构和化学键合特性

通过DFT计算和完全活性空间（CASSCF）方法确定了四（1,2,5-噻二唑）四氮杂卟啉铁钴金属配合物在地面和低激发电子态的几何和电子结构通过多构型准生成二阶微扰理论（MCQDPT2）计算动态相关性。D的几何结构4H已获得所有四个配合物的对称性。根据MCQDPT2方法获得的数据，钴和铁的配合物具有基态² A1G和³ A2G, 和基态的波函数具有单个行列式的形式。结果表明，晶体场理论（CFT）可用于描述所研究配合物的电子态序列。金属原子和氮原子之间的键的性质已经使用巴德分子中原子量子理论 (QTAIM) 框架中的电子密度分布分析进行了描述。