Water-methanol Medium Research Articles

Synthesis, characterization and anti-microbial activities of mixed ligand complexes of sulphamethoxazole-urea with cobalt (II) and zinc (II) ions in water-methanol medium

Novel mixed ligand metal complexes of Zinc (II) and Cobalt (II) were respectively synthesized with sulphamethoxazole-urea in a water-methanol medium by refluxing method and characterized gravimetrically (using Mohr’s method for chloride and sulfur determination); the purity of the complexes through melting point determination; the functional groups present by infrared spectroscopy. The results predicted the coordination of the metals to the ligand through the amide group and oxygen atom of the sulphamethoxazole-urea bidentate. Solubility tests revealed that metal complexes were soluble in dimethyl sulphoxide acetone and ethanol. The metal complexes synthesized were also screened for their activities against some bacteria (Xanthomonas sp, E. coli, B. aureus, P. syrugiae, Staphylococcus sp., Bacillus aureus, and P. aureus) and some fungi (S. rolfsil, C. indimutiaum, C. capsicia) using Agar Disc diffusion principle. The metal complexes of sulphamethoxazole (SMX) and mixed ligands show little sign of bacteria inhibition but are more effective on fungi. The results indicate that the mixed ligand metal complexes were more biologically active than the free ligand. The better biological activity resulted in the MLC of Zn.

Synthesis, characterization and anti-microbial activities of mixed ligand complexes of sulphamethoxazole-urea with cobalt (II) and zinc (II) ions in water-methanol medium

Synthesis, characterization and anti-microbial activities of mixed ligand complexes of sulphamethoxazole-urea with cobalt (II) and zinc (II) ions in water-methanol medium

Spectrophotometric methods for quantitative determination of sotalol in tablets

The aim of the work. To develop a method for spectrophotometric determination of sotalol with diazonium salts. Establish optimal conditions for the quantitative determination of sotalol in drugs. Validate the developed methodology. Materials and methods. Reagents and solvents used in the study were: diazole red 2J (obtained from NVF “Sinbias”), tablets “Sotalol Sandoz” 40 mg (Salyutas Pharma GmbH, series JZ1188), “Sotalol Sandoz” 80 mg (Salyutas Pharma GmbH, series KA0464) and “Sotalol Sandoz” 160 mg (Salyutas Pharma GmbH, series JY3504), methanol (LAB-SCAN, Ireland, batch № 5120/13), sodium carbonate (Sinbias) and purified water were also used. Analytical equipment: spectrophotometer “SPECORD-200” (Analytic Jena AG, Germany), scales laboratory electronic RADWAG XA 210.4Y, bath ultrasonic Sonorex Digitec DT100H, laboratory glassware of class A. All studies were conducted in the experimental pharmaceutical research department of the scientific medical laboratory center (SMLC) of the Zaporizhzhia State Medical University. Results and discussion. The technique of spectrophotometric determination of the quantitative content of sotalol based on its reaction with red diazole in water-methanol medium has been developed. The stoichiometric ratios of the reactive components as 1:1 were obtained by the methods of continuous changes and the saturation method. Validation of the developed on such indicators as linearity, precision, correctness and robustness is carried out. Based on these data, the developed method is correct and could be used in the quality control departments of chemical and pharmaceutical companies. Conclusions. A method of quantitative spectrophotometric determination of sotalol in the tablet dosage form “Sotalol Sandoz” 40 mg, “Sotalol Sandoz” 80 mg and “Sotalol Sandoz” 160 mg of industrial production was developed, validation characteristics were investigated: linearity, precision, correctness, range of application and robustness

Microwave-assisted one-pot hydrothermal synthesis of V and La co-doped ZnO/CNTs nanocomposite for boosted photocatalytic hydrogen production

In this work, vanadium and lanthanum co-doped ZnO/CNTs (VL-ZnO/CNTs) composites of large surface area and enhanced light assimilation range were produced for boosted hydrogen evolution from water. The photocatalysts were investigated for their morphological, structural, optical and photocatalytical properties. The photocatalytic activity of the composites was evaluated in pure water and in a mixture of water and methanol under simulated sunlight and visible light illumination. Under simulated sunlight irradiation, the maximum hydrogen generation rate of 925 μmolh−1g−1 from a combination of water and methanol was attained, which is almost 7 times higher than hydrogen generation rate achieved with pure ZnO. The VL-ZnO/CNTs photocatalyst resulted in hydrogen production rate of 267 μmolh−1g−1 from the water-methanol medium when exposed to visible light. This rate was about 3.5 folds lower than that achieved under simulated sunlight illumination. This improvement in hydrogen production rate is attributed to large surface area, high photo-response, better separation/transportation of the charge carriers and synergistic impact of V, La and CNTs in the designed photocatalyst.

Development and validation of spectrophotometric method for quantitative determination of carvedilol in tablets

INTRODUCTION: Carvedilol is in a class of medications called beta blockers. It works by relaxing blood vessels and slowing heart rate to improve blood flow and decrease blood pressure. AIM: The aim of this article is to develop a spectrophotometric method for the quantitative determination of carvedilol with diazonium salts, establish optimal conditions for the quantitative determination of carvedilol in drugs, and validate the developed methodology. MATERIALS AND METHODS: All studies were conducted on the basis of the experimental pharmaceutical research department of the scientific medical laboratory center (NMLC) of the Zaporozhye State Medical University. Reagents and solvents: 6.25 mg carvedilol tablets (PRANAPHARMJSC, Samara, series 20717), 12.5 mg Carvedilol Canon tablets (Canonpharma Production CJSC, Russia, series 060517), 25 mg Talliton tablets (EGIS Pharmaceuticals PLC, Hungary, series 473D0617), 25 mg Carvedilol-KV tablets (OJSC Kyiv Vitamin Plant, Kyiv, Ukraine, series EF 411017), diazol red 2G (NVF Sinbias), acetone, methanol, ethanol, isopropanol, water. Analytical equipment: SPECORD-200spectrophotometer (Analytic Jena AG, Germany), ULAB S131UV spectrophotometer, RADWAG XA 210.4Y electronic laboratory scales, Sonorex Digitec DT100H ultrasonic bath. RESULTS: The technique of spectrophotometric determination of the quantitative content of carvedilol based on its reaction with red diazole in water-methanol medium has been developed. The 1:1 stoichiometric ratios of the reactive components were obtained by the methods of continuous changes and the saturation method. CONCLUSION: A spectrophotometric method of analysis for the quantitative determination of carvedilol in tablets has been developed. The method is simple, fast, accurate, and reliable. This has been proven by verification characteristics (linearity, precision, correctness and sustainability). The developed methodology is correct and can be used in the chemical and pharmaceutical industries.

Synthesis, characterization and antimicrobial evaluations of mixed ligand complexes of sulphamethaxole and metronidaxole with some transistion metals (Zn, Co, Cu and Fe) in water methanol medium

Sulfamethoxazole and metronidazole are antibiotics use for the treatment of various bacterial infections. Their use as ligand is very prominent in formation of metal complexes. The transition metal complexes are synthesized by reaction of Sulfamethoxazole and metronidazole with metals such Mn(II), Cu(II), Fe(II) and Ni(II). The synthesized metal complexes are tested as antibacterial and antifungal. The antimicrobial activity of the complexes displays good potency against some microorganism such as Xanthomonas axonopodis, Streptococcus faecalia, Salmonella entrica, Claribacter michiganense, Xanthomonas phaseolin for bacteria and S.roofisii, M.phonoides, C.lindimuthianum for the fungi, it is revealed that all copper complexes show stronger antibacterial activity than the free drugs. The spectroscopic properties of the complexes were investigated using UV/visible and FT-IR which show metal-charge from 3d to 3s transition in which the transition state shows that they are octahedral geometry and their coordination site respectively. Their percentage yield was moderately high and producible. The complexes synthesized have higher inhibitory activities than the free ligand. The drug resistance in microbes is resulting in the incompetence of available drugs to care for the infections. The thermal analysis shows that the complexes are stable.

In neutralized medium five new Ca(II), Zn(II), Fe(III), Au(III) and Pd(II) complexity of ceftriaxone antibiotic drug: Synthesis, spectroscopic, morphological and anticancer studies

A five ceftriaxone antibiotic (ctx) complexes with Ca(II), Zn(II), Fe(III), Au(III) and Pd(II) metal ions were synthesized by 1:1 M ratio between of ceftriaxone hydrated sodium salt (Na2ctx) with CaCl2, ZnCl2, FeCl3.6H2O, AuCl3 and PdCl2 metal salts in water–methanol medium. The complexes were well characterized dependent on the microanalytical (C,H, N), molar conductance, (FTIR, Raman, 1HNMR and UV–Vis) spectroscopies, and magnetic measurements. The surface morphology and calculation of particle size of ceftriaxone complexes were performed based on SEM, TEM and X-ray diffraction. Calcium(II), zinc(II), and iron(III) complexes are six-coordinate with distorted octahedral geometry, while gold(III) and palladium(II) are four-coordination mode. The ceftriaxone drug acts as a tetradentate ligand towards five metal ions through N (amino group) and O (triazine, β-lactam carbonyl, and carboxylate groups) with the molecular formulas [Ca(ctx)(H2O)2].5H2O (1), [Zn(ctx)(H2O)2].7H2O (2), [Fe(ctx)(H2O)(Cl)].7H2O (3), [Au(ctx)].Cl. 4H2O (4) and [Pd(ctx)].3H2O (5). The cytotoxicity assays study of gold(III) complex against colon carcinoma cells (HCT-116) and hepatocellular carcinoma cells (HepG-2) showed that the 50% inhibitory concentration (IC50) of [Au(ctx)].Cl.4H2O against HepG-2 cell line is 8.53 μg higher than that of HCT-116 cell line 20.5 μg.

Thermodynamic characteristics of the adsorption of benzene derivatives from water—organic eluents on porous graphite-like adsorbent under conditions of equilibrium HPLC

Thermodynamic characteristics of the adsorption of benzene and its derivatives on the surface of a porous graphite-like Hypercarb adsorbent from binary polar eluents have been experimentally determined under the conditions of equilibrium HPLC at various temperatures. The retention on Hypercarb columns is generally maintained by non-specific intermolecular interactions with the flat graphite-like surface and depends on the size of their molecular area. The contributions of various functional groups to the heat and entropy of adsorption were determined. The influence of solvation effects on the values of adsorption parameters was demonstrated. The replacement of methanol in the mobile phase composition with acetonitrile leads to an increased influence of the solvatation effects, while for the water-acetonitrile eluent, there were no any observed correlations of parameters of the adsorption on Hypercarb from a water-methanol medium with the data acquired on gas phase adsorption on graphite. The entropy values of adsorbates in their solvated state have been for the first time determined for eluents of the different polarities and compared with the entropy values for the state of pure liquid, which allowed us to clarify the nature of solvatation of the considered compounds in the polar eluent. Using the adsorption of compounds at issue as an example, the effect of enthalpy-entropy compensation was investigated, and the values of compensation temperatures were estimated.

Preparation of Modified Chitosan Microsphere-Supported Copper Catalysts for the Borylation of α,β-Unsaturated Compounds

Chitosan microspheres modified by 2-pyridinecarboxaldehyde were prepared and used in the construction of a heterogeneous catalyst loaded with nano-Cu prepared by a reduction reaction. The chemical structure of the catalyst was investigated by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). Under mild conditions, such as no ligand at room temperature, the catalyst was successfully applied to catalyze the borylation of α,β-unsaturated receptors in a water-methanol medium, yielding 17%–100% of the corresponding β-hydroxy product. Even after repeated use five times, the catalyst still exhibited excellent catalytic activity.

Determination of Biogenic Amines at Low μg L–1 Levels as Acetylacetone Derivatives by RP-HPLC with UV-Visible Detection in Expired Apple Juice Samples

An accurate and sensitive method for trace quantification of three biogenic amines in expired apple juice samples based on reversed-phase liquid chromatography (RP-HPLC) with UV-visible detection is described. Biogenic amines including cadaverine, histamine, and tyramine, were converted to their acetylacetone derivatives in water-methanol medium. The proposed method involves a pre-column derivatization of species followed by RP-HPLC separation with Thermo Hypersil Gold reversed-phase column and UV detection at 315 nm. A flow rate of 0.9 mL min-1 was used in the proposed method. An efficient separation of biogenic amines was successfully performed in 11 min with a good resolution using 35:65% (v/v) acetonitrile-water mixture as the mobile phase. Detection limits of 0.03, 0.23, and 0.08 ∆g L-1 were obtained for cadaverine, histamine and tyramine, respectively. The proposed method has been successfully applied for the analysis of two different commercially available expired apple juice samples. Recovery rates between 98.78 and 102.12% were obtained with an RSD of 0.16-1.65% for the analysis of 20 mL of expired apple juice samples indicating that the recoveries of biogenic amines were very satisfactory.

Supramolecular interactions through lone pair(lp)–π and hydrogen bonding in cobalt(III) and manganese(II) derivatives of N,N′-dimethylvioluric acid: A combined experimental and theoretical study

The reactivities of cobalt(II) and manganese(II) salts toward HDMV (N,N′-dimethylvioluric acid monohydrate) were studied. Reaction of cobalt(II) chloride hexahydrate with HDMV in water–methanol medium at pH=8.0 led to the formation of a cobalt(III) complex [CoIII(DMV)3]·0.5H2O (1), whereas the interaction of manganese(II) chloride tetrahydrate with HDMV under similar reaction conditions afforded [MnII(H2O)6](DMV)2 (2). Dimethylviolurate anion behaves as a bidentate ligand in 1 and counteranion in 2. Both compounds were characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, cyclic voltammetry and thermogravimetric analysis. Presence of Co(III) in 1 indicates the aerial oxidation of the cobalt(II) precursor. In 1, Co(III) adopts a distorted octahedral [CoN3O3] coordination environment through bonding to the three dimethylviolurato anions. In 2, the [Mn(H2O)6]2+ cations and (DMV)− anions are assembled by multiple hydrogen bonds into a complex 3D H-bonded network. It was analyzed from the topological viewpoint, disclosing a binodal 4,8-connected underlying net with the flu (fluorite) topology. Electrochemical studies reveal that the compounds undergo a quasi-reversible one electron metal centered redox process. DFT studies were carried out to analyze the supramolecular assemblies in the solid state structures, especially lone pair(lp)–π interactions in 1 and H-bonding network in 2.

Surface structure of stimuli-responsive polystyrene particles prepared by dispersion polymerization with a polystyrene/poly(l-lysine) block copolymer as a stabilizer

A block copolymer composed of polystyrene and poly(α-l-lysine hydrobromide) (PLL) segments was used as a stabilizer for dispersion polymerization of styrene in water–methanol medium to give narrowly-distributed polystyrene particles in the size range from 0.36 to 1.09 μm, on which the PLL segment was grafted with a surface density of 0.2–3.4 l-lysine residue/nm2. We investigated effects of polymerization time, stabilizer concentration, segmental composition of the block copolymer, and composition of the medium on surface structure and particle size of the affording particles. Interestingly, we obtained an experimental evidence that the surface density of the PLL clearly depends on structural parameters of the stabilizer and various polymerization conditions. Based on the dependence, it was possible to control the surface density of the narrowly-distributed particles within the range between the minimum and the maximum density limits of the graft chain by changing the structure of the stabilizer and polymerization conditions. Conformation of the PLL, which underwent a helix–coil transformation with an increase in water composition of the medium, had a strong effect on the surface structure, the size, and property of the resulting particles. Further modification of the particle surface was possible by utilizing the amino groups in the PLL graft.

Naphthazarin, a simple model of important antitumor agents in a facile size-tunable synthesis of gold nanoparticles

2,3-Dihydro-5,8-dihydroxynaphthalene-1,4-dione (naphthazarin) (2) is used for the first time as a biologically important reagent in the synthesis of gold nanoparticles in water–methanol medium through the chemical reduction of HAuCl4 at room temperature without using any capping agents other than naphthazarin. The ratio of HAuCl4 and naphthazarin played a vital role in controlling the shape and size of gold nanoparticles. Three samples with significant differences in sizes (range of 10–200 nm) have been prepared through increasing the initial naphthazarin/HAuCl4 molar ratio from 50 to 200. The size, distribution, and formation of gold nanoparticles were confirmed by transmission electron microscopy, Fourier transform infrared spectroscopy, and UV–Visible absorption spectroscopic measurements. 2,3-Dihydro-5,8-dihydroxynaphthalene-1,4-dione (naphthazarin) as a green reagent is introduced for the first time in the synthesis of gold nanoparticles in water–methanol medium through chemical reduction of AuCl4 − by a suitable molar ratio of this reagent to HAuCl4 at room temperature without using any capping agents other than naphthazarin. The ratio of HAuCl4 and naphthazarin played a vital role in controlling the shape and size of gold nanoparticles. The size, distribution, and formation of gold nanoparticles were confirmed by transmission electron microscopy and Fourier transform infrared spectroscopy.

Myristic acid capped silver nanoparticles: aqueous phase synthesis and pH-induced optical properties

In this paper we report a facile route for synthesis of myristic acid (C13H27COOH) capped silver nanoparticles under ambient reaction conditions. AgNO3 has been reduced by NaBH4 in the presence of myristic acid in a water-methanol medium at room temperature. pH-induced optical properties of silver nanoparticle were investigated. Particles synthesized were characterized by ultraviolet–visible spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The myristic acid capped silver nanoparticles were found to be 3–7 nm in diameter and exhibit remarkable stability for more than six months. This synthetic route would be advantageous over previous reports of carboxylate stabilized silver nanoparticles using extreme reaction conditions. Noteworthy of the advantages of this synthetic method includes its production of silver nanoparticles in an aqueous medium at room temperature under no inert atmosphere, making the synthesis more environment...

Electrospray ionization mass spectrometric studies on uranyl complex with α‐hydroxyisobutyric acid in water–methanol medium

Hydroxycarboxylic acids are extensively used as chelating agents in the liquid chromatographic separation of actinides and lanthanides. They are also used as model compounds to understand the binding characteristics of humic substances. A systematic study of the speciation of uranyl-α-hyydroxyisobutyric acid (HIBA) in water-methanol is essential, as it is important to understand the various mechanisms responsible for the separation of these species in liquid chromatography. ESI-MS studies were carried out using a tandem quadrupole-time-of-flight mass spectrometer in positive and negative ion mode. The effects of solution composition, solute concentration and supporting electrolyte concentration on the ESI-MS behavior of the uranyl species were studied. Transmission parameters such as the quadrupole ion energy and collision cell energy were optimized for acquiring the spectra of uranyl-HIBA species, ensuring that the spectra reflect the solution equilibrium conditions. The solution composition and concentration of the uranyl salt were found to influence the major uncomplexed uranyl species. Although the ESI parameters did not influence the species distribution of uranyl-HIBA, the transmission parameters did have a significant effect. The overall trend in the complexation reaction between uranyl and HIBA was studied as a function of ligand-to-metal ratio. The species distribution obtained in positive ion mode was similar to that obtained in negative ion mode. The study presents the optimization of the mobile phase conditions and the ESI-MS parameters for the speciation of the uranyl-HIBA system. The methodology was applied to obtaining the distribution of complexed and uncomplexed uranyl species for monitoring the trend in the complexation reaction.

Dual-mode fluorescence switching of photochromic bisthiazolylcoumarin

Three new photochromic coumarins were synthesized. Fluorescence of the open form of 7-hydroxy-3,4-bisthiazolyl-coumarin increased to 1400% by changing the pH only slightly from 6.05 to 7.58. This was subsequently quenched to 1.5% of the maximum intensity at the UV photostationary state in water-methanol media.

Synthesis, spectral characterization and antibacterial studies of palladium(II) complexes of heterocyclic thiones

Reactions of K2[PdCl4] with heterocyclic thiones in molar ratios of 1:2 and 1:4 in water-methanol medium yielded the palladium(II) complexes with the general formula of either [Pd(L)Cl2], [Pd(L)2]Cl2or [Pd(L)4]Cl2where L ═ Imidazolidine-2-thione (Imt), 2-Mercaptopyridine (Mpy), 2-Mercaptopyrimidine (Mpm), 6-Mercaptopurine (6-Mp) and Thionicotinamide (Tna). The complexes were characterized by elemental analysis and spectroscopic (IR,1H and13C NMR) methods. An upfield shift in the >C═S resonance of thiones in13C NMR and downfield shift in N–H or aromatic proton resonances in1H NMR are consistent with the sulfur coordination to palladium(II). The complexes were screened for antibacterial activity, and the results showed that the complexes exhibited moderate activities as compared to that of a standard drug.

Synthesis, spectral characterization and antibacterial studies of palladium(II) complexes of heterocyclic thiones

Reactions of K2[PdCl4] with heterocyclic thiones in molar ratios of 1:2 and 1:4 in water-methanol medium yielded the palladium(II) complexes with the general formula of either [Pd(L)Cl2], [Pd(L)2]Cl2 or [Pd(L)4]Cl2 where L ═ Imidazolidine-2-thione (Imt), 2-Mercaptopyridine (Mpy), 2-Mercaptopyrimidine (Mpm), 6-Mercaptopurine (6-Mp) and Thionicotinamide (Tna). The complexes were characterized by elemental analysis and spectroscopic (IR, 1H and 13C NMR) methods. An upfield shift in the >C═S resonance of thiones in 13C NMR and downfield shift in N–H or aromatic proton resonances in 1H NMR are consistent with the sulfur coordination to palladium(II). The complexes were screened for antibacterial activity, and the results showed that the complexes exhibited moderate activities as compared to that of a standard drug.

Ionic components of the real and chemical Gibbs energy of transport of potassium and chloride ions from water to water-methanol mixtures

With the method of volta-potential differences at 298.15 K the ionic components of the standard real and chemical thermodynamic properties of the resolvation of potassium and chloride ions were determined in mixtures of water and methanol (MeOH). The value of the surface potential at the methanol/gas phase boundary (ΔχMeOH = −0.18 V) is obtained. The characteristics of the solvation of these ions in a water-methanol medium are identified, and a comparison with literature data for other nonaqueous mixtures is carried out.

A new organic compound for the synthesis of gold nanoparticles

2,3,5,6-Tetrakis-(morpholinomethyl)hydroquinone ( 1) is used for the first time in the preparation of gold nanoparticles by the reduction of HAuCl 4 in water–methanol medium without using any capping agent. Compound 1 was prepared by Mannich-type aminomethylation of hydroquinone with morpholine. It is characterized by elemental analysis, FT-IR, UV–Vis and mass spectra and finally by single crystal X-ray diffraction. The ratio of HAuCl 4 and compound 1 played a vital role in controlling the shape and size of gold nanoparticles. The samples were characterized by Transmission Electron Microscopy (TEM), XRD, FT-IR, UV–Vis measurements. With the increasing amount of gold(III) solution with respect to compound 1, two different morphologies such as self-assembled and spherical gold nanoparticles have been observed. The results indicate that the morphology of gold nanoparticles with different sizes can be controlled by changing the concentrations of compound 1 and gold(III) solution.