The preparation of a new type of ferrocene-based compounds with large conjugated system containing symmetrical aromatic vinyl with Schiff base moieties and the study of their third-order nonlinear optical properties

Synthesis, physicochemical studies, fluorescence behavior, and anticancer properties of transition metal complexes with the pyridyl ligand

A novel series of complexes with the formula [MLCl] [M = Co(II) (1), Ni(II) (2), Cu(II) (3), Zn(II) (4)] arising from Pyridyl ligand, N,N’-bis(1-(2-pyridyl)ethylidene)-2,2-dimethylpropane-1,3-diamine), ligand, L, was synthesized and investigated by elemental analyses, FT-IR, 1H and 13C NMR, Powder XRD, and thermal analyses. TGA analysis indicated that all complexes degraded in three different steps, while the PXRD examination showed well-defined sharp crystalline peaks for the complexes, indicating significant crystallinity. The antiproliferative activity of the ligand and its complexes were also evaluated in vitro against the HeLa (Human Cervical Cancer Cells) and HCT116 (Colon Cancer Cells) cell lines. The findings suggested complex 4 to be potential anticancer agent against these cell lines. In addition, ligand and its complexes also exhibited considerable emission properties.

Two New Fluorinated Phenol Derivatives Pyridine Schiff Bases: Synthesis, Spectral, Theoretical Characterization, Inclusion in Epichlorohydrin-β-Cyclodextrin Polymer, and Antifungal Effect

It has been reported that the structure of the Schiff bases is fundamental for their function in biomedical applications. Pyridine Schiff bases are characterized by the presence of a pyridine and a phenolic ring, connected by an azomethine group. In this case, the nitrogen present in the pyridine is responsible for antifungal effects, where the phenolic ring may be also participating in this bioactivity. In this study, we synthesized two new pyridine Schiff Bases: (E)-2-[(3-Amino-pyridin-4-ylimino)-methyl]-4,6-difluoro-phenol (F1) and (E)- 2-[(3-Amino-pyridin-4-ylimino)-methyl]-6-fluoro-phenol (F2), which only differ in the fluorine substitutions in the phenolic ring. We fully characterized both F1 and F2 by FTIR, UV-vis, ¹H; ¹³C; ¹⁹F-NMR, DEPT, HHCOSY, TOCSY, and cyclic voltammetry, as well as by computational studies (DFT), and NBO analysis. In addition, we assessed the antifungal activity of both F1 (two fluorine substitution at positions 4 and 6 in the phenolic ring) and F2 (one fluorine substitution at position 6 in the phenolic ring) against yeasts. We found that only F1 exerted a clear antifungal activity, showing that, for these kind of Schiff bases, the phenolic ring substitutions can modulate biological properties. In addition, we included F1 and F2 into in epichlorohydrin-β-cyclodextrin polymer (βCD), where the Schiff bases remained inside the βCD as determined by the k_i, TGA, DSC, and S_BET. We found that the inclusion in βCD improved the solubility in aqueous media and the antifungal activity of both F1 and F2, revealing antimicrobial effects normally hidden by the presence of common solvents (e.g., DMSO) with some cellular inhibitory activity. The study of structural prerequisites for antimicrobial activity, and the inclusion in polymers to improve solubility, is important for the design of new drugs.