ABSTRACT
In this study, 4-phenylthiazol-2-yl-(phenylhydrazono) acetonitrile (PTPA) azo dye was synthesized and studied from optical and electrical point of view. The tautomerization phenomenon of the PTPA dye was clarified using one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (1HNMR and 13C NMR), absorbance (UV-Vis), emission, and Fourier transform infrared spectroscopy (FT-IR). X-ray diffraction (XRD) evaluations were indicated that PTPA in powder and thin films crystallizes in a monoclinic system structure with nonstructural characteristics. Spectrophotometric measurements of absorbance A (λ), transmittance T (λ) and reflectance R (λ) at normal incidence light in the wavelength range 200-2500 nm were used to determine the optical band gap, extinction coefficient, k and refractive index, n. Also, non-linear optical parameters such as the third order non-linear susceptibility, χ(3) and nonlinear refractive index, n(2) of PTPA have revealed an awe-inspiring switching behavior, implying the possibility of using PTPA in optical switching systems. Finally, the electrical conductivity of the PTPA was shown to increase with rising temperature, indicating that it is a typical organic semiconductor. Mott's parameters were determined and discussed at low temperatures. Thus, PTPA is a promising organic semiconductor with broad utility potential in organic electronics such as organic light-emitting diodes (OLEDs).
ABSTRACT
A simple electrochemical sensor for nicotine (NIC) detection was performed. The sensor based on a glassy carbon electrode (GCE) was modified by (1,2-naphthoquinone-4-sulphonic acid)(Nq) decorated by graphene oxide (GO) nanocomposite. The synthesized (GO) nanosheets were characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), FT-IR, and UV-Visible Spectroscopy. The insertion of Nq with GO nanosheets on the surface of GCE displayed high electrocatalytic activity towards NIC compared to the bare GCE. NIC determination was performed under the optimum conditions using 0.10 M of Na2SO4 as a supporting electrolyte with pH 8.0 at a scan rate of 100 mV/s using both cyclic voltammetry (CV) and differential pulse voltammetry (DPV). This electrochemical sensor showed an excellent result for NIC detection. The oxidation peak current increased linearly with a 6.5-245 µM of NIC with R2 = 0.9999. The limit of detection was 12.7 nM. The fabricated electrode provided satisfactory stability, reproducibility, and selectivity for NIC oxidation. The reliable GO/Nq/GCE sensor was successfully applied for detecting NIC in the tobacco product and a urine sample.
ABSTRACT
The strategic idea in this work was to increase pH values by employing natural alkali sources (i.e., HCO3- and CO32-) from four tested agro-ashes as an alternative to chemicals (i.e., lime or soda ash). The considerable proportion of carbonates and bicarbonates in the investigated ash products had remarkable features, making them viable resources. All ash materials showed a significant ability for Ca ion elimination at high initial Ca ion concentrations. A slight quantity of ash (10 g/L) was sufficient for usage on very hard water contents up to 3000 ppm. Finally, the tested agro-ash was free of cost. Furthermore, unlike other conventional precipitants, such as NaOH, Ca(OH)2, NaHCO3, Na2CO3, and CaO, they are cost effective and ecologically sustainable. There is no need to employ any additional chemicals or modify the agro-ash materials throughout the treatment process. The benefits of the manufactured ash were assessed using a SWOT analysis.
ABSTRACT
Three novel potentially site-activated multitarget tacrine-(hydroxybenzoyl-pyridone) (TAC-HBP) hybrids were designed, synthesized and evaluated as acetylcholinesterase (AChE) inhibitors, antioxidants and biometal chelators. All of them are dual-binding site AChE inhibitors with activity in sub-micromolar range (IC50=0.57-0.78µM), which is comparable to the parent tacrine, and have good 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity (EC50=204-249µM) conferred by the hydroxybenzoyl-pyridone (HBP) moiety. Their chelating capacity towards redox-active and/or amyloid-ß-binding metal ions (Fe(III), Cu(II)), Zn(II)) was evaluated by using 2'-hydroxy-4'-methoxybenzoyl-2-pyridone derivative as a model compound in 30% w/w DMSO/water medium. It was proved that the HBP moiety acts as a moderate/good chelator of these biometals (pFe=13.9, pCu=6.0 and pZn=6.0 at pH6.0, CL/CM=10, CM=10-6M), being able to form complexes with ß-phenol-keto coordination mode, and that this chelating ability is preserved in the TAC-HBP hybrids.
