A series of organoruthenium(II) chlorido complexes with fluorinated O,O-ligands [(η6-p-cymene)Ru(F3C-acac-Ar)Cl] (1a–6a) and their respective 1,3,5-triaza-7-phosphaadamantane (pta) derivatives [(η6-p-cymene)Ru(F3C-acac-Ar)pta]PF6 (1b–6b) were synthesized and fully characterized in both solution and solid state. All complexes were inactive against nonmalignant keratinocytes but displayed variable activity against cancer cell models (ovarian, osteosarcoma). Compounds with a ligand containing the 4-chlorophenyl substituent (6a and 6b) exhibited the strongest anticancer effects. Despite a marginally lower cellular Ru accumulation compared to the chlorido complexes, pta analogues showed higher activity especially in the osteosarcoma model. Reduction of glutathione levels by buthionine sulfoximine (BSO) significantly enhanced the activity of all compounds with the most pronounced effects being observed for the pta series resulting in IC50 values down to the nanomolar range. While all chlorido complexes potently induce reactive oxygen species, DNA damage, and apoptosis, the respective pta compounds widely lacked ROS production but blocked cell cycle progression in G0/G1 phase.
COBISS.SI-ID: 1536265667
Manganese(II) complexes with the quinolone antimicrobial agent sparfloxacin (Hsf) in the absence or presence of the nitrogen-donor heterocyclic ligands 1,10-phenanthroline (phen), 2,2′-bipyridine (bipy), 2,2′-bipyridylamine (bipyam) or pyridine (py) were synthesized and characterized with diverse physicochemical and spectroscopic techniques. The crystal structure of complex [Mn(sf)2(phen)]·4MeOH was determined by X-ray crystallography. In the resultant complexes, the deprotonated sparfloxacinato ligands are bidentately bound to manganese(II) through the pyridone oxygen and a carboxylato oxygen. The antimicrobial activity of the complexes was tested against four different microorganisms (Escherichia coli, Xanthomonas campestris, Staphylococcus aureus and Bacillus subtilis) and was found to be similar to or higher than free Hsf. The binding of the complexes to calf-thymus DNA (CT DNA) was monitored by UV spectroscopy and DNA viscosity measurements, which indicated intercalation as the most possible mode, and the DNA-binding constants of the complexes were calculated. The ability of the complexes to displace ethidium bromide (EB) from the EB–DNA complex was also investigated. Fluorescence emission spectroscopy was used to evaluate the interaction of the complexes with human or bovine serum albumin proteins revealing their binding with relatively high binding constant values.
COBISS.SI-ID: 1536169411
ZnO nanoparticles were synthesized solvothermally in various diols (ethylene glycol, di(ethylene glycol), tetra(ethylene glycol), 1,2-propanediol, 1,4-butanediol), using basic zinc carbonate (2ZnCO3·3Zn(OH)2) as a precursor for the first time. Since ZnCO3 was sparingly soluble in diols the transformation reaction proceeded at a low reaction rate. Ethylene glycol was found as the most suitable medium among five diols studied yielding the smallest ZnO particles (~55 nm) and short reaction time, tr (2 h). Diols with shorter chain length produced smaller ZnO particles. p-Toluene sulfonic acid (p-TSA) acted as a catalyst and reduced tr from 8 h to 2 h in concentration of 0.02 M. Optimum reaction conditions for the synthesis in ethylene glycol were 185 °C and 2 h. At higher p-TSA concentrations (0.04–0.08 M) the size of ZnO particles was reduced from 500–800 nm to 50–100 nm and crystallite size to 25–30 nm. Benzene sulfonic acid (BSA) and inorganic bases (LiOH, NaOH, and KOH) also showed catalytic activities. Raman and photoluminescence spectroscopies revealed high concentration of defects on ZnO surface causing the emission of visible light and giving this type of ZnO higher potential in various (opto)-electronic application in comparison to Zn(II) acetate based ZnO.
COBISS.SI-ID: 5800730
Sub-solidus phase relations in the ternary CaO–La2O3–TiO2 system at 1400 °C in air were determined. The multi-phase samples were prepared by a solid-state reaction method, whereas the single-phase samples for the structure analysis of selected solid solutions were prepared by a wet-precipitation method in order to provide good homogeneity of the starting mixtures. The phases in the prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The oxides form seven ternary compounds in the equilibrium state, many solid solutions (which extend across a broad concentration region), and a large, single-phase area based on the CaTiO3 solid solution. The structures of several new phases – solid solutions on the tie lines CaTiO3–Ca3La4Ti3O15 and La2TiO5–Ca3La4Ti3O15 – were determined in detail.
COBISS.SI-ID: 1536308931
Three of the fundamental catalytic limitations that have plagued the electrochemical production of hydrogen for decades still remain: low efficiency, short lifetime of catalysts and a lack of low-cost materials. Here, we address these three challenges by establishing and exploring an intimate functional link between the reactivity and stability of crystalline (CoS2 and MoS2) and amorphous (CoSx and MoSx) hydrogen evolution catalysts. We propose that Co2+ and Mo4+ centres promote the initial discharge of water (alkaline solutions) or hydronium ions (acid solutions). We establish that although CoSx materials are more active than MoSx they are also less stable, suggesting that the active sites are defects formed after dissolution of Co and Mo cations. By combining the higher activity of CoSx building blocks with the higher stability of MoSx units into a compact and robust CoMoSx chalcogel structure, we are able to design a low-cost alternative to noble metal catalysts for efficient electrocatalytic production of hydrogen in both alkaline and acidic environments.
COBISS.SI-ID: 1536662979