Acta Chimica Slovenica最新文献

A mononuclear methyl maltolate (Hmm) coordinated oxidovanadium(V) complex [VOL1(mm)] (1), and a mononuclear ethyl maltolate (Hem) coordinated oxidovanadium(V) complex [VOL2(em)] (2), where L1 and L2 are the dianionic form of N'-(2-hydroxy-5-methylbenzylidene)-3-trifluoromethylbenzohydrazide (H2L1) and N'-(2-hydroxy-5-methylbenzylidene)-4-trifluoromethylbenzohydrazide (H2L2), respectively, have been prepared. The hydrazones and the complexes were characterized by elemental analysis, FT-IR and UV-Vis spectra. Structures of H2L1 and the two complexes were further characterized by single crystal X-ray diffraction. The two complexes have similar structures, with the V atoms in octahedral coordination. The hydrazones behave as ONO tridentate ligands with the V atoms. Both complexes have interesting properties on the catalytic epoxidation of cyclooctene.

Efficiencies of direct ozonation and hydroxyl radical oxidation by Fenton process were compared, aiming to improve biotreatability of antibiotics contaminated water (tiamulin, amoxicillin and levofloxacin).  Biodegradability, COD (chemical oxygen demand) and TOC (total organic carbon) were measured before and after applying oxidative process. It was confirmed that significantly smaller molar dose of ozone (1.1 mgO3 / mgatb) against the hydrogen peroxide (17 mgH2O2 / mgatb), deliver comparable improvements of biodegradability; Tiamulin biodegraded up to 60 %, levofloxacin close to 100 %. Ozonation removed more TOC (10%, 29% and 8% for tiamulin, levofloxacin and amoxicillin, respectively) than Fenton process. This is confirming mineralization of antibiotics, not only biodegradable intermediates formation. In terms of costs, ozonation is more feasible in oxidizing complex antibiotics in water, as it targets functional groups which carry antimicrobial properties. This brings not only improved biodegradability needed for a conventional biological treatment plant, but also reduces long-term impacts of the antibiotics in the environment.

One of the disadvantages of voltammetric analysis is the significant amount of sample required for electrolysis in the cell. In this paper a methodology close to adsorption stripping voltammetry was proposed to solve this problem at an analysis of two azo dyes - Sunset Yellow FCF and Ponceau 4R. As a working electrode, a carbon-paste electrode modified with β-cyclodextrin, a cyclic oligosaccharide that can form supramolecular complexes with azo dyes was proposed. The redox behavior of Sunset Yellow FCF and Ponceau 4R, the number of electrons, protons, and charge transfer coefficients onto the proposed sensor have been studied. Using square-wave voltammetry, the conditions for the determination of two dyes were optimized. Under the optimal conditions the calibration plots are linear in the ranges 71-565 µg/L and 189-3024 µg/L for Sunset Yellow FCF and Ponceau 4R, respectively. Finaly, the new sensor has been tested for square-wave voltammetric determination of Sunset Yellow FCF and Ponceau 4R in soft drinks, and RSD values (max. 7.8 and 8.1%) indicated satisfactory precision for both analyzed samples.

The acid catalyzed hydrolysis of the N-(p-substitutedphenyl) phthalimides in three different acids was investigated at 50.0±0.1°C. Two different antioxidant activity tests as DPPH• and ABTS•+ scavenging activities, and three various enzyme inhibition activity tests as urease, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) inhibition activities, were applied. Compound 3c (2.03 µg/mL ) has higher antioxidant activity than other compounds and standards according to DPPH test. In AChE assay, compounds 3a and 3b (13.13 and 9.59 µg/mL) has higher enzyme inhibition activity than the standard Galantamine (14.37 µg/mL). In BChE and urease tests, all compounds (6.84-13.60 and 10.49-17.73 µg/mL) have higher enzyme inhibition activity than the standard Galantamine (49.40 µg/mL) and thiourea (26.19 µg/mL), respectively. The molecule interaction for each of the three compounds with the active sites of AChE, BChE, and urease enzymes was examined via molecular docking simulations.

Amiodarone (AMD) is a powerful antiarrhythmic drug preferred for treatments of tachycardias. Brain can be affected negatively when some drugs are used, including antiarrhythmics. S-methyl methionine sulfonium chloride (MMSC) is a well-known sulfur containing substance and a novel powerful antioxidant. It was intended to investigate the protective effects of MMSC on amiodarone induced brain damage. Rats were divided to four groups as follows, control (given corn oil), MMSC (50 mg/kg per day), AMD (100 mg/kg per day), AMD (100 mg/kg per day) + MMSC (50 mg/kg per day). The brain glutathione and total antioxidant levels, catalase, superoxide dismutase, glutathione peroxidase, paraoxonase, and Na+/K+-ATPase activities were decreased, lipid peroxidation and protein carbonyl, total oxidant status, oxidative stress index and reactive oxygen species levels, myeloperoxidase, acetylcholine esterase and lactate dehydrogenase activities were increased after AMD treatment. Administration of MMSC reversed these results. We can conclude that MMSC ameliorated AMD induced brain injury probably due to its antioxidant and cell protective effect.

Two copper(II) complexes of 4-chloro- and 4-dimethylaminobenzaldehyde nicotinic acid hydrazones were prepared and characterized by elemental analysis, mass spectrometry, infrared and electron spectroscopy and conductometry. These rare examples of bis(hydrazonato)copper(II) complexes are neutral complex species with copper(II) center coordinated with two monoanionic bidentate O,N-donor hydrazone ligands coordinated in enol-imine form. The interaction of hydrazone ligands and corresponding copper(II) complexes with CT DNA and BSA was investigated. Copper(II) complexes are slightly effective in binding the DNA than pristine hydrazones. The results indicate groove binding or moderate intercalation which are not significantly affected by the nature of substituent at hydrazone ligands. On contrary, affinities of two copper(II) complexes toward BSA significantly differs and depends on the nature of the substituent, however in absence of thermodynamic data difference in nature of binding forces cannot be excluded. The complex bearing electron-withdrawing 4-chloro substituent has larger affinity toward BSA compared to 4-dimethyamino analogue. These findings were theoretically supported by molecular docking study.

Four new complexes of copper(II), nickel(II) and zinc(II), [CuL2] (1), [Ni3L2(4-BrSal)2(CH3COO)2(CH3OH)2]·2CH3OH (2), [ZnBr2(HL)2] (3) and [ZnL(dca)]n (4), where L is 5-bromo-2-((cychlopentylimino)methyl)phenolate, HL is the zwitterionic form of 5-bromo-2-((cychlopentylimino)methyl)phenol, 4-BrSal is the monoanionic form of 4-bromosalicylaldehyde, dca is dicyanamide anion, were synthesized and characterized by elemental analysis, IR and UV-Vis spectroscopy. The structures of the complexes were further confirmed by single crystal X-ray structure determination. Complex 1 is a mononuclear copper(II) compound, with a crystallographic two-fold rotation axis symmetry. The Cu atom is in distorted square planar coordination. Complex 2 is a trinuclear nickel(II) compound, with an inversion center symmetry. The Ni atoms are in octahedral coordination. Complex 3 is a mononuclear zinc(II) compound, while complex 4 is a dca bridged polymeric zinc(II) compound. The Zn atoms are in tetrahedral coordination. The compounds were assayed for their antimicrobial activities.

For carbon steel X70 in a 1 M hydrochloric acid solution, Scorzonera undulata acetate extract (SUAc) was investigated as an ecological corrosion inhibitor. The anti-corrosion effect of Scorzonera undulata extract is studied using potentiodynamic polarization analysis and electrochemical impedance spectroscopy (EIS). The polarization curves clearly show that the extract is an excellent mixed inhibitor. Our findings show that the maximum inhibition efficiency of 83% has been found with inhibitor concentration up to 400 mg/L at 298 Kelvin. The Langmuir isotherm is followed by the inhibitor's adsorption on the steel surface and physical adsorption was discovered to be the mechanism. To understand the inhibitory mechanism, thermodynamic parameters (∆G°ads) and activation parameters (Ea, ∆Ha, and ∆Sa) were determined. Scanning electron microscopy (SEM) and X-ray photoelectron spectrometry studies of the surface chemistry and morphology are included to this investigation. The results obtained from chemical and electrochemical measurements, confirm that a protective film is formed on the carbon steel surface.

In this study, activated carbon (AC) was prepared from pistachio nut shell precursor as agricultural by-product. The prepared AC was used to synthesize an efficient nanocomposite via loading of the copper metal and magnetic nanoparticles (Cu-MAC@C4H8SO3H NCs) onto its structure. The structure of the nanocatalyst was characterized by different methods such as FT-IR, TEM, EDS, XRD, VSM, and TGA analysis. The catalytic activity of the prepared composite was tested in a special C-S coupling, namely with the reaction of 2-mercapto-3-phenylquinazolin-4(3H)-one with iodobenzene or bromobenzene. The products of the aryl thioquinazoline derivatives were obtained in good yields and in short reaction times and the products were characterized with 1H, 13C NMR and CHNS analysis. On the other hand, with easy and high recovery of Cu-MAC@C4H8SO3H NCs through magnetic separation, a simple and green method to enhance the efficiency of the nanocatalyst has been provided. The nanocatalyst was reused in the next reaction in up to five cycles without obvious activity decrease.