Bishydrazone ligand and its Zn-complex: synthesis, characterization and estimation of scalability inhibition mitigation effectiveness for API 5L X70 carbon steel in 3.5% NaCl solutions.

Bishydrazone ligand, 2,2'-thiobis(N'-((E)-thiophen-2-ylmethylene) acetohydrazide), H2TTAH and its Zn- complex were prepared and characterized through elemental analysis and various spectroscopic performances as well as (IR, 1H and 13C NMR, mass and (UV-Vis) measurements. The synthesized complex exhibited the molecular formula [Zn2(H2TTAH)(OH)4(C5H5N)3C2H5OH] (Zn-H2TTAH). To assess their potential as anti-corrosion materials, the synthesized particles were assessed for their effectiveness for API 5L X70 C-steel corrosion in a 3.5% NaCl solution using electrochemical methods such as potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS). Additionally, X-ray photoelectron spectroscopy (XPS) was employed to examine the steel surface treated with the tested inhibitors, confirming the establishment of an adsorbed protecting layer. The results obtained from the PP plots indicated that both H2TTAH and Zn-H2TTAH act as mixed-type inhibitors. At a maximum concentration of 1 × 10-4 M, H2TTAH and Zn-H2TTAH exhibited inhibition efficiencies of 93.4% and 96.1%, respectively. The adsorption of these inhibitors on the steel surface followed the Langmuir adsorption isotherm, and it was determined to be chemisorption. DFT calculations were achieved to regulate the electron donation ability of H2TTAH and Zn-H2TTAH molecules. Additionally, Monte Carlo (MC) simulations were conducted to validate the adsorption configurations on the steel surface and gain insight into the corrosion inhibition mechanism facilitated by these molecules.

Simple dihydropyridine-based colorimetric chemosensors for heavy metal ion detection, biological evaluation, molecular docking, and ADMET profiling.

In this study, two novel chemosensors containing dihydropyridine fragment namely; (2E, 2E')-1,1'-(2,6-dimethyl-1,4-dihydropyridine-3,5-diyl)bis(3-(4-(dimethylamino)phenyl)prop-2-en-1-one) (1), (2E,2E',4E,4E')-1,1' -(2,6-dimethyl-1,4-dihydropyridine-3,5-diyl)bis(5-(4-(dimethylamino)phenyl)penta-2,4-dien-1-one) (2) have been synthesized and characterized. The solvatochromic behavior was explored in different solvents of various polarities. The visual detection, as well as UV-Vis and fluorescence measurements were carried out to explore the colorimetric and optical sensing properties of the investigated chemosensors towards various metal ions such as Al3+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Mg2+, Hg2+ and Zn2+. The chemosensors 1 and 2 have strong detecting abilities, with excellent sensitivity and selectivity for Cu2+ and Fe3+, respectively, over the other metal ions. The chemosensors were totally reversible upon addition of EDTA to the formed complexes and displayed a turn on-off-on fluorescence response based on an effect of chelation-quenching fluorescence. The antioxidant activities of the investigated chemosensors were assessed. They were examined in-silico for their capacity to block the Akt signaling pathway, which is involved in cancer proliferation with interpreting their pharmacokinetics aspects. Furthermore, in-vitro antitumor evaluation against a panel of cancer cell lines for the investigated chemosensors has been examined. Conclusively, chemosensor 1 was more effective at scavenging free radicals and as an anticancer agent and could be exploited as a therapeutic candidate for cancer therapy than chemosensor 2 due to its potential inhibition of Akt protein.

Tunable Anticorrosive Effects of Newly Synthesized Benzothiazole Azo Dyes by Potassium Iodide Synergism for Carbon Steel in 1 M HCl: Combined Experimental and Theoretical Studies.

Herein, we synthesized three novel benzothiazole azo dyes, including 4-chloro-2-(4-methyl-benzothiazol-2-ylazo)-phenol (CMBTAP), 1-(6-chloro-benzothiazol-2-ylazo)-naphthalen-2-ol (CBAN), and 2-(6-chloro-benzothiazol-2-ylazo)-4-methyl-phenol (CBAMP), and investigated their corrosion inhibition effect on carbon steel. The dyes were characterized by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance (NMR), 13C NMR, and mass spectroscopy. Weight loss, electrochemical impedance spectroscopy, and potentiodynamic polarization measurements were performed to investigate the corrosion inhibition effect of the dyes on carbon steel in a 1.0 M HCl solution. The synergistic effects of the dyes with potassium iodide (KI) were also investigated. The inhibition efficiency (IE%) was enhanced by increasing the dose of the dyes (1 × 10-5 to 2 × 10-4 M) and decreased as the temperature increased from 25 to 45 °C. The addition of KI to a 1.0 M HCl solution containing the dyes improved the performance and efficiency as iodide ions promoted the formation of inhibition films on the surface of carbon steel. The dyes are mixed-type inhibitors, according to Tafel polarization. Scanning electron microscopy and energy dispersive X-ray analysis were used to evaluate the surface morphology of carbon steel sheets. Quantum theory calculations were utilized to evaluate the relationship between the dyes' chemical structures and their inhibitory efficiency, which confirmed the experimental results. The calculations revealed that the dyes have low energy gap and Milliken and Fukui indices. Among all of the dyes, CMBTAP showed the highest adsorption energy. The corrosion IE was in the order CMBTAP > CBAMP > CBAN.

Facile synthesis of superparamagnetic Fe3O4@noble metal core-shell nanoparticles by thermal decomposition and hydrothermal methods: comparative study and catalytic applications.

Herein, we report on developing a facile synthetic route for reusable nanocatalysts based on a combination of the supermagnetic properties of magnetite with the unique optical and catalytic properties of noble metal hybrid nanomaterials. We compare two different synthetic methods, to find out which is best from synthetic and application points of view, for the synthesis of Fe3O4 and Fe3O4@M (M = Ag or Au) core-shell hybrid nanostructures. The two different single-step synthetic methods are: thermal decomposition and hydrothermal. The structural, morphological and magnetic properties of the obtained Fe3O4 and Fe3O4@M nanoparticles were characterized by various techniques. XRD of the Fe3O4 nanoparticles exhibited sharp and strong diffraction peaks, confirming the highly crystalline structure of the Fe3O4 particles synthesized by the hydrothermal method, while broad and weak peaks were observed on using the thermal decomposition method. Both Fe3O4@Ag and Fe3O4@Au core-shells obtained by the hydrothermal method showed the reflection planes of Fe3O4 and additional planes of Ag or Au. But on the formation of Fe3O4@Ag/Au by the thermal decomposition method the peak for Fe3O4 disappeared and only the diffraction peaks of Ag or Au appeared. According to TEM analysis there was a broad particle-size distribution, random near-spherical shapes and slight particle agglomeration for Fe3O4 synthesized by the thermal decomposition method. However, there was a moderate size distribution, spherical shapes and well-dispersed particles without large aggregations for the hydrothermal method. TEM images of the synthesized nanoparticles by the two methods used showed a pronounced difference in both size and morphological shape. The catalytic performance of the synthesized nanoparticles was examined for the reduction of Congo red dye in the presence of NaBH4. The Fe3O4 nanocatalyst maintained its catalytic activity for only one cycle. In the cases of Fe3O4@Au and Fe3O4@Ag, the catalytic activity was conserved for four and ten successive cycles, respectively. Based on the obtained results, it was concluded that the hydrothermal synthesis of Fe3O4, Fe3O4@Ag and Fe3O4@Au nanostructures is highly recommended due to their selectivity and merits.

Simple, selective detection and efficient removal of toxic lead and silver metal ions using Acid Red 94.

Toward the goal of detecting toxic elements and removing them from drinking water, we report herein the utilization of Acid Red 94 (AR94) in sensing the hazardous metal ions in water. Among the various examined metal ions (Ag+, Pb2+, K+, Mn2+, Zn2+, La3+, Hg2+, Ca2+, Cd2+, Co2+, and Ni2+), the UV-visible absorption spectra showed high selectivity and sensitivity for toxic silver and lead metal ions in an aqueous solution. The observed absorption spectral changes and the rapid color changes confirm complex formation between AR94 and both Ag+ and Pb2+ metal ions. The emission measurements showed the significant fluorescence quenching of the singlet excited state of AR94 in the presence of Ag+ and Pb2+ metal ions suggesting the formation of an irradiative dye-metal complex under the prevailing experimental conditions. In order to remove the accumulated complexes of AR94 with silver metal ions, safe and harmless mesoporous titanium dioxide was utilized efficiently in removing the complexes with adsorption capacities of 91% at 30 minutes. These findings suggest a simple, fast and efficient method for both detecting silver in water, and removing the formed AR94-metal complexes in water. In addition, AR94 is shown to be a good sensor for the presence of Ag and Pb nanoparticles, NPs, in aqueous solution. The absorption and emission spectra of AR94 showed significant changes that may be rationalized by the strong electromagnetic coupling induced by NPs plasmonic effects. These findings render AR94 a sensitive and selective sensor and a visual indicator for the qualitative and quantitative detection of silver ions, lead ions and their nanoparticles.

Immobilization of horseradish peroxidase into cubic mesoporous silicate, SBA-16 with high activity and enhanced stability.

Mesoporous silicate, SBA-16 is one of the most promising supports for horseradish peroxidase. In this study, SBA-16 was synthesized, and the anchored HRP enzyme in the organized porous networks, SBA-16. The mesoporous material, SBA-16 and the anchored HRP enzyme were characterized by Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption isotherms, low-angle XRD and thermogravimetric analysis. The percentage of immobilized HRP was 57%. The enzyme affinity constant, Km values of soluble and immobilized enzyme were 5.27 and 3.9 mM for hydrogen peroxide and 12 and 10.4 mM for guiacol, respectively, indicating that the immobilized enzyme had more affinity to the substrate than free HRP. Also, the free and immobilized enzyme had pH and temperature optima at 5.6, and 40 °C, respectively. The free enzyme was stable at 40 °C but that for the immobilized enzyme was detected up to 60 °C. Reusability of immobilized enzyme was found to be 10 cycles; the immobilized enzyme can only retain 50% of its activity after 5 cycles. The results indicate the higher efficiency, stability, and reusability of the immobilized enzyme than free enzyme. The HRP immobilized to SBA-16 due to the large surface area, and narrow pore size distribution of SBA-16.

The effect of ring size on the optical behavior of novel photochromic push-pull dyes.

The photophysical behaviors of newly synthesized photochromic dyes have been investigated in different solvents of various polarities using steady-state absorption and emission techniques. It was found that, the absorption and emission spectra of these dyes depend on the ring size and the solvent polarity. The higher values of the dipole moments of the investigated dyes in the excited state than those in the ground state suggest that these dyes can serve as good candidate components of nonlinear optical materials. Additionally, the photoisomerization parameters (percentage of composition of cis isomers and quantum yields of photoisomerization) depend on the polarity and the viscosity of the used solvents as well as the ring size. The molecular motion that occurs in the isomerization process has facilitated the development of molecular devices. Finally, the halochromic behaviors of the investigated dyes promise them to act as acid-base indicators.

Fluorescence characteristics and inclusion of ICT fluorescent probe in organized assemblies.

The inclusion behavior of an intramolecular charge transfer (ICT) fluorescent probe namely; 2-[3-(4-dimethylamino-phenyl)-allylidene]-tetralone (DMAPT) in organized assemblies of aqueous micellar, α- and ß-cyclodextrins (CDs) and bovine serum albumin (BSA) pockets have been studied using steady-state absorption and fluorescence spectroscopy. The fluorescence characteristics (energy and intensity) of DMAPT are highly sensitive to the properties of the medium. The ICT maximum is strongly blue-shifted with a great enhancement of the fluorescence intensity upon addition of different surfactants, confirming the solubilization of DMAPT in the hydrophobic micellar assembly. In addition, the fluorescence of DMAPT is more sensitive to the nature and concentration of the added CDs. In α- or ß-CD solutions, the fluorescence intensity increases strongly (by 6 and 23 orders of magnitude, respectively). Upon encapsulation in the CD cavity, the molecular flexibility decreases due to the geometrical restrictions of the CD nanocavity which decreases the non radiative transition via the free rotation around the single and/or double bonds of the butadiene bridge. This was supported by finding that the fluorescence quantum yield of DMAPT increases with increasing the viscosity of the medium. The binding constants of DMAPT with micelles, α- and ß-CD solutions have been calculated and were found to be highly dependent on the nature of the used surfactants or CDs. The thermodynamic parameters have been also determined and the difference in magnitude between the formed α- and ß-CD-DMAPT inclusion complexes is discussed on the basis of the cavity size. Finally, the binding constant of DMAPT with bovine serum albumin was calculated, indicating the relative stability of the DMAPT-BSA complex. The energy transfer distance between BSA as a donor and DMAPT as an acceptor was obtained following the fluorescence quenching of BSA by DMAPT, via resonance mechanism as a quencher.