Experimental and theoretical studies of the efficiency of metal-organic frameworks (MOFs) in preventing aluminum corrosion in hydrochloric acid solution.

Aluminum corrosion inhibitors "{[CuI (CN)2(phen) CuII (CN)2(phen)]5H2O},(MOF1) and {[CuI(CN)2(phen)CuII(CN)2(phen)]5H2O}@TiO2 (MOF1@TiO2) were studied in one molar HCl solution". The ML results for three different temperatures (25-45 °C) were compared with the results of PDP and EIS analyses. The adsorption of inhibitors on Al surfaces has been calculated and discussed by a Langmuir isotherm. The inhibitors that were created showed great effectiveness, with a noticeable increase in their inhibitory efficiency as the dosage was raised and the temperature was lowered. Inhibition efficiency each amounted to 88.6%, 84.5% at 400 ppm and 25 °C for MOF1@TiO2 and MOF1, respectively. Analyzing the polarization curves of synthesized inhibitors revealed that they were mixed-type inhibitors. Al was found to be surface inhibited when coated with a thin film of inhibitors, and "Al's surface morphology was assessed by different techniques such as scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and atomic force microscope (AFM)". "Theoretical models like quantum chemical and molecular dynamics simulation authenticated the experimental observation". The MOFs exhibit exceptional corrosion resistance against Al when exposed to acidic environments, according to several tests.

Experimental and computational approaches of methoxy naphthylbithiophene derivatives and their use as corrosion protection for carbon steel in acidic medium.

The inhibition efficiency and adsorption affinity were investigated for two novel compounds, namely: 6-methoxy-2-naphthyl-[2, 2'-bithiophene]-5-carboxamidine hydrochloride salt (MA-1440) and 5'-(4-chlorophenyl)-2, 2'-bifuran-5-carboxamidine hydrochloride salt (MA-1456). The inhibition study was conducted on carbon steel surface in 1.0 M HCl with different inhibitor doses and different temperature levels, to investigate the optimum dose and preferable temperature. The performed investigation included chemical, electrochemical, instrumental, and quantum computation techniques. A chemical technique was accomplished by using weight-loss measurements. Different factors were studied using weight-loss measurements in order to reach the maximum inhibition efficiency. The adsorption study revealed that the examined inhibitors obey the Langmuir adsorption isotherm and are chemically adsorbed on the steel surface. The electrochemical measurements were accomplished through the electrochemical impedance (EIS) and potentiodynamic polarization (PDP) techniques. Based on the electrochemical measurements, the examined compounds were categorized as mixed inhibitors. The instrumental examination using different techniques namely: scanning electron microscope (SEM), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) confirmed that the considered inhibitors are excellently adsorbed over the carbon steel surface. The extent of the adsorption affinity of these compounds on the carbon steel surface was studied theoretically using quantum computations and Monte Carlo simulation. The theoretical investigation results of quantum chemistry were validated with those obtained by chemical and electrochemical methodologies. All investigations prove that, the tested compounds were adsorbed chemically on the steel surface and achieved maximum inhibition efficiency of, 94.69% and 90.85% for M-1440 and MA-1456, respectively, at the optimum concentration 30 [Formula: see text] 10-6 mol L-1 and temperature 328 K.

Chemical, electrochemical and surface studies of new metal-organic frameworks (MOF) as corrosion inhibitors for carbon steel in sulfuric acid environment.

The effects of [Co2 (SCN) 4(hmt)2(H2O)6. H2O] (SC1) and [Co (CN)6 (Me3Sn)3(H2O). (qox)] (SCP2) MOF as corrosion inhibitors on C-steel in 0.5 M sulfuric acid solutions are illustrated utilizing mass reduction (MR), electrochemical [potentiodynamic polarization (PP), and AC electrochemical impedance (EIS)]. The experiments revealed that as the dose of these compounds rose, the inhibition efficacy (IE percent) of C-steel corrosion improved, reaching 80.7-93.1% at dose 25 × 10-6 M for SC1 and SCP2, respectively. IE percent, on the other hand, dropped as the temperature range grew. SC1was adsorbed physically and chemically (mixed adsorption) but SCP2 was adsorbed physically on the surface of C-steel and conformed to the Langmuir adsorption isotherm equation. The PP studies revealed that these compounds act as mixed kind inhibitors. To establish the morphology of the inhibited C-steel surface, scanning electron microscopy (SEM), energy transmitted X-ray (EDX), and atomic force microscopy (AFM) studies were used. All tested experiments were in good agreement.

Aromatic ring size effects on the photophysics and photochemistry of styrylbenzothiazole.

The effect of ring size on the photophysics and photochemistry of styrylbenzothiazole has been investigated via systematic replacement of the phenyl ring of 1-phenyl-2-(2-benzothiazolyl)ethene with naphthyl and phenanthryl rings. Steady state absorption and fluorescence techniques have been employed to record the spectra in a variety of solvents, in conjunction with density functional theory (DFT) calculations, to probe absorption spectra and other properties of relevance to photo-excitation. Important experimental parameters were determined, such as fluorescence quantum yield and quantum yields of photochemical E-Z isomerisation. In addition, the computed potential energy surfaces of the ground and excited states were constructed using DFT/TD-DFT methods that showed that the photo-reaction is based on an adiabatic mechanism, in the sense that the reaction occurs via the excited-state potential energy surface. Based on the significant blue shift of the Z-isomer absorption maximum relative to that of the E-isomer, and the high percentage of Z-isomers in the photo-stationary state, these compounds may serve as potential promising candidates for optical data storage applications.

Synthesis, spectral, antimicrobial and antitumor assessment of Schiff base derived from 2-aminobenzothiazole and its transition metal complexes.

N-(thiophen-2-ylmethylene)benzo[d]thiazol-2-amine Schiff base (L) derived from 2-aminobenzothiazole and 2-thiophenecarboxaldehyde was synthesized and characterized using elemental analysis, IR, mass spectra, (1)H NMR and UV-vis spectra. Its complexes with Cu(II), Fe(III), Ni(II) and Zn(II) were prepared and isolated as solid products and characterized by elemental and thermal analyses, spectral techniques as well as magnetic susceptibility. The IR spectra showed that the Schiff base under investigation behaves as bidentate ligand. The UV-vis spectra and magnetic moment data suggested octahedral geometry around Cu(II) and Fe(III) and tetrahedral geometry around Ni(II) and Zn(II). In view of the biological activity of the Schiff base and its complexes, it has been observed that the antimicrobial activity of the Schiff base increased on complexation with the metal ion. In vitro antitumor activity assayed against five human tumor cell lines furnished the significant toxicities of the Schiff base and its complexes.