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Silver nanoparticles (AgNPs) at different amounts have successfully been deposited, by simple impregnation on the titanium dioxide (TiO 2) developed by the hydrothermal method. A textural and structural study of prepared materials was conducted using different analysis techniques, namely X-Ray Diffraction (XRD), Diffuse Reflectance UV-Vis (DR/UV-Vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, in addition to the Brunauer-Emmett-Teller (BET) method. The nanostructured prepared materials were tested for their antibacterial activity on four strains, i. e. two Gram-negative (GÀ) bacteria, namely Escherichia coli ATCC 8739 and A. baumanni ATCC 19606, and two Gram positive (G +) bacteria, i. e. S.aureus ATCC 6538 and E.cloacae ATCC 13047. The antioxidant effect was also tested on the reference radical DPPH°(2,2-diphenyl-1-picrylhydrazyle). AgNPs supported on TiO2 showed good antibacterial activity against the four selected strains. In addition, the minimum inhibitory concentration (MIC) was observed in the case of the low-grade silverdoped catalyst (0.1 % Ag/TiO2). Differently from the antibacterial activity, the antioxidant effect of the prepared materials was found to be pronounced in the cases of materials with high silver contents for which there was degradation of the radical in comparison with the one of the reference acid.

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Two novel thiosemicarbazones ligands have been synthesized and characterized by FT-IR, ESI-MS, 1 H NMR, and also by single-crystal X-ray diffraction for L1. The crystal structure shows that L1 molecules are planar and are connected via N-H-S and O-H-S interactions. The catecholase activity of is situ copper and cobalt complexes of this ligands has been investigated against 3,5-di-tert-butylcatechol. The progress of the oxidation reactions was closely monitored over time following the strong peak of 3,5-DTBC using UV-Vis. Oxidation rates were determined from the initial slope of absorbance vs. time plots, then analyzed by Michaelis-Menten equations. Catechol oxidation reactions were realized using different concentrations of copper and cobalt acetate and ligands (L/Cu: 1/1, 1/2, 2/1). The results show that all complexes were able to catalyze the oxidation of 3,5-DTBC. Acetate complexes have the highest activity. CuL1 and CoL1 complexes act as a catalyst and inhibitor. While copper and cobalt complexes obtained from ligand L2 illustrate concentration-independent oxidation activation. The hemolysis study performed by L1 increases as a function of its concentration. However, ligand L2 has no hemolytic effect.

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