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Herein we describe 2-chloroimidazo[1,2-a]pyridine-appended Schiff base and chalcone conjugates, exploring their synthetic, spectrophotometric, biological, and computational aspects. UV–visible study revealed that scaffolds VIc and VIIIa exhibit bathochromic and hypsochromic shifts respectively compared to their analogs, due to auxochrome effect. The molecular docking simulations were performed to investigate the binding interactions of motifs with three cancerous target proteins (4HJO, 1M14, and 1M17) and four microbial target proteins. The compound VIIIb exhibited significant anti-lung cancer activity (GI50: 22.3) against the A-459 cell line. Moreover, the synthesized compounds exhibited auspicious antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Klebsiella pneumoniae, with MIC ranging from 64 to 175 µg/mL. Additionally, in-silico target prediction analysis suggested a considerable likelihood (26.7%) of acting on kinases for compounds VIIIa and VIIIc. In-silico toxicity scrutiny anticipated all compounds as non-fatal and less toxic as they belong to toxicity class 4 (300 < LD50 ≤ 2000). Further structural insights into the synthesized compounds were gained through optimized geometries, FMOs, MEP plots, and global reactivity descriptors (µ, ɳ, S, and ω), aiding in understanding their structural features, potential reactivity, and toxicity. Overall, these results highlight the potential of the prepared moieties as hopeful intrants for further development.

Treatment of waste water of industrial enterprises from heavy and toxic metal ions is carried out by traditional reagent method, sorption and membrane technologies. One of the simplest, cheapest, available and effective methods is sorption purification. The peculiarity of the sorption cleaning method is the property of selective absorption from multicomponent solutions and high cleaning efficiency. Treated wastewater can be used in the water supply system of technical circulation. The main of the research work is to study the pH of natural adsorbents in flowing and clean water solutions, particle sizes in suspensions, sedimentation rate and adsorption properties of natural adsorbents for sorption purification of industrial wastewater from toxic metal ions. natural minerals from Almaty region have high sorption properties, that is, they can be used for sorption treatment of industrial wastewater. [ABSTRACT FROM AUTHOR]

Tannins are an important class of secondary metabolites with a wide range of pharmacological effects, due to which they are used in various fields of treatment. In plants of the genus Achillea L., tannins are the dominant class of compounds. This allows the use of plant raw materials and extracts of yarrow for the development of complex herbal and combined formulations of medicines. The search for new sources of natural tannin compounds for pharmaceutical and cosmetic purposes is of significant interest and encourages the improvement of phytochemical research methods of known species of medicinal plants. The aim of the work was to develop a spectrophotometric method for determining the quantitative composition of tannin compounds in terms of gallic acid in the herb of Achillea millefolium L. Materials and methods. The study utilized dried air-dried raw material of yarrow for analysis. The quantitative content of polyphenols in the plant material was determined using a modified UV spectrophotometric method, with calculations based on pyrogallol equivalents. The development of the spectrophotometric technique for determining tannins from the herb of Achillea millefolium L., expressed as gallic acid equivalents, considered the effects of extractant concentration and the degree of plant material grinding. Results. The water extract from the herb of Achillea millefolium L. exhibited a quantitative content of polyphenols, calculated as pyrogallol equivalents, at 2.9781 ± 0.0177 %. It was observed that the particle size of the raw material significantly influenced the yield of active substances. The optimal technological parameters for the developed method involved extracting plant material that was crushed to a size of 0.5–1.0 mm, using 70 % ethanol in a ratio of 1:10, resulting in a yield of 4.08 ± 0.01 %. Conclusions. Based on the obtained results, it is recommended to utilize the developed method, employing gallic acid equivalents, for the quantification of tannins in alcohol-water extracts of yarrow.

[Display omitted] • Spectrophotometric trace determination. • 6-Chloro-3-hydroxy-7-methyl-2-(2′-thienyl)-4-oxo-4H-benzopyran (CHMTB) • Fe(II)- (CHMTB)complex. • DFT Study of Fe(II)-CHMTB complex. • Antibacterial activity study Fe (II)-CHMTB complex. An easy, rapid, sensitive and selective spectrophotometric method which shows maximum absorbance at 433 nm to detect micro amount of Fe(II) with 6-chloro-3-hydroxy-7-methyl-2-(2′-thienyl)-4-oxo-4H benzopyran(CHMTB) has been developed which form a stable dark brownish complex in an acidic environment which is extractable in dichloromethane (DCM). The complex showed molar absorptivity coefficient and sandell'ssensitivity 2.335 x 104 l mol-1and 0.0023 µg cm−2 respectively.The correlation value and detection limit for this method is 0.9998 and 0.0893 µg ml−1 respectively. Various cations and anions/complexing agents had no effect on the detection of divalent iron.The DFT/B3LYP/6-31G(d,p) method is a commonly used computational approach used for studying molecular properties and to calculate energy gaps for complex and ligand which are foundto be 0.0767 eV and 0.1380 eV respectively. Global reactivity descriptors provide valuable information about the reactivity and stability of molecules. Molecular Electrostatic Potential (MEP) analysis is a useful tool for identifying potential sites for nucleophilic or electrophilic attacks on chemical structures. The complex interaction with anti-cancer, antibacterial, and antifungal agents had been thoroughly studied along with the selectivity of the method by its detection in presense of other metal ions. [ABSTRACT FROM AUTHOR]

The solar energy is the mother of all renewable energy resources except nuclear energy. The conversion of solar energy into electrical energy is the interest of research area because electrical energy can be converted into nearly all forms of energy as per requirement. The aim of this paper is to study the spectral behavior of safranine–fructose–sodium lauryl sulphate (SLS) system in alkaline medium, photogalvanic effect of the same system and correlate the relationship between concentration of safranine, fructose, alkali and SLS corresponding to maximum absorbance and electrical output obtained by spectral and photogalvanic study, respectively. To achieve our objective, the absorbance spectra of fixed concentration of safranine solution in presence of different concentration of fructose, NaOH and SLS have been recorded, by varying concentration one of these at a time. It was observed that the presence of alkali and fructose only increased the absorbance value whereas SLS increases both absorbance and λmax value of safranine. This indicates stable safranine–SLS complex (interaction) formation. The photogalvanic effects of the cell containing safranine as photosensitizer, fructose as a reductant with and without SLS as surfactant systems have also been studied using Pt as a working electrode under the influence of artificial light. In presence of SLS, an increase the electrical output of the cells was observed, indicating a strong molecular interaction of safranine-fructose mixed solution with SLS in alkaline medium at laboratory temperature. Hence, the SLS has played a significant role in the enhancement of electrical output of safranine-fructose system. The resultant concentrations of safranine, fructose, alkali and SLS from both studies are strongly supported to each other corresponding maximum absorbance and electrical output value. Therefore, present study may be helpful to understand the reasons for increasing in electrical output of dye-reductant system in presence of surfactant in the photogalvanic cell. [ABSTRACT FROM AUTHOR]

The present work represents the first attempt to apply a polyoxometalates (POMs) type heptamolybdate [Mo7O24]6− as a complexing agent for the removal of toluidine blue (TB) dye by ultrafiltration. Before ultrafiltration study, the interaction between heptamolybdate and dye was investigated using spectrophotometry UV–visible. It was shown that a metachromatic complex dye/POMs type 1:6 was formed with a blue shift from 623 to 550 nm indicating the formation of dye H-aggregates. The ultrafiltration process shows that the addition of heptamolybdate to dye solution greatly improved TB retention from 10 to 97%. The heptamolybdate concentration (0–1 mM), NaCl concentration (0.001–1500 mM), CTAB concentration (0.001–10 mM), pH (2–12) and applied pressure ∆P (2–4 bar) on the dye retention and permeate flux have been investigated. A 25 full factorial design shows that the main influenced factors are CTAB surfactant following by heptamolybdate and salt concentrations. Schematic of the process of TB removal by PAUF method [ABSTRACT FROM AUTHOR]

Motivated by evidence that silver nanoparticles have found numerous technological applications we have explored in this work utilization of polythiocyanatohydroquinone as a new efficient reducing and stabilizing agent for the preparation of such nanoparticles. The formation of silver nanoparticles has been confirmed by the UV-Vis spectroscopy, X-ray powder diffraction and by transmission electron microscopy. The potentiometric and spectroscopy kinetic measurements during the nanoparticles growth are also presented. Thermodynamic activation parameters for the silver nanoparticle formation have been determined from the reaction kinetic studies at variable temperatures. On the ground of observations using these techniques, a mechanism for silver nanoparticle growth has been proposed. The narrow size (20-40 nm) and spherical shape distribution of the fabricated nanoparticles together with the high stability of colloids for sedimentation provide a firm basis for applications of the polythiocyanatohydroquinone polymer as a reducing and stabilizing material for the metal nanoparticles preparation and storage. [ABSTRACT FROM AUTHOR]

Copyright of Lucrari Stiintifice, Universitatea de Stiinte Agricole Si Medicina Veterinara Ion Ionescu de la Brad Iasi, Seria Horticultura is the property of University of Agricultural Sciences and Veterinary Medicine (Editura Ion Ionescu de la Brad) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The kinetics of oxidation of tetracycline hydrate by Cu(Bip)2 2+ in alkaline medium has been investigated spectrophotometrically at 35°C by using Rh(III)-chloride as homogeneous catalyst. The reaction exhibits first order kinetics with respect to lower [Rh(III)] but tends towards zero order at higher [Rh(III)]. The order of reaction shows first-order kinetics with respect to [tetracycline hydrate] and fractional positive order in [Cu(II)] throughout their variations. Nil effects of [OH-] and [bipyridyl] on the rate of oxidation of tetracycline was observed. Almost nil effect of ionic strength as well as dielectric constant of the medium on the rate of oxidation was observed. The reaction was studied at four different temperatures and observed values of rate constants were utilized to calculate various activation parameters such as energy of activation, enthalpy of activation along with entropy of activation. Cu(Bip)2+, tetracycline hydrate as such and RhCl3 (H2O)3 have been postulated as reactive species of Cu(II), tetracycline hydrate and Rh(III)-chloride, respectively, in alkaline medium. With the help of the observed kinetic data with respect to the reactants involved in the reaction and spectrophotometric evidences collected for the formation of reactive complexes, a most probable reaction mechanism has been proposed. [ABSTRACT FROM AUTHOR]

The composition and stability of the complexes of isatin-b-thiosemicarba­zone with Co(II), Ni(II), Cu(II), Zn(II), Pd(II) and Hg(II) have been investigated us­ing spectrophotometric method at 30 °C and constant ionic strength of 0.1 mol dm-3 (KNO3) in 70 % ethanol. Experimental results indicate the formation of MeL and MeL2 complexes for Ni(II) and Co(II), and MeL for Cu(II), Zn(II), Pd(II) and Hg(II) complexes, whose stability constants, bn, have been calculated using a com­puteri­zed iterative method of successive approximation.

The composition and stability of the complexes of isatin-β-thiosemicarbazone with Co(II), Ni(II), Cu(II), Zn(II), Pd(II) and Hg(II) have been investigated using spectrophotometric method at 30°C and constant ionic strength of 0.1 mol dm-3 (KNO3) in 70 % ethanol. Experimental results indicate the formation of MeL and MeL2 complexes for Ni(II) and Co(II), and MeL for Cu(II), Zn(II), Pd(II) and Hg(II) complexes, whose stability constants, βn, have been calculated using a computerized iterative method of successive approximation.

Manganese is of universal occurrence in plant and has been identified as forming metallo-enzymes as superoxide dismutase ( mitochondrial), arginase, pyruvate carboxylase and glycosyl transferase. It also appears to be directly involved in the enzymic machinery of carbohydrates metabolism with a possible link to lipid metabolism. It is also essential for normal bone structure, reproduction and the normal functioning of central nervous system (Bhagi and Chatwal, 2003). Knowing the biological significance and uses of th is essential ultra trace metal, i t was determined spectrophotometerically in the various parts viz; stems, roots, leaves, seeds and flowers of the medicinal plant Sida spinosa Linn. The method used is simple, sensitive, selective and economical which is based on the oxidation of small amounts of manganese present in the drug either by potassium peroxide or ammonium persulphate. The former is usually preferred since it gives a true permanganate colour. Here manganese converts into potassium permanganate in acidic solution and absorbance for the colour thus obtained is compared with the concentration absorbance curve of the various dilutions of the standard solution, for calculating the concentration of manganese in the various parts of the plant understudy (Peach and Tracey, 1939). The concentration of manganese in the various parts of Sida spinosa thus calculated is 2.4 ppm in stems, 1.4 ppm in roots, 1.1 ppm in leaves, 3.7 ppm in seeds and 4.6 ppm in flowers.

Abstract: Kinetics of the oxidation of lactose by Cu(II) complexed with bipyridyl have been investigated at 40°C for the first time spectrophotometrically using Rh(III) chloride as homogeneous catalyst in aqueous alkaline medium in its nano-concentration range. The order of reaction was found to be fractional positive-order, when the concentration of Rh(III) chloride was varied from 0.30×10−9 M to 6.00×10−9 M. The reaction shows fractional positive-order kinetics with respect to [lactose] and [OH−] and zeroth-order kinetics with respect to [Cu(II)]. The reaction also shows slight increase in the rate by decreasing dielectric constant of the medium and remains unaffected by the change in ionic strength of the medium. The reaction was carried out at four different temperatures and observed values of rate constants were utilized to calculate various activation parameters specially the entropy of activation (ΔS #). The species, [RhCl3(H2O)2OH]−, was postulated as the main reactive species of Rh(III) chloride for the oxidation of lactose by Cu(II) in alkaline medium. On the basis of kinetic and equivalence studies together with spectrophotometric information for the formation of a complex, ▪ the most appropriate mechanism for the aforesaid reaction has been proposed. Support to the proposed mechanism was also given by the observed activation parameters and multiple regression analysis. Sodium salts of formic acid, arabinonic acid and lyxonic acid were identified as the main oxidation products of the reaction under investigation. [Copyright &y& Elsevier]

Interaction of p-nitrophenol (NPH) with various surfactants, viz., cetylpyridinium chloride (cationic), sodium dodecylsulphate (anionic) and Triton X-100 (nonionic) are studied spectrophotometrically, in aqueous-micellar medium. The interactions are of electrostatic as well as hydrophobic nature. The strength of interaction is represented in terms of the equilibrium constants and other thermodynamic quantities of formation of the p-nitrophenol-micelle donor-acceptor complexes in addition to a shift in the acid-base equilibrium of NPH. The interaction between NPH and CPC is much stronger that with Triton X-100 whereas the interaction with SDS is very weak. Formation of 1:1 charge transfer (or electron donor-acceptor) complex is evidenced from the results. The interaction of NPH is enthalpy driven with CPC and entropy driven with Triton X-100. [ABSTRACT FROM AUTHOR]

The nutritional value of the products obtained from sweet briar and white sea buckthorn comes from the complexity of their chemical composition. It is remarkable that these fruits contain such a great concentration of ascorbic acid (AA). Our researches on this matter show that the ascorbic content is higher in proportion with the white sea buckthorn than in the sweet briar (sweet briar: 190 mg/100g versus white sea buckthorn: 618mg/100g dry matter). At the same time our research points out the usefulness of the modern extraction methods used to obtain the extracts of sweet briar and white sea buckthorn. The purpose of the paper is also to study spectro-photometrically, on a pure system and from the mentioned extracts, the ascorbic acid stability. Consequently, we studied the dynamics of the ascorbic acid towards different solvents used in extraction: water, trichloroacetic acid (TCA) and acetic acid both in the presence and in the absence of light. On the other hand, the influence of the pH variation on the ascorbic acid stability was taken into account, both towards the pure solution of ascorbic acid and towards the extracts of sweet briar and white sea buckthorn. The spectrophotometric experimental results pointed out the high stability of the ascorbic acid when the extraction reactive was the acetic acid. In this context, the stability of the ascorbic acid from the extracts of sweet briar and white sea buckthorn, towards the acetic acid used as extraction reactive proved to be the best at pH = 2,903 for white sea buckthorn and at pH = 3,264 for sweet briar, in the absence of light. [ABSTRACT FROM AUTHOR]

Abstract: Titanium(IV) chloride reacts with free base meso-tetraarylporphyrin and its ortho, meta and para-substituted derivatives (H2T(X)PP; X: OCH3, CH3 and Cl) for formation of sitting-atop (SAT) complexes, [TiCl4(H2T(X)PP)]. The computer fitting of the variation of the absorbance versus mole ratio by KINFIT program was used for calculation of the formation constants of these complexes in chloroform. Thermodynamic parameters, ΔG°, ΔH°, ΔS°, have been determined and the influence of the temperature and the substituted aryl groups (electronic and steric effects) in the free base porphyrins on the stability of the SAT complexes was studied. [Copyright &y& Elsevier]

The reactions between the drug buspirone (busp) in its base form and iodine amphoteric reagent (n-donor and/or σ-acceptor) and with tetracyanoethylene as a π-acceptor reagent (TCNE) have been studied spectrophotometrically at different reactant concentrations, time intervals, temperatures, and with different solvents and wavelengths, with the aim of selecting the conditions that give the most suitable molar extinction coefficients. This study aims chiefly to throw light on the nature of these reactions and to select the most proper conditions for spectrophotometric application of these reagents to determine this biologically active drug used in treating different diseases. The reaction mechanism involves the formation of busp-I2 outer and inner sphere complexes. The separated busp-I2 solid product obtained was investigated using elemental analyses, FT-IR, thermal analyses (TA) and electron ionization mass spectrometry (EI-MS) and was found to be biologically active. The reaction mechanism of busp-TCNE involves the formation of a charge transfer (CT) complex. The analytical parameters of the proposed spectrophotometric procedures were calculated. These procedures were applied in the analysis of busp in its formulations as a drug used to treat psychiatric illnesses. The values of the Sandell sensitivity, standard deviation (SD), relative standard deviation (RSD) and recovery percentage show the high sensitivity of these procedures. This study also presents a promising new busp-I2 drug derivative that can be used more efficiently for the same purposes as its parent. It gives a clear idea about the possible metabolites and metabolic pathways of busp and its derivative that may occur in vivo. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A spectrophotometric study of the chemical coordination of two nonsteroidal anti-inflammatory drugs (tenoxicam and piroxicam) with Fe(III) has been undertaken in methanol in order to determine the stoichiometry and formation constants of the formed complexes, 1 : 1 and 1 : 2 stoichiometric ratios [Fe(III) : oxicam]. The formation constants determined with the aid of the program SQUAD, at 293 K in methanol, are: Fe(tenox), log β11 = 4.71 ± 0.03; Fe(tenox)2, log β12 = 8.57 ± 0.04; Fe(pirox), log β11 = 5.54 ± 0.09; Fe(pirox)2, log β12 = 9.75 ±0.08. However, the study in acetone gave rise to complexes with completely different stoichiometric ratios with polynuclear species [dimers of Fe(III)]. The formation constants determined with the aid of program SQUAD, at 293 K in acetone, are: Fe2(tenox), log β21 =9.04 ± 0.03; Fe2(tenox)2, log β22 = 14.75 ± 0.06; Fe2(tenox)3, log β23 = 18.45 ± 0.07; Fe2(pirox), log β21 = 9.06 ± 0.30; Fe2(pirox)2, log β22 = 14.77 ± 0.09; Fe2(tenox)3, log β23 = 18.48 ± 0.40. Besides the well-known effect of the solvent on thermodynamic constants, the stoichiometry seems to be strongly driven by the nature of the solvent. [ABSTRACT FROM AUTHOR]

Metal complexes of some divalent metal ions (Co, Ni, Cu, Zn, Hg, and Pd) with isatin- β-thiosemicarbazone (ITS) as the Schiff base have been investigated potentiometrically and spectrophotometrically. The dissociation constants of the ligand and formation constants of the metal complexes, as well as the corresponding thermodynamic functions (Δ G, Δ H and Δ S) have been determined at different temperatures in ethanol—water solution. The full stability constants were also evaluated spectrophotometrically by the Job method. The experimental results indicate that Cu(II), Zn(II), Pd(II), and Hg(II) form one-to-one molecular complexes (ML) with the studied ligand, whereas Co(II) and Ni(II) form both ML and ML2 species. [ABSTRACT FROM AUTHOR]

The stability of curcumin (H3Cur) in aqueous media is improved when the systems in which it is present are at high pH values (higher than 11.7), fitting a model describable by a pseudo-zero order with a rate constant k′ for the disappearance of the Cur3− species of 1.39 (10−9) M min−1. There were three acidity constants measured for the curcumin as follows: pKA3=10.51±0.01 corresponding to the equilibrium HCur2−=Cur3−+H+, a pKA2=9.88±0.02 corresponding to the equilibrium H2Cur−=HCur−2+H+. These pKA values were attributed to the hydrogen of the phenol part of the curcumin, while the pKA1=8.38±0.04 corresponds to the equilibrium H3Cur=H2Cur−+H+ and is attributed the acetylacetone type group. Formation of quinoid structures play an important role in the tautomeric forms of the curcumin in aqueous media, which makes the experimental values differ from the theoretically calculated ones, depending on the conditions adopted in the study. [Copyright &y& Elsevier]