RESUMEN
Flavin-like ligands (L-1 and L-2) with extended π-conjugation were synthesized using microwave-assisted techniques. An N,N-chelating fragment was integrated into alloxazine units, providing binding sites for metal ions while retaining redox activity. The complexation capability of L-1 and L-2 with two prototypical Ru-scaffolds was examined to design Ru(II) complexes (M-1 and M-2), whose electronic properties were studied and compared with their corresponding ligands via absorption and emission spectroscopy, computational analysis (density functional theory (DFT) and time-dependent DFT (TD-DFT)), and cyclic voltammetry (CV). The ability of L-1 and M-1 to undergo alloxazine/isoalloxazine tautomerization was demonstrated to play a crucial role in the photocatalytic oxidation of NADH, including under green and red wavelengths. Moreover, the interaction of M-1 and M-2 with B-DNA and G-quadruplex structures was investigated. M-2 showed high stabilization of Kit1 and h-Telo oligonucleotides. Meanwhile, M-1 demonstrated switchable emissive properties with B-DNA and induced conformational changes in the h-Telo G-quadruplex structure.
RESUMEN
In this contribution we report the synthesis, characterization and in vitro anticancer activity of novel cyclometalated 4-phenylthiazole-derived ruthenium(II) (2a-e) and osmium(II) (3a-e) complexes. Formation and sufficient purity of the complexes were unambigiously confirmed by 1H-, 13C- and 2D-NMR techniques, X-ray diffractometry, HRMS and elemental analysis. The binding preferences of these cyclometalates to selected amino acids and to DNA models including G-quadruplex structures were analyzed. Additionally, their stability and behaviour in aqueous solutions was determined by UV-Vis spectroscopy. Their cellular accumulation, their ability of inducing apoptosis, as well as their interference in the cell cycle were studied in SW480 colon cancer cells. The anticancer potencies were investigated in three human cancer cell lines and revealed IC50 values in the low micromolar range, in contrast to the biologically inactive ligands.
