卷 50, 编号 11 (2024)

Mononuclear nickel complexes [NiL¹(NCS)₂] ⋅ 2DMSO (I), [NiL¹(NCS)₂] ⋅ DMF (II), and [NiL²(NCS)₂] ⋅ 0,5CH₃OH ⋅ 1,5H₂O (III) with the distorted octahedral coordination node, where L¹ and L² are the tetradentate ligand systems derived from the products of the condensation of diacetyl with 2-hydrazinoquinoline and 2-hydrazino-4,6-dimethylpyrimidine, respectively, are synthesized. The structures of the compounds are determined by IR pectroscopy and XRD (CIF files ССDС nos. 2219793 (I), 2142035 (II), and 2219794 (III)). The quantum chemical modeling of the axial parameter of magnetic anisotropy in the zero field (D) is performed for the synthesized compounds in the framework of the SA-CASSCF+NEVPT2 method. The complexes are shown to be characterized by three-axis magnetic anisotropy close to the light magnetization plane with positive D. The axial parameter of magnetic anisotropy (D_exp = 8.79 cm^–1) determined by the approximation of the magnetometry data on complex [NiL²(NCS)₂] ⋅ 0,5CH₃OH ⋅ 1,5H₂O is consistent with the calculated value (D_calc = 11.5 cm^–1).

New coordination compounds of copper(I), copper(II), cobalt(II), and nickel(II) with 2,4-dimethylpyrazolo[1,5-а]benzimidazole (L) were synthesized and studied. The complexes [CuLCl] (I), [CuLBr] (II), [CuL₂Cl₂] (III), [CuL₂(NO₃)₂] · H₂O (IV), [CoL₂Cl₂] · 0,5H₂O (V), [CoL₂(NO₃)₂] · · 0,5H₂O (VI), and [NiL₂(NO₃)₂] · 0,5H₂O (VII) were studied by IR spectroscopy and powder and single crystal X-ray diffraction (CCDC nos. 2321779 ([CuL₂Cl₂]), 2321780 ([CoL₂(NO₃)₂])). The results indicate that the coordination polyhedron in 2,4-dimethylpyrazolo[1,5-a]benzimidazole complexes is formed by the nitrogen atoms of the monodentate ligand and the coordinated anion. The cytotoxic and cytostatic properties of L and complexes I–III were studied in relation to the HepG2 hepatocellular carcinoma cells.

The molecular structures and relative energies of trans- and cis-isomers of bis(chelate) complexes of Pd(II) and Pt(II) salicylal-, thiosalicylal-, and selenosalicylaldiiminates are calculated using the density functional theory. The role of the kinetic factor in the formation of the trans- and cis-isomers of the PdL₂ and PtL₂ complexes is studied in the framework of the model of the step-by-step formation of the bis(ligand) metal complexes ML₂ (M⁺⁺ + (L)^– → (ML)⁺, (ML)⁺ + (L)^–→ ML₂). The competition of the trans- and cis-isomers of the PdL₂ and PtL₂ bis(chelate) azomethine complexes with the coordination nodes MN₂O₂, MN₂S₂, and MN₂Se₂ is shown to be determined by both the energy preference of one of possible configurations and activation barriers of the isomerization of the products formed in the first step of the interaction of the initial reagents.