Acta Chimica Slovenica最新文献

A new tetranuclear copper(II) complex [Cu4L2(N3)2(CH3OH)2](NO3)2·4CH3OH (1) and a new trinuclear zinc(II) complex [Zn3L2(CH3COO)2] (2) have been prepared from the bis-Schiff base N,N'-bis(4-bromosalicylidene)-1,3-propanediamine (H2L) with copper nitrate and zinc acetate, respectively, in the presence of sodium azide. The complexes were characterized by elemental analysis, IR and UV-Vis spectroscopy. Molecular structures of both complexes were confirmed by single crystal X-ray determination. The Cu(II) atoms in complex 1 are bridged by phenolate oxygen atoms and end-on azide ligands. The Zn(II) atoms in complex 2 are bridged by phenolate oxygen atoms and acetate ligands. The Cu(II) atoms in complex 1 are in square planar and square pyramidal coordination. The Zn(II) atoms in complex 2 are in square pyramidal and octahedral coordination. The Schiff base ligand coordinates to the metal atoms through two phenolate O and two imino N atoms. The biological assay reveals that the copper(II) complex has effective urease inhibition.

The cellulose is the most abundant and renewable polymer in nature. It is characterized by its biodegradability that can help to establish a friendly environment. The main objective of this study is intended to characterize the nanocellulose obtained from waste date palm,  including the dried palms (DP) and the fresh palms (FP) by implementing chemical methods (hydrolysis with H2SO4). Physical properties, morphology, the elemental composition and the thermal stability were determined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), zeta sizer, scanning electron microscopy (SEM), whereas energy dispersive X-ray (EDX) and thermogravimetric analysis (TGA), respectively. FTIR, SEM and EDX results, revealed the effective removal of impurities, hemicellulose and lignin. Palm sample residues contained 35.99% of cellulose and 33.12% of cellulose nanocrystals (CNC) for DP, and 36.17% of cellulose and 34.35% of CNC for FP. The CNCs have higher crystallinity than the raw fibers and Zeta sizer was between 25 and 1150 nm. TGA analysis showedthat DP exhibited greater thermal resistance.

Association behavior between quinizarin (1,4-dihydroxyanthraquinone), an analogue of the chromophore of anthracycline anticancer drugs and sodium dodecyl sulfate (SDS) micelles in the presence of glucose, NaCl and urea additives was studied using absorption spectroscopy and conductometric techniques. The spectral results indicate an increase of binding constant and partition coefficient values in the presence of glucose and NaCl whereas the addition of urea leads to a decrease of binding strength and quinizarin partitioning into SDS micelles. Thus, the rise of NaCl and glucose concentrations is favorable for the quinizarin distribution into SDS micelles. From electrical conductivity measurements it was found that the critical micelle concentration (CMC) of SDS/quinizarin system decreases by adding NaCl and glucose whereas urea has not influence on the micelization process at the concentrations used in the present study. Since biologically compounds like glucose, NaCl and urea are found in the human body, the attained outcomes can be important in finding of effective drug delivery systems.

The aim of this study is to optimize the extraction process and characterize the proteins found in fenugreek seeds. The water and oil holding capacities, coagulated protein content, foaming and emulsification properties of the isolated proteins at all extraction conditions were investigated. Also, solubility, molecular weights, structural and thermal properties were determined. In the extraction processes carried out at different pHs (pH 6.0-12.0) and solid:solvent ratios (20-60 g/L), it was determined that the highest extraction yield (94.3±0.3%) was achieved when the pH was 11.47 and the solid-solvent ratio was 34.50 g/L. Three distinct bands (46, 59 and 80 kDa) in the range of 22-175 kDa were determined for the fenugreek seed protein isolate obtained at optimum extraction conditions. Protein secondary structures were achieved using Fourier Transform Infrared (FT-IR) spectra and it was determined that β-sheet structures were highly present. In addition, denaturation temperatures and denaturation enthalpy were calculated as ~119°C and 28 mJ/g, respectively.

1H-indole-2,3-dione 3-[4-(4-sulfamoylphenyl)thiosemicarbazones] (6a-j) were evaluated against Para-influenza-3, Reovirus-1, Sindbis, Coxsackie B4 and Punto Toro viruses. New 1-methyl-1H-indole-2,3-dione 3-[4-(4-sulfamoylphenyl)thiosemicarbazones] (7a-c) were synthesized to evaluate the contribution of methyl substitution at position 1- of the indole ring to antiviral activity. The test results showed that compounds 5-trifluoromethoxy- substituted 6c (EC50: 2-9 µM) and 5-bromo- substituted 6f (EC50: 2-3 µM) have non-toxic selective antiviral activity while not all standards are active against Reovirus-1. Molecular docking studies of 6c and 6f were carried out to determine the possible binding positions with Reovirus-1. Trifluoromethoxy and bromine substitutions at position 5- of the indole ring provided selective antiviral activity, while methyl substitution at position 1- of the indole ring significantly decreased the activity and increased toxicity against Reovirus-1.

A Quantitative structure-retention relationship (QSRR) analysis has been carried out on the chromatography parameters of lipophilicity of selected spirohydantoins. Multiple linear regression (MLR) was applied for construct the QSRR models. The chromatographic parameters of lipophilicity were determined by reversed-phase thin-layer chromatography. Chromatographic analyses were performed on C-18 modified silica gel with a two-component mobile phase consisting of water and protic organic solvent (ethanol, n-propanol, i-propanol, or t-butanol) in different ratios. QSRR models were built and for additional four aqueous mobile phases: acetone-water, acetonitrile-water, tetrahydrofuran-water, and 1,4-dioxane-water (results published before). In total, chromatographic lipophilicity parameters obtained for two types of organic solvents was subject of the QSRR. The predictive ability of each model was defined by an internal validation coefficient. The best QSRR model for predicting the chromatographic parameter of lipophilicity was obtained for tetrahydrofuran as an organic solvent.

Dear readers of Acta Chimica Slovenica, In this year Acta Chimica Slovenica, the journal published by Slovenian Chemical Society, is celebrating 70th anniversary.

This article describes the synthesis of nanosilica-cysteine composite (SiO2-Cys) and its application as a sorbent for arsenic(III) removal from different aqueous media. Attenuated total reflectance-Fourier-transform infrared spectroscopy, scanning and transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis were applied to characterize SiO2-Cys. Using the batch technique, sorption of As(III) ion by SiO2-Cys was studied, and the effects of pH, sorbent dosage, temperature, initial concentration, and contact time were all taken into consideration. According to kinetic studies, the pseudo-second-order equation adequately described the sorption of the As(III) ion. The spontaneity of the sorption process on SiO2-Cys is suggested by the negative values of Gibbs free energy (G°). Positive values of enthalpy (ΔH°) indicate the endothermic adsorption process and the positive values of entropy (ΔS°) for As(III) ions adsorption imply that the adsorption involves increasing randomness. The Langmuir model, which has a maximum sorption capacity for SiO2-Cys of (66.67 mg/g) at 25°C, provided a better fit to the sorption isotherm.