M. Zubair

Tuning the band gap of TiO 2 by tungsten doping for efficient UV and visible photodegradation of Congo red dye

Tungsten-doped TiO2 (W@TiO2) nanoparticles, with different percentages of atomic tungsten dopant levels (range of 0 to 6 mol%) have been synthesized by the sol-gel method and characterized by UV-Visible spectroscopy, XRD, SEM, EDX, ICP-OES and XPS analysis. By means of UV-Vis spectroscopy, it has been observed that with 6 mol% tungsten doping the wavelength range of excitation of TiO2 has extended to the visible portion of spectrum. Therefore, we evaluated the photocatalytic activity of W@TiO2 catalysts for the degradation of Congo red dye under varying experimental parameters such as dopant concentration, catalyst dosage, dye concentrations and pH. Moreover, 6 mol% W@TiO2 catalyst was deposited on a glass substrate to form thin film using spin coating technique in order to make the photocatalyst effortlessly reusable with approximately same efficiency. The results compared with standard titania, Degussa P25 both in UV- and visible light, suggest that 6 mol% W@TiO2 can be a cost-effective choice for visible light induced photocatalytic degradation of Congo red dye.

Synthesis, spectroscopic characterization, and biological screening of levofloxacin based organotin(IV) derivatives

Four new organotin (IV) complexes with general formula R3SnL/R2SnL2, where R = CH3, n-C4H9, C6H5 and L = Levofloxacin, were synthesized and characterized by elemental analyses, FT-IR and NMR (1H and 13C) spectroscopy. Spectroscopic data suggested a six-coordinated geometry for diorganotin(IV) derivatives and a five-coordinated geometry for triorganotin(IV) derivatives. The value of Me–Sn–Me bond angle for di- and trimethyltin complexes using the Lockhart equation, were 150° and 116°, respectively, that corresponded to six and five-coordinate geometry, accordingly. The ligand and its complexes were screened for their antibacterial, antifungal, cytotoxic, and free radical scavenging (DPPH) antioxidant activities. The biological data indicated those as potentially bioactive in each field of the study. Accumulated data of DNA interaction with the synthesized complexes based on UV-Vis, cyclic voltammetry and viscometry suggested an intercalative mode of the interaction.