Seven cobalt(II) complexes of pyrazole derivatives and dinitrobenzoate ligands were synthesized and characterized. The single-crystal X-ray diffraction structure was determined for one of the ligands and one of the complexes. The analysis and spectral data showed that all the cobalt complexes had octahedral geometries, which was supported by DFT calculations. The complexes and their free ligands were evaluated against fungal strains of Candida albicans and emerging non-albicans species and epimastigotes of Trypanosoma cruzi. We obtained antifungal activity with a minimum inhibitory concentration (MIC) ranging from 31.3 to 250 µg mL⁻¹. The complexes were more active against C. krusei, showing MIC values between 31.25 and 62.5 µg mL⁻¹. In addition, some ligands (L1–L6) and complexes (5 and Co(OAc)₂ · 4H₂O) significantly reduced the yeast to hypha transition of C. albicans at 500 µg mL⁻¹ (inhibition ranging from 30 to 54%). Finally, the complexes and ligands did not present trypanocidal activity and were not toxic to Vero cells. Our results suggest that complexes of cobalt(II) with ligands derived from pyrazoles and dinitrobenzoate may be an attractive alternative for the treatment of diseases caused by fungi, especially because they target one of the most important virulence factors of C. albicans.

8-Formyl-7-hydroxycoumarin (A) and their derived salophen-type organocatalysts L1, L2, and L3 were used for the synthesis of cyclic carbonates from carbon dioxide (CO₂) and epoxides under solvent-, halide-, and metal-free conditions. According to previous optimization tests, L1 and L2 had the best catalytic activity presenting 89 and 92% conversion toward the synthesis of 3-chloropropylene carbonate (2c) using 8 bar CO₂, 100 °C at 9 h. Therefore, they were used as organocatalysts to complete the catalytic screening with 11 terminal epoxides (1a-k) exhibiting the highest TOF values of 20 and 22 h^-1 using 1c and 1b, respectively. Similarly, they were tested with an internal epoxide, such as cyclohexene oxide (1l) exhibiting 72% conversion, becoming the first salophen organocatalyst to obtain cis-cyclohexane carbonate (2l) in the absence of a cocatalyst. In addition, a reaction mechanism was proposed for the formation of cyclic carbonates based on experimental data and computational techniques; these contributed in establishing a probable role of CO₂ pressure along the catalysis and the hydrogen bonds that favor the stabilization of the different intermediates of the reaction.

Crystal growth of [Co(DNB) ₂ ] in different solvents is a thermodynamic process favored by Δ E _recrys (kcal mol ⁻¹ ) where mono/trinuclear molecules are obtained. Closeness of HOMO orbitals of solvents to the SOMOs orbitals of Co( ii ) ions guide the process.

Four Cu(II) complexes with coumarin‐derived ligands are synthesized and fully characterized, confirming a ratio of 1:1 ligand to metal. The complex C3 presents a geometry between a square pyramid and a trigonal bipyramid with a supramolecular arrangement ruled by hydrogen bonding. Photophysical studies show absorption and emission bands mainly by the contribution of the aromatic groups, mainly by the coumarin moiety. Furthermore, the Cu(II)/Cu(I) pair of these complexes is associated with irreversible redox reactions, according to electrochemical investigations. In addition, the complexes are tested against bacterial and fungi strains, with being C1 the most active complex with fungicidal activity and a good selectivity index. It is suggested that the mechanism of action of the complex is oxidative distress. The studies of the mechanism of action show that the possible antifungal activity of the complexes is by oxidative distress, which is also supported by electrochemical studies and changes in the membrane potential using a probe, JC‐1.