IR Spectroscopic Methods Research Articles

Synthesis and Structural Characterization of the Tetranuclear Iron(Iii) Cluster with Salicylic Acid

A new tetra-homonuclear iron(III) cluster, [Fe4O2(Sal)4(H2O)6]·4DMA·0.75H2O, where Sal= salicylic acid and DMA= N,N-dimethylacetamide consolidated via two µ3-oxo- and four salicylate-bridges was synthesized and characterized by IR spectroscopic method as well as by single crystal X-ray diffraction analysis. The structure of the obtained tetranuclear compound consists of four FeIII atoms in a “butterfly” arrangement. The coordination sphere of each of the two central FeIII atoms is generated by two μ3-oxo-bridging atoms and four oxygen atoms provided by the tridentate-bridging Sal2- ligands, while the coordination polyhedron of another two iron atoms involve six oxygen atoms from three water molecules, two salicylic and one μ3-oxigen atom. The Fe-O distances within Fe-O-Fe bridge are of 2.102(3) Å (for wing-body) and 2.038(3) Å (for body-body).

Mechanochemical Synthesis of Cocrystals of Betulin with Adipic Acid

The cocrystal of betulin with adipic acid was prepared using a liquid-assisted grinding method. The formation of cocrystal was confirmed by powder X-ray diffraction and IR spectroscopy methods. In order to choose a liquid for preparing cocrystal, solvents of different polarity were compared. It was shown that cocrystal of betulin with adipic acid was formed if solvents were used during mechanical treatment, in which the increased solubility of adipic acid was observed

The Structure and Properties of Fe(II) 1,10-Phenanthroline-Thiobarbiturate

The structure of the mononuclear complex [Fe(Bipy)(H2O)2(Htba)2]∙6H2O (I), where Bipy – 2,2’-dipyridine, H2tba – 2-thiobarbituric acid (C4H4N2O2S), was determined by single crystal X-ray diffraction technique (cif-file CCDC No. 1831367). Crystals I are rhombic: a = 17.4697 (7), b = 11.7738 (4), c = 13.4314 (5) Å, V = 2762.6(2) Å3, space group Pnma, Z = 4. Two nitrogen atoms of the Bipy molecule and two water molecules are located in the equatorial plane of the octahedral complex, and two S-coordinated Htba− ions the axial positions are occupied. The structure is stabilized by N−H∙∙∙O, O−H∙∙∙O, С−H∙∙∙O, C−H∙∙∙S intermolecular hydrogen bonds and π–π interaction between Bipy and Htba−. The compound is characterized by the methods of powder X-ray diffraction, thermal analysis, and IR spectroscopy

Electrosynthesis of Silver Nanocomposites Based on N-Vinylimidazole and N-Vinylpyrrolidone

Silver nanocomposites and nanocomposite coatings based on copolymers of N-vinylimidazole and N-vinylpyrrolidone are synthesized in water and water-ethanol media on electrodes of pure iron and steel by an electrochemical technique. The composition and structure of nanocomposites is confirmed by the methods of electron and IR spectroscopy, X-ray diffraction analysis, transmission electron microscopy, thermogravimetry, etc. The solubility of nanocomposites is shown to depend on the concentration of silver particles in the (co)polymer matrix. The thermal decomposition of nanocomposites proceeds in stages.

Study of Biologically Active Solid-phase Systems Based on Halogen-substituted Nitrobenzofuroxans by the IR Spectroscopy Method

Introduction. Biologically active compounds 4,6-dinitro-5,7-dichlorobenzofuroxan (4,6-DNDHBFO) and 5-nitro-4,6-dichlorobenzofuroxan (5-NDHBFO) effectively in-hibit ultra-resistant microorganisms: Staphylococcus aureus, pathogenic fungi – Aspergillius niger, Coniophora cerebella, Candida albicanas and other microor-ganisms. Mixed systems based on 4,6-DNDHBFO and 5-NDHBFO exhibit high potentiated synergistic activity against Aspergillius niger. Currently, there are no full-fledged studies about the mechanism of synergism of 5-NDHBFO and 4,6-DNDHBFO in a solidphase system. The results of the study of solid-phase sys-tems 5-NDHBFO – 4,6-DNDHBFO by IR spectroscopy will make it possible to establish the nature of the interaction between the components of the binary mix-ture.Aim. Experimental study of the intermolecular interaction of 5-NDHBFO with 4,6-DNDHBFO by the IR spectroscopy method.Materials and methods. The intermolecular interaction of 5-NDHBFO with 4,6-DNDHBFO at different ratios in a solid-phase system was studied by the IR spectroscopy method.Results and discussion. Based on the results of the study, the physico-chemical interaction of 5-NDHBPO with 4,6-DNDHBFO in solid-phase systems was revealed. Shifts and changes in the intensities of the characteristic frequencies of functional groups involved in the formation of intermolecular bonds between 5-NDHBPO and 4,6-DNDHBPO were revealed.Conclusion. The nature of the interaction between 4,6-DNDHBFO and 5-NDHBFO in the solid-phase system was established, leading to the appearance of a synergy effect. The interaction of 5-NDHBFO with 4,6-DNDHBFO in a bi-nary system is due to the formation of an intermolecular hydrogen bond. The in-teraction involves the proton of the 5-NDHBFO molecule, the oxygen of the fu-roxan ring of 4,6-DNDHBFO, as well as the halogen atom of 4,6-DNDHBFO at an equimolar ratio of the components of the solid-phase system.

Physical and Chemical Properties and Quality Control Methods of Hyaluronic Acid (Review)

Introduction. This review describes the physicochemical properties that determine the use of hyaluronic acid in ophthalmology. We have studied methods for determining hyaluronic acid using various analytical methods.Text. Hyaluronic acid is a high molecular weight glycosaminoglycan that consists of repeating disaccharides of N-acetylglucosamine and D-glucuronic acid. Carboxyl, hydroxyl and acetoamide groups give hydrophilic properties to the molecule of this anionic heteropolysaccharide. Depending on how the hyaluronic acid is obtained, its molecular weight varies over a wide range. Researchers developed methods for controlling hyaluronic acid, which include the turbidimetric titration method, the method of high-performance capillary electrophoresis and high-performance liquid chromatography and IR spectroscopic method.Conclusion. Due to its properties, hyaluronic acid is widely used as an active ingredient in pharmaceutical preparations. Today, there are a number of methods for the determination of hyaluronic acid, including the method of turbidimetric titration, the method of capillary electrophoresis. High performance liquid chromatography (HPLC) and IR spectroscopy methods are presented in the Japanese Pharmacopoeia and the European Pharmacopoeia. These techniques are widely used due to their high reproducibility, accuracy, and relative simplicity.

Crystal Structure, Spectroscopic and DFT Computational Studies of N-(4-Fluorophenyl)-1-(5-Nitrothiophen-2-yl)methanimine

A novel Schiff base compound was synthesized and characterized by IR spectroscopy and X-ray diffraction method. The compound crystallizes in monoclinic space group P21/c with Z = 4 in the unit cell. The ring systems are perfectly planar but the whole molecule is not planar. The dihedral angle between the thiophene and phenyl rings is 38.7(3)°. In the crystal, intermolecular C–H⋅⋅⋅O interactions link the molecules into a C(7) chain along the [20 $$\bar {1}$$ ] direction. The crystal packing is also stabilized by N–O⋅⋅⋅π interaction. The molecular structure and vibrational frequencies of the title compound were calculated using the DFT/B3LYP method with the 6-311++G(d,p) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structure, and the theoretical vibrational frequencies show good agreement with experimental results.

New 3,4-seco-diterpene and coumarin derivative from the leaves of Trigonostemon flavidus Gagnep

Two new compounds named trigoflavidus A (1) and trigoflavidus B (2), and eight known compounds, trigoflavidone (3), heterophypene (4), howpene C (5), 3,4-seco-sonderianol (6), trigonochinene C (7), fraxidin (8), isofraxidin (9), and isofraxetin (10) were isolated from the leaves of Trigonostemon flavidus Gagnep. by various chromatographic methods. Their chemical structures were elucidated via UV, IR, HR-ESI-MS and NMR spectroscopic methods and divided into two groups including six 3,4-seco-diterpenes (1, 3-7) and four coumarins (2, 8-10). Absolute configurations at stereocenters of compound 1 were confirmed by comparison of its CD spectra with those of the TD-DFT calculations. At a concentration of 30 µM, compounds 1–10 exhibited weak cytotoxic activity toward LU1, HepG2, MCF7, and SKMel2 human cell lines (cell viability all over 50%).

Anti-oxidant and Antiproliferative Activities of Mongolian Medicinal Plant Extracts and Structure Isolation of Gnetin-H Compound.

Reactive oxygen species are involved in the etiology and progress of many kinds of diseases such as cancer, cardiovascular diseases, inflammatory and neurodegenerative disorders. Epidemiological studies reported that fruits, vegetables, and wines containing a high percentage of phenolics and flavonoids showed a positive impact in treating inflammatory diseases, reducing cancer risk, and increasing life expectancy. Some Mongolian medicinal plants were studied for their antioxidant activity and anticancer effects. Selected Mongolian medicinal plant extracts were examined for their antioxidant activity by the DPPH-radical scavenging assay, the content of phenolics and flavonoids by Folin-Ciocalteu and the Dowd method, respectively, and anti-cancer activities in human hepatoma cell line HepG2 cells by MTT assay. Methanol extract from Hippophae rhamnoides L. leaf and ethanol extract from Artemisia macrocephala Jacq. ex Bess. showed the highest efficiency to scavenge free radicals. Ethanol extracts from Hippophae rhamnoides L. grain and Paeonio anomala L. leaf showed the highest total phenolics content, whereas Hippophae rhamnoides L. fruit methanol extract and ethanol extract from Caragana leucophloea pojark. mentioned the highest flavonoids content. The Artemisia macrocephala Jacq. ex Bess seed wallet and Paeonia anomala L. seed wallet showed the most potent antiproliferative effects against human liver cancer HepG2 cell line. Gnetin-H compound was isolated from the Paeonio anomala L. seed wallet extract, and its molecular structure was determined by 1H and 13C NMR spectrum and IR spectroscopy methods. The screening study on anti-oxidative effects of 21 extracts from 15 Mongolian medicinal plants showed anti-oxidative activities and was rich in phenolics and flavonoids. Among these, methanol extract of the Hippophae rhamnoides L. leaf showed a better anti-oxidative effect than the ethanol extract. Artemisia macrocephala Jacq. ex Bess and Paeonia anomala L. seed wallet mentioned the best anti-cancer effects. Gnetin-H, methyl gallate, ethylgallate were the major components in the extract from the Paeonio anomala L. seed wallet. Finally, the molecular structure of gnetin-H was determined by NMR and IR spectroscopy. Further investigation, especially in vivo antioxidant activity, is needed to justify the use of a natural source of antioxidants to prevent the progression of diseases such as cancer.

СИНТЕЗ ГАЛОГЕНОВАНОЇ РОСЛИННОЇ ОЛІЇ ДЛЯ ОДЕРЖАННЯ ПОЛІМЕРНИХ МАТЕРІАЛІВ

In the work presents to test of the possibility of using halogenated vegetable oil to obtain polymeric materials. The result of the conducted research the development of the methodology of halogenation of sunflower oil presented and confirmed of its structure by the method of IR spectroscopy. The obtained halogenated oil was used to reactions of interact with compounds of different functionality. Synthesized materials was using for obtain polymer composite materials by thermopolymerization with vinyl monomers.

Synthesis and Hemozoin Inhibitor of Side-Chain Modified Copper-Chloroquine Derivatives

This study uses copper (I) as a transition metal to improve the activity of 4-aminoquinoline as an antimalarial agent. This chloroquine derivative was synthesised and tested for in vitro antimalarial activity using a simple colourimetric method compared to the conventional purification method to measure hemozoin formation. This compound has been characterised by the combination of NMR and IR spectroscopic methods. Copper-chloroquine (Cu-CQp) might strongly exhibit antimalarial activity after showing significant inhibition of hemozoin formation compared to commercial chloroquine (CQ). This is possibly due to its lipophilicity, which enhances cell permeation. The highest activity was shown by the Cu-CQp complex in comparison to that of commercial CQ. Cu-CQp complex and CQ were used in a range of concentrations from 10–50 µM.

Integral Role of the NiS Electrode/Electrolyte Interface in the Redox Reaction with Lithium

Electrochemically synthesized thin-layer NiS electrodes were studied in lithium perchlorate dissolved in 1.3-dioxolane or in a mixture of 1.3-dioxolane and tetrahydrofuran. In the 1.3-dioxolane 1 M LiClO4 electrolyte, the irreversible capacity was reduced by 20% сompared to the initial capacity. However, the stability of the electrochemical characteristics of NiS electrodes in redox reactions with lithium is unsatisfactory. Much better results of charge–discharge cycling of NiS electrodes were obtained in the electrolyte solutions of 1.3-dioxolane, tetrahydrofuran, and 1 M LiClO4 demonstrating a stable reversible capacity of 400–450 mAh/g during 50–75 cycles. Using the methods of electron microscopy and IR spectroscopy with Fourier transform, it was established that the reason for the discharge capacity fading of NiS electrodes was associated with the formation of a surface film, which reduces the adhesion and cohesion of NiS particles. This, in turn, leads to a loss in the mechanical strength of NiS electrodes.

STRUCTURE CHARACTERIZATION OF CALCIUM DEFICIENT ELEMENT-SUBSTITUTED HYDROXYAPATITE WITH CONSTANT DOPANT RATIO OF DIFFERENT ELEMENTS

The element-substituted calcium Deficient hydroxyapatite samples were synthesized using liquid-phase precipitation method. Different element ions (Mg+2, Zn+2, and Cu+2) were added at constant ratio (5% wt.). The phase composition of the element-substituted calcium hydroxyapatite samples was investigated by using X-ray diffraction. A comparison with known characteristics of the synthetic ion-substituted forms of hydroxyapatite was conducted. It was determined, that the investigated materials are single-phase solid solutions of the element-substituted hydroxyapatite. By the methods of IR spectroscopy and Raman scattering (RS) it was discovered the dependence of incorporation of the carbonate anion that occupies a positions of phosphorus-oxygen groups in the hydroxyapatite structure as a result of embedding element ions (Zn+2, Cu+2, Mg+2) in the crystal lattice. Besides, It was determined, that the ratio of the intensities for the C03 group mode to the P04 groups mode depended on the nature of the element atom, which replace the calcium in the lattice of HAP, and reduced by substituting the calcium atoms by the atoms of Zn, Cu, and Mg from 0.15 to 0.06. Modeling of the vibration modes of Raman spectroscopy showed that incorporation of carbon atoms to the hydroxyapatite structure correlate with the Zn, Cu and Mg atomic radius, charge, and activity

Determining the content of macronutrients in berry sauces using a method of IR-spectroscopy

This paper has substantiated the possibility of using an IR spectroscopy method to study patterns in the chemical composition of wild and cultivated raw materials with the addition of algae as iodine-containing supplements. It has been found that the IR spectra of sauces based on the mashed blueberry and sea buckthorn or cranberry with or without algae demonstrate a set of absorption bands attributed to the respective types of oscillations. The valence fluctuations in the hydroxyl groups in the molecules of organic acids, carbohydrates, flavonoids are observed at 3,365 cm -1 to 3,400 cm -1 ν(ОН). The bands of valence and deformation fluctuations of the ‒CH double bond of polyunsaturated fatty acids manifest themselves in the range of 3,005 cm -1 and722 cm -1 . The bands of 2,925 cm -1 , 2,855 cm -1 belong to the asymmetric and symmetric valence oscillations of the n(С–Н) carbon skeleton in -CH 2 -. The presence of the carboxylic, amino-, and fatty acids is indicated by the following absorption bands: 1,746 cm -1 ‒ ν (C=O) valence fluctuations in the protonated carboxyl group ‒COOH; 1,545 cm –1 ‒ ν as (C=O; 1,415 cm –1 ‒ ν s (C=O) ‒ the asymmetric and symmetric valence fluctuations of the СОО - groups; and 1,240 cm –1 ‒ the valence fluctuations of ν(C‒O). The presence of flavonoids is confirmed by the presence of bands at 1,380 cm -1 and 1,050 cm -1 ‒ the deformation δ(O‒H) and symmetrical fluctuations of O‒H groups. The fluctuations of pyranose cycles of pectins are manifested in the range of 1,163 cm – 1 . It is noted that the composition of berry raw materials and sauces include polyunsaturated fatty acids, anthocyanins, flavonoids, organic acids, and pectin substances. An analysis of the IR spectra of berry sauce samples with the addition of algae has shown that the use of these additives in sauce technologies ensures a significant increase in the content of the physiological and functional ingredients and improves the hydrophobic properties of the raw materials

Synthesis of some new benzoxazole derivatives and investigation of their anticancer activities.

Phortress is an anticancer prodrug, which has active metabolite (5F-203) being potent agonist of the aryl hydrocarbon receptor (AhR). The 5F-203 switches on cytochrome P450 CYP1A1 gene expression and thus exhibits anticancer activity. In this study, it is aimed to obtain new phortress analogues by bioisosteric replacement of benzothiazole core in the structure to benzoxazole ring system. Synthesis of compounds (3a-3p) were performed according to literature methods. Their structures were elucidated by IR, 1H NMR, 13C NMR, 2D-NMR and HRMS spectroscopic methods. Cytotoxicity (MTT), inhibition of DNA synthesis and flow cytometric analysis assays were applied to determine anticancer activity of the compounds on colon (HT-29), breast (MCF7), lung (A549), liver (HepG2) and brain (C6) carcinoma cell types. When compared reference agent doxorubicin, compounds 3m and 3n displayed very attractive anticancer effect against carcinogenic cell lines. Due to structural similarity to phortress, biotransformation studies for 3m and 3n were examined by LCMS-IT-TOF system and probable metabolites of these compounds were determined. Induction potential of these compounds on CYP1A1/2 enzymes was also investigated to clarify possible mechanism of action. Interaction modes between CYP1A1 enzyme and compound 3n or its some metabolites were investigated by docking studies. In conclusion, findings of these study indicate that compounds 3m and 3n possess significant anticancer activity, probably with the same mechanism of action to Phortress.

Six transition metal–organic materials with the ditopic 4,4′-diaminodiphenylmethane ligand: Synthesis, structure characterization and luminescent properties

Six coordination compounds based on 4,4′-diaminodiphenylmethane (dadpm) and different salts (acetates, nitrates and perchlorates) of four (Ni, Co, Zn, Cd) transition metals have been prepared and characterized by IR spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction methods. The crystalline solids include four monomers: [Co(dadpm)2(CH3COO)2(H2O)2] (1), [Cd(dadpm)2(CH3COO)2(H2O)2] (2), [Zn(dadpm)4(H2O)2](NO3)2(H2O)2 (3), [Ni(dadpm)3(dmf)(H2O)2](ClO4)2(dadpm)(H2O) (4), and two one-dimensional coordination polymers: {[Cd(dadpm)2(H2O)(ClO4)](ClO4)}n (5) and {[Cd(dadpm)4](ClO4)2}n (6). The transition metals used in this study accommodate two, three, four and six dadpm ligands in the coordination cores. The luminescence properties for six coordination compounds are reported.

Features of Structure and Properties of pнeмa-gr-pvp Block Copolymers, Obtained in the Presence of Fe2.

This paper presents the research results of the copolymer structure and properties of 2-hydroxyethylmethacrylate (HEMA) with polyvinylpyrrolidone (PVP) and their hydrogels, obtained by block polymerization in the presence of iron sulfate (II). By the methods of chemical analysis, IR spectroscopy, Thermogravimetric (TG) and Differential Thermal Analysis (DTA), the course of grafted copolymerization of HEMA on PVP with the formation of a cross-linked copolymer was confirmed. The results received by scanning electron microscopy showed that due to the copolymerization of HEMA with PVP, macroporous hydrogels with a pore size of 10–30 μm were obtained. The peculiarities of the structure formation of the obtained copolymers depending on the initial composition formulation were established and their structural parameters were investigated: PVP grafting efficiency, PVP content in copolymer, molecular weight of internodal fragment of polymer network, crosslinking degree, and crosslinking density. The interrelation of sorption–diffusion, physical–mechanical and thermophysical properties along with the structure of the obtained materials was proved. It was shown that with the increasing PVP content in the original composition, the efficiency of its grafting and crosslinking density of the polymer network decreased, but the surface hardness, heat resistance, sorption capacity of copolymers in the dry state, as well as ion permeability and elasticity in the swollen state increased, while their tensile strength deteriorated. It is proved that by changing the original composition formulation it is possible to change the structure and hence the properties of the copolymers in the desired direction.

Synthesis of Aromatic Polyethersulfones

Modified aromatic polyethersulfones containing dichloroethylene and arylate groups in the main chain were modified . The kinetics of the synthesis of polyethersulfones by the method of acceptor-catalytic polycondensation was studied. By the methods of IR spectroscopy, elemental, X-ray phase analysis, the formation of polymers of a given structure is proved. It is shown that the property of the obtained polymers depends on the ratio of the starting monomers.

Synthesis and Biological Activity of 2-Aryl-4-hydroxy-4-methyl-6-oxocyclohexane-1,3-dicarboxamides

The reaction of unsubstituted acetoacetamide with aromatic aldehydes in ethanol in the presence of piperidine gave 2-aryl-4-hydroxy-4-methyl-6-oxocyclohexane-1,3-dicarboxamides and 4-aryl-5-acetyl-2-hydroxy-2-methyl-6-oxopiperidine-3-carboxamides. Structures of the obtained compounds were proved using IR, 1H and 13C NMR spectroscopy methods. The synthesized compounds were tested for antimicrobial and analgesic activities.

Метод ИК спектроскопии в исследовании облученной мышечной ткани свинины и ее составляющих

Метод ИК спектроскопии в исследовании облученной мышечной ткани свинины и ее составляющих