مدرس عبير محمد جبار

Efficient organic nonlinear optical (NLO) material is of great interest for photonic and optoelectronic applications. The present work involved the doping of Phenazopyridine extracted from expired pharmaceutical tablets into poly(methyl methacrylate) (PMMA) to synthesize composite thin films of PMMA doped with 10, 30 and 50 wt% Phenazopyridine. FTIR, UV–Vis, 1H NMR and 13C NMR spectroscopy were used to confirm the chemical structure of the extracted compound. The electronic structure and optical properties were studied with the help of the density functional theory (DFT) and time dependent density functional theory (TD-DFT) methods at B3LYP/6–311 + G(d,p) and CAM-B3LYP/6–311 + G(d,p) levels of theory. The molecular orbitals calculated showed an efficient intramolecular charge-transfer character of Phenazopyridine with its donor–π–acceptor architecture. Open and closed aperture Z-scan methods were used to measure the nonlinear optical properties using continuous wave laser excitation at 532 nm. The composite films showed significant saturable absorption and saturable absorption index in the reverse direction, as well as negative nonlinear refraction, which showed self-defocusing properties. The nonlinear optical response was found to be higher at higher dye concentration, while the 50 wt% Phenazopyridine/PMMA film showed the highest nonlinear absorption coefficient and optical limiting performance. The nonlinear behavior observed is explained by the excited-state absorption and thermally induced nonlinear effects. The results indicate that Phenazopyridine/PMMA composites have interesting nonlinear optical properties and show that the use of outdated pharmaceutical drugs as functional materials in photonic applications seems promising.

This study prepared the azo compound (A) and the Schiff base compound (S) from the same amine compound 3-aminopyridine. The identity of these two prepared compounds was confirmed using several techniques: via FT-IR, UV-vis, 1H NMR, 13C NMR, EI-Mass, SEM, and EDS spectroscopic techniques. These two compounds were applied as corrosion inhibitors for carbon steel N80 by taking several molar concentrations: 0.0001; 0.0005; 0.001 and 0.005 M, at different temperatures of 298, 308 and 318 K in an acidic medium of HCl at a concentration of one molar. The technique used in this study is electrochemical polarization (Tafel curves). The results obtained from this study confirmed that the corrosion current is high in the absence of inhibitors but decreases in the presence of inhibitors. Also, the corrosion current is inversely proportional to the increase in concentrations of organic inhibitors and directly proportional to the temperature increase. Besides, the percentage of inhibition efficiency increases with increasing temperature, indicating that the adsorption is chemisorption. We also studied the activation energy, and the following thermodynamic parameters have been calculated from the Langmuir adsorption isotherm: free energy (ΔG0), enthalpy (ΔH0) and entropy change (ΔS0). This electrochemical method (Tafel extrapolation) and SEM and EDS techniques have confirmed that these prepared inhibitors are effective against corrosion through the formation of a protective film on the surface of carbon steel.

A new heterocyclic organic corrosion inhibitor, the Schiff base [N-(benzo[d]thiazol-2-yl)-1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)methanimine], has been prepared by reflux distillation. Its properties have been analyzed by means of FT-IR, UV-Vis, 1H NMR, 13C NMR, EI-Mass, SEM and EDS spectroscopic techniques. This synthesized chemical was used as a corrosion inhibitor in our study at various concentrations (0.0001, 0.0005, 0.001, and 0.005 M) and temperatures (298, 308, and 318 K) on carbon steel N80 in 1 M HCl and was studied by potentiodynamic polarization methods (Tafel plots). The findings proved that with an increase in concentration and temperature of the inhibitor, the percentage of inhibition efficiency (%IE) elevates. The most excellent corrosion inhibition efficiency of 95.71% was reached at 0.005 M at 318 K in 1 M HCl. The results of Sh1 as a corrosion inhibitor indicated that the adsorption of the inhibitor on the surface of carbon steel was of physisorption type and obeyed the Langmuir adsorption isotherm. Accordingly, we also studied the activation energy, and thermodynamic parameters were calculated from the Langmuir adsorption isotherm, including the free energy ΔG0, enthalpy ΔH0, and entropy change ΔS0. This electrochemical method (Tafel extrapolation) along with SEM and EDS techniques confirmed that this prepared inhibitor protects carbon steel from corrosion by forming a film (protection layer) on its surface.

New heterocyclic azo compounds were prepared by coupling the diazonium salts with N-(4-methylphenyl)maleimide with various different sulfa compounds. The structure of heterocyclic azo compounds was determined by MS, FT-IR and 1H NMR techniques. The density function theory calculation at the B3LYP method with 6-311G(d,p) basis set is used to investigate the electronic structures of the prepared heterocyclic azo compounds. Mulliken charge distributions and HOMO-LUMO energies of the mentioned compounds have been also computed by same method and basis set.