Synthesis and Antibacterial Activity of 1,3,4-Oxadiazole and 1,2,4-Triazole Derivatives of Salicylic Acid and its Synthetic Intermediates

Eight compounds 2–9 have been synthesized starting from salicylic acid, two of them (7 and 9) are novel. The four final products namely: 5-(2-hydroxy phenyl)-1,3,4-oxadiazole-2-thione 4, 3-(2-hydroxy phenyl)-1H-1,2,4-triazole-5-thiol 6, 3-(2-hydroxy phenyl)-4-amino-1,2,4-triazole-5-thiol 8 and 3-(2-hydroxy phenyl)-1-amino-1,2,4-triazole-5-thiol 9 have been prepared using known reactions. The structures of intermediates and final products were determined by spectroscopic IR, UV, 1H-NMR & MS-methods in addition to elemental analysis. Antibacterial activities of compounds 1–6 and 8 were investigated in vitro against Escherichia coli,  Staphylococcus aureus and Pseudomonas aeruginosa and the results are reported herein.KEYWORDS: 1,3,4-Oxadiazole-2-thione; 1H-1,2,4-triazole-5-thiol; 4-amino-1,2,4-triazole-5-thiol; salicylic acid; antibacterial activity

Photoluminescence Study of Eu+3 doped ZnO Nanocolumns Prepared by Electrodeposition Method

[EN] Europium doped ZnO (ZnO:Eu) nanocolumns were grown on indium tin oxide substrates (ITO) by electrodeposition method in zinc nitrate aqueous solution with different concentration of Eu. According to XRD results electrodeposited ZnO:Eu films exhibit thigh crystalline quality with a preferential orientation parallel to c-axis. Moreover, the (002) peak position shifts toward to lower angles confirming the incorporation of Eu+3 ions into the ZnO lattice. The crystallite size of a pure ZnO decreases when increasing the Eu doping. SEM images reveal a well dense nanocolumns arrays perpendicular to the surface. Furthermore, doping with Eu+3 ions leads to a change in the top of nanocolumns from hexagonal to conic-hexagonal shape. The average diameters of nanocolumns are found to be around 200 nm and 180 nm for undoped ZnO and Eu doped ZnO, respectively. Photoluminescence (PL) emission from ZnO:Eu thin films reveals the typical peaks related to excitons and intrinsic defects in ZnO and four narrow peaks in the red region attributed to 4f-shell transition in Eu+3 ions. As Eu doping increased, PL peaks related to Eu+3 emission showed an increase in intensity and a shift in its wavelength position. A schematic drawing of the excitation mechanism and related emission process is proposed.Nouri, AN.; Beniaiche, AB.; Marí, B.; Guessas, H.; Azizi, A. (2017). Photoluminescence Study of Eu+3 doped ZnO Nanocolumns Prepared by Electrodeposition Method. Optik - International Journal for Light and Electron Optics. 139:104-110. doi:10.1016/j.ijleo.2017.03.075S10411013