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This work is focused on the preparation and characterization of a series of cobalt complexes with Schiff base ligands that tend to adopt the shape of a trigonal prism. These complexes were synthesized, structurally characterized, and subsequently subjected to magnetic measurements using magnetometry and EPR spectroscopy. It was found that the complexes exhibit single-molecule magnet properties in the presence of a magnetic field. One of the complexes was magnetically diluted, revealing single-molecule magnet properties even in a zero field. These properties were further investigated through theoretical calculations.

In this work, we were dealing with the preparation of cobalt(II) complexes with 17-membered pyridine-piperazine macrocyclic ligand with atypical shape of trigonal prism coordination polyhedron. The ligand is coordinated by all five N-donor atoms and the last position is occupied by monovalent coligand – halide or pseudohalide. A negative value of the D-parameter describing the magnetic anisotropy in the range -20 to -41 cm^-1 was found for all complexes and the magnetic behaviour was investigated using theoretical calculations and magnetochemical measurements. Five field-induced single-molecule magnets were prepared and the magnetostructural correlations were investigated.

In this review article, we focused on a comprehensive overview of the structural types of multi-targeted Pt(IV) complexes, and they were categorized according to various criteria - a parent Pt(II) complex, a number and type of bioactive ligands, a type of second (innocent) axial ligand, and nuclearity. For the first time, we also reviewed multi-targeted Pt(II) complexes releasing cytotoxic Pt(II) species and bioactive ligand(s) as well, which also allowed a critical comparison of the two structural types. Special attention is paid to the discussion of the solution behaviour, activation and biological activity of the reviewed types of Pt complexes. Relevant comparison of these crucial features should be beneficial for future development of these pharmacologically highly perspective compounds.

The work is based on theoretical calculations focused on the magnetic properties of a series of dysprosocenium-type complexes. For these complexes, structure optimizations were performed, an analysis of their vibrational frequencies was conducted, and subsequently, their energy barriers U_eff were studied using methods based on CASSCF calculations. Furthermore, spin-phonon coupling was investigated, where a new method based on comparing the influence of molecular vibrations on the energy barrier was developed and compared to the already used method, which relies on crystal field parameters. The study of these substances revealed interesting structural correlations that could potentially be utilized in the design of single-molecule magnets with high blocking temperatures.

Half-sandwich Ru(II) and Ir(III) complexes with a thiadiazole-based ligand L1 (2-(furan-2-yl)-5-(pyridin-2-yl)-1,3, 4-thiadiazole) were synthesized and characterized by different analytical methods. The structures of the molecules were analysed and interpreted by computational methods (DFT and QT-AIM). The complexes showed the ability to oxidize NADH to NAD⁺, with the Ir(III) complexes exhibiting higher catalytic activity compared to their Ru(II) analogues. The results of in vitro testing of antiproliferative activity showed that Ir(III) complexes had no effect on healthy human fibroblasts, demonstrating their selectivity. In contrast, the complexes showed inhibitory effects on the metabolic and proliferative activity of cancer cells.