Synthesis and Characterization of Two Isostructural POCOP Ni(II) Pincer Complexes Containing Fluorothiophenolate Ligands: [Ni(SC6F4-4-H){C6H2-3-(C2H3O)-2,6-(OPiPr2)2}] and [Ni(SC6F5){C6H2-3-(C2H3O)-2,6-(OPiPr2)2}]

Among their many applications, metal pincer complexes are of interest for their properties as catalysts in cross-coupling reactions. Pincer ligands exhibit tridentate coordination to the metal center and occupy the meridional positions forming two chelate rings. The two Ni(II) POCOP pincer complexes with a fluorothiophenolate ligand reported herein, with formulas [Ni(SC6F4-4-H){C6H2-3-(C2H3O)-2,6-(OPiPr2)2}] (2) and [Ni(SC6F5){C6H2-3-(C2H3O)-2,6-(OPiPr2)2}] (3), are isostructural. Additionally, they are prepared in a facile manner from the chloride compound [NiCl{C6H2-3-(C2H3O)-2-6-(OPiPr2)2}] (1). The complexes exhibited slightly distorted square planar geometries around the metal. The fluorothiophenolate ligands are responsible of the C—H···F, C—F···π and C=O···πF interactions that contribute to stabilize the crystal structure arrays

Palladium Nanoparticles Functionalized with PVP-Quercetin Inhibits Cell Proliferation and Activates Apoptosis in Colorectal Cancer Cells

Nanotechnology is focused on the development and application of novel nanomaterials with particular physicochemical properties. Palladium nanoparticles (PdNPs) have been used as antimicrobials, antifungals, and photochemicals and for catalytic activity in dye reduction. In the present investigation, we developed and characterized PdNPs as a carrier of quercetin and initiated a study of its effects in colorectal cancer cells. PdNPs were first functionalized with polyvinylpyrrolidone (PVP) and then coupled to quercetin (PdNPs-PVP-Q). Our results showed that quercetin was efficiently incorporated to PdNPs-PVP, as demonstrated using UV/Vis and FT-IR spectroscopy. Using transmission electron microscopy, we demonstrated a reduction in size from 3–14.47 nm of PdNPs alone to 1.8–7.4 nm of PdNPs-PVP and to 2.12–3.14 of PdNPs-PVP-Q, indicating an increase in superficial area in functionalized PdNPs-Q. Moreover, hydrodynamic size studies using dynamic light scattering showed a reduction in size from 2120.33 nm ± 112.53 with PdNPs alone to 129.96 nm ± 6.23 for PdNPs-PVP-Q, suggesting a major reactivity when quercetin is coupled to nanoparticles. X-ray diffraction assays show that the addition of PVP or quercetin to PdNPs does not influence the crystallinity state. Catalytic activity assays of PdNPs-PVP-Q evidenced the chemical reduction of 4-nitrophenol, methyl orange, and methyl blue, thus confirming an electron acceptor capacity of nanoparticles. Finally, biological activity studies using MTT assays showed a significant inhibition (p < 0.05) of cell proliferation of HCT-15 colorectal cancer cells exposed to PdNPs-PVP-Q in comparison to untreated cells. Moreover, treatment with PdNPs-PVP-Q resulted in the apoptosis activation of HCT-15 cells. In conclusion, here we show for the first time the development of PdNPs-PVP-Q and evidence its biological activities through the inhibition of cell proliferation and apoptosis activation in colorectal cancer cells in vitro