IR Methods Research Articles

Novel Imine Complexes Incorporating ZrO(II), VO(II), and Pd(II) Cations: Synthesis, DFT Calculation, Molecular Docking, Antimicrobial, and Antitumor Activity

ABSTRACTNovel imine complexes of ZrO(II), VO(II), and Pd(II) have been synthesized and described using IR, TGA, UV/Vis, and 1HNMR methods, along with powder X‐ray diffraction (XRD), elemental (CHN) analysis, mass spectrometry, molar conductance, and magnetic susceptibility measurements. Conductivity measurements indicate that none of the complexes function as electrolytes. Magnetic susceptibility data confirm the paramagnetism of the VO(II) complex, while ZrO(II) and Pd(II) complexes exhibit diamagnetic properties. Various analyses suggest that divalent cations favor a 1:1 metal‐to‐ligand ratio. Biological studies demonstrated that all complexes possess significant antimicrobial activity against a range of bacterial and fungal strains. We also observed that the antimicrobial potency of the metal complexes follows the order: ZrO(II) > Pd(II) > VO(II) > H2A, with the ZrO(II) complex showing the highest inhibition zone (28 mm) against Gram‐negative bacteria. The antifungal activity against Aspergillus flavus increases in the order VO(II) > ZrO(II) > Pd(II) > H2A. Additionally, the complexes exhibit high cytotoxicity against carcinoma cell lines, including the HepG‐2, when compared with the clinically proven vinblastine. Density functional theory (DFT) calculations were performed to elucidate the equilibrium geometry of the imine ligand and its complexes at the B3LYP level of theory, using the Gaussian 09 program with 6‐311G++(dp) basis set for C, H, O, N, and Cl atoms, and lanl2dz for Pd, V, and Zr atoms. Finally, docking studies revealed potential binding modes at the active sites of bacterial and fungal receptors.

The first type of binuclear copper complex with terminal sulfide: synthesis, structural characterization, and cytotoxicity evaluation

A novel copper complex of [CuII (μ2–S)(terminal-S)(2-acetylpyrdine oxime)2 (1) is synthesized and characterized by X-ray single-crystal diffraction. The free ligand of 2-acetylpyrdine oxime is an unexpected product obtained from a condensation reaction of p-aminobenzene sulfonamide and 2-acetylpyridine and is characterized by IR, 1HNMR, and 13CNMR spectroscopic methods. X-ray crystallography showed strictly planar bridged μ2- Cu2(S)2 core, and each copper(II) center exhibits distorted square pyramidal coordination geometry. The cytotoxicity of the complex was tested in vitro against esophageal cancer (SKGT-4) cell lines by metabolic tests, using 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide as a reagent. Complex 1 showed a remarkable inhibition response in SKGT-4 cell lines.

Synthesis of 1-aminoalkyl-5,6-diaryl-2-oxopyrrolo[3,4-<i>c</i>]pyrazoles

The reaction of substituted 1-aminoalkyl-3-hydroxy-3-pyrrolin-2-ones with hydrazine hydrate in boiling glacial acetic acid leads to the formation of 1-aminoalkyl-5,6-diaryl-2-oxopyrrolo[3,4-c]pyrazoles. The structure of the obtained compounds was confirmed by IR, 13C NMR and 1H NMR spectroscopy methods.

Molecular insights into genistein-NSAID hybrids—synthesis, characterisation and DFT study

AbstractGenistein (GEN) is one of the pharmaceutically valuable phenolic compounds, which belongs to the isoflavone group of flavonoids and is a natural phytohormone found mainly in soybeans and red clover. It affects estrogen receptors, functioning as a selective estrogen receptor modulator (SERM) with anti-inflammatory and antioxidant activity. The presence of reactive phenolic groups in genistein provides an opportunity to expand its structure by introducing components responsible for anti-inflammatory properties. Such an innovative combination of a compound with anticancer and antioxidant potential with an anti-inflammatory compound (NSAID) may lead to interesting new derivatives with dual mechanisms of biological action. The synthesis and characterisation of genistein-NSAID hybrid compounds (ibuprofen, ketoprofen, naproxen, flurbiprofen) was conducted, together with a comprehensive structural and quantum chemistry DFT (density functional theory) computational analysis allowing the description of 1H-NMR and 13C-NMR spectroscopic properties of the starting compounds and the resulting hybrids. The study resulted in the formation of seven hybrid GEN-NSAID derivatives. In the case of ibuprofen, ketoprofen and flurbiprofen, a mixture of isomeric hybrid GEN-4’-NSAID and GEN-7-NSAID derivatives was obtained, whereas, for naproxen, only GEN-4’-NSAID was formed. The structural characteristics of the resulting compounds were determined using MS, IR, 1H-NMR and 13C-NMR spectroscopic methods. The most accurate DFT computational methods for predicting 1H-NMR and 13C-NMR spectra were also established with statistical parameters to assess their accuracy.

Synthesis of nitrogen-doped carbon quantum dots (N-CQDs) using microwaveassisted hydrothermal method for tyramine determination

In this study, we develop a rapid, efficient, low-cost and environmentally friendly method to synthesize nitrogen-doped carbon quantum dots (N-CQDs). With simple input materials as citric acid and urea, N-CQDs were sucessfully synthesized in only 5 minutes using a domestic microwave oven. Characterisation results using TEM, UV–VIS, IR and fluorescence methods have demonstrated the successful doping of N into CQDs. The obtained N-CQDs material has a particle size of less than 10 nm, and the fluorescence quantum efficiency (36.6%), which is significantly higher than that of undoped CQDs (17.2%). The N-CQDs material also exhibits an on-off fluorescence effect in the presence of Au nanoparticles (AuNPs) and in the presence of tyramine, a biological amine commonly found in food products such as cheese, fish sauce, soy sauce, kimchi, etc. The fluorescence recovery of N-CQDs/AuNPs is linearly proportional to the tyramine concentration in the range from 0.02 ppm to 1 ppm, showing the possibility of using this material to detect and quantify tyramine in food samples.

New Pyrazole/Pyrimidine-Based Scaffolds as Inhibitors of Heat Shock Protein 90 Endowed with Apoptotic Anti-Breast Cancer Activity.

Background/Objectives: Supported by a comparative study between conventional, grinding, and microwave techniques, a mild and versatile method based on the [1 + 3] cycloaddition of 2-((3-nitrophenyl)diazenyl)malononitrile to tether pyrazole and pyrimidine derivatives in good yields was used. Methods: The newly synthesized compounds were analyzed with IR, 13C NMR, 1H NMR, mass, and elemental analysis methods. The products show interesting precursors for their antiproliferative anti-breast cancer activity. Results: Pyrimidine-containing scaffold compounds 9 and 10 were the most active, achieving IC50 = 26.07 and 4.72 µM against the breast cancer MCF-7 cell line, and 10.64 and 7.64 µM against breast cancer MDA-MB231-tested cell lines, respectively. Also, compounds 9 and 10 showed a remarkable inhibitory activity against the Hsp90 protein with IC50 values of 2.44 and 7.30 µM, respectively, in comparison to the reference novobiocin (IC50 = 1.14 µM). Moreover, there were possible apoptosis and cell cycle arrest in the G1 phase for both tested compounds (supported by CD1, caspase-3,8, BAX, and Bcl-2 studies). Also, the binding interactions of compound 9 were confirmed through molecular docking, and simulation studies displayed a complete overlay into the Hsp90 protein pocket. Conclusions: Compounds 9 and 10 may have apoptotic antiproliferative action as Hsp90 inhibitors.

Hydrocarbons in waters and bottom sediments of the coastal areas of the Caucasian sector of the Black Sea (2021–2023)

The current level of aliphatic and polycyclic aromatic hydrocarbons was determined in suspended particulate matter of waters (mainly in surface waters) and in upper layer of bottom sediments of coastal areas in the Caucasian sector of the Black Sea of the Russian Federation (September 2021, May and September 2022, March 2023). IR method was used to determine the aliphatic hydrocarbons, and the method of high performance liquid chromatography was employed for PAHs. The average concentration of aliphatic hydrocarbons was ≈20 μg/L and for polycyclic aromatic hydrocarbons ≈130 ng/L in suspended particulate matter in open surface waters of Gelendzhik and Golubaya bays. Their content naturally increased as they approached the coast. Despite the decrease in hydrocarbon concentrations in surface waters in recent years, the Kerch Strait and Novorossiysk remain the most polluted areas as before. Higher concentrations in the waters of the Taman Peninsula may be caused by the seepage of hydrocarbons from the sedimentary layer. Hydrocarbons are accumulated in bottom sediments, that leads to their rising portion in total organic carbon (e.g., aliphatic hydrocarbons up to 14.2 % in the Tuapse region and 13.1 % in the Novorossiysk region). Along with contamination from anthropogenic sources, natural processes also affect the hydrocarbon levels such as high biological productivity of the area and fluid flows from the sediment layer.

RBP-DIP: Residual back projection with deep image prior for ill-posed CT reconstruction

The success of deep image prior (DIP) in a number of image processing tasks has motivated their application in image reconstruction problems in computed tomography (CT). In this paper, we introduce a residual back projection technique (RBP) that improves the performance of deep image prior framework in iterative CT reconstruction, especially when the reconstruction problem is highly ill-posed. The RBP-DIP framework uses an untrained U-net in conjunction with a novel residual back projection connection to minimize the objective function while improving reconstruction accuracy. In each iteration, the weights of the untrained U-net are optimized, and the output of the U-net in the current iteration is used to update the input of the U-net in the next iteration through the proposed RBP connection. The introduction of the RBP connection strengthens the regularization effects of the DIP framework in the context of iterative CT reconstruction leading to improvements in accuracy. Our experiments demonstrate that the RBP-DIP framework offers improvements over other state-of-the-art conventional IR methods, as well as pre-trained and untrained models with similar network structures under multiple conditions. These improvements are particularly significant in the few-view and limited-angle CT reconstructions, where the corresponding inverse problems are highly ill-posed and the training data is limited. Furthermore, RBP-DIP has the potential for further improvement. Most existing IR algorithms, pre-trained models, and enhancements applicable to the original DIP algorithm can also be integrated into the RBP-DIP framework.

Re-examination of the Claimed Isolation of Stable Noncyclic 1,2-Disulfoxides.

Re-examination of the claimed isolation and X-ray characterization of di-p-tolyl and dimesityl 1,2-disulfoxides from thermolysis of the corresponding aryl sulfinimines and thiosulfinates showed that the isolated disulfide dioxides are instead the well-known isomeric thiosulfonates, as confirmed by XAS, DART-MS, X-ray, IR and NMR methods. Concerns with the original X-ray structures are addressed. Our results agree with the DFT prediction of very weak diaryl 1,2-disulfoxide S-S bond dissociation enthalpies. For now, room-temperature-stable noncyclic 1,2-disulfoxides remain unknown.

Synthesis and characterization of new hexahydroquinoline derivatives and evaluation of their cytotoxicity, intracellular ROS production, and inhibitory effects on inflammatory mediators.

Inflammation is a response to injury and infection in an organism. It can be categorized as acute or chronic. Chronic inflammation is the underlying cause of many diseases such as Alzheimer disease, diabetes, rheumatoid arthritis, atherosclerosis, and cardiovascular diseases. Recent studies have proven the antiinflammatory properties of 1,4-dihydropyridines (1,4-DHPs) and their derivatives, which have many biological activities including the blocking of calcium channels. In this study, 15 compounds that are condensed derivatives of 1,4-DHPs, with the general structure of hexahydroquinoline-3-carboxylate, were synthesized. These compounds, expected to show inhibitory activity against inflammatory mediators, were obtained by the reaction of 4-(difluoromethoxy)benzaldehyde, substituted/nonsubstituted 1,3-cyclohexanedione derivatives, and appropriate alkyl acetoacetate compounds in the presence of ammonium acetate as a nitrogen source according to the Hantzsch synthesis method. The structures of the synthesized compounds were elucidated by IR, 1H NMR, 13C NMR, and HRMS methods. The cytotoxic properties of the compounds were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method in the 3T3 cell line. Among the 15 compounds, the three compounds with the lowest levels of cytotoxic effects were selected for further experiments. Inflammation was induced by lipoxygenase and the effects of the selected compounds on the levels of reactive oxygen species, cytokines, and complement C3 and C9 regulatory proteins were investigated. It was found that the three selected compounds decreased the levels of transforming growth factor-beta 1 (TGF-β1). Among these compounds, compound 3e provided the most significant decrease in this cytokine. Moreover, 3e increased both C3 and C9 levels. Molecular modeling studies also showed that 3e had better affinity for TGF-β1. When the binding modes of these compounds in the active site of TGF-β1 were analyzed, it was found that compound 3e had hydrophobic interactions with amino acids Leu142, Tyr84, and Ile13; halogen bond interactions with Asp92; and hydrogen bond interactions with Ser89, Gly88, and Gly14 in the active binding site. Further in vitro and in vivo studies are needed to show the possible mechanism of action of compound 3e.

Tetrafluorosubstituted titanyl phthalocyanines: Structure of single crystals and phase transition in thin films

In this work, tetrafluorinated titanyl phthalocyanines with F-substituents in both peripheral (TiOPcF4-p) and non-peripheral (TiOPcF4-np) positions were synthesized and characterized by the methods of elemental analysis, IR and electronic absorption spectroscopies. The influence of the position of F-substituents on the structure of TiOPcF4-p and TiOPcF4-np single crystals and thin films grown by vacuum sublimation was studied. TiOPcF4-p crystallizes in the I4/m space group and its molecules form uniform stacks along the tetragonal axis. Introduction of F-substituents to non-peripheral positions leads to the change of the crystal structure: TiOPcF4-np crystallizes in the P-1 space group and its molecules are packed into 2D layers. Both phthalocyanines form oriented polycrystalline films when deposited by thermal sublimation in vacuum, but their phase composition is different from that of single crystals. The effect of post-deposition annealing of TiOPcF4-p and TiOPcF4-np films on their phase composition, morphology, optical absorption and Raman spectra, as well as conductivity was revealed. It was shown that a phase transition, which led to the appearance of an additional band in the near-IR region in the optical absorption spectrum, was observed in TiOPcF4-p films when heated, whereas no phase transition was observed in TiOPcF4-np films.

Характеристики эласмоидной чешуи рыб и ее фракций, по данным ИК-Фурье-спектроскопии

Elasmoid scales of pike-perch (Sander lucioperca), white amur (Ctenopharyngodon idella), carp (Cyprinus carpio), freshwater bream (Abramis brama) and crucian carp (Carassius carassius) were processed without hydrolysis by “dry” method in order to study the characteristics of the obtained finished product, which determine its further use as additives for food and other purposes. The essence of the method consisted in washing the scales, its subsequent drying, grinding and separation, with obtaining two fractions enriched with both organic (cotton-like product) and inorganic (powder) components. FT-IR spectroscopy was used to characterize the scale samples and their enriched fractions. Characteristic bands known for collagen, in particular for Amide I, Amide II, Amide III, Amide A, were observed in the IR spectra of all the samples studied. The bands (inorganic part) at ~1022 cm–1 and at ~599 cm–1 indicate valence asymmetric vibrations of PO43– groups. Numerous bands for all experimental samples in the wavelength region 3900-3500 cm–1 can be caused by vibrations of OH groups, which is associated with the presence of water in the tested samples. Comparison of the absorption intensity in the region of characteristic frequencies of collagen and hydroxyapatite calculated by the IR method can be one of the approaches for the development of a rapid method for the determination of their quantitative content in fractions obtained from fish scales. Organic and mineral additives from fish scales can be recommended as components of formulations of various food products, as well as raw materials in tissue engineering, orthopedics and dentistry.

Very Strong Hydrogen Bond in Nitrophthalic Cocrystals.

This work presents the studies of a very strong hydrogen bond (VSHB) in biologically active phthalic acids. Research on VSHB comes topical due to its participation in many biological processes. The studies cover the modelling of intermolecular interactions and phthalic acids with 2,4,6-collidine and N,N-dimethyl-4-pyridinamine complexes with aim to obtain a VSHB. The four synthesized complexes were studied by experimental X-ray, IR, and Raman methods, as well as theoretical Car-Parrinello Molecular Dynamics (CP-MD) and Density Functional Theory (DFT) simulations. By variation of the steric repulsion and basicity of the complex' components, a very short intramolecular hydrogen bond was achieved. The potential energy curves calculated by the DFT method were characterized by a low barrier (0.7 and 0.9 kcal/mol) on proton transfer in the OHN intermolecular hydrogen bond for 3-nitrophthalic acid with either 2,4,6-collidine or N,N-dimethyl-4-pyridinamine cocrystals. Moreover, the CP-MD simulations exposed very strong bridging proton dynamics in the intermolecular hydrogen bonds. The accomplished crystallographic and spectroscopic studies indicate that the OHO intramolecular hydrogen bond in 4-nitrophthalic cocrystals is VSHB. The influence of a strong steric effect on the geometry of the studied cocrystals and the stretching vibration bands of the carboxyl and carboxylate groups was elaborated.

Accelerated multistep thermal stabilization of polyacrylonitrile fibers using an ethylenediamine pretreatment

The polyacrylonitrile multifilament yarn underwent a multistep heat treatment process including stabilization times ranging from 5 to 75 min following impregnation with a 30% ethylenediamine (EDA) aqueous solution. A series of measurements were employed to determine the structure and properties of thermally stabilized PAN samples. These included fiber thickness, fiber density, flame testing, tensile testing, X-ray diffraction, thermal analysis (differential scanning calorimetry and thermogravimetric analysis), and infrared spectroscopy. The results from XRD and IR spectroscopy indicated that the rate of aromatization reactions increased with longer stabilization times. A detailed examination of the XRD curves obtained through curve-fitting procedures suggested a rapid transformation of the original structure into a disordered amorphous phase containing pre-graphitic domains, evidenced by a gradual reduction in the degree of apparent crystallinity of the original PAN sample. The integration of EDA before the thermal stabilization stage significantly reduced the cyclization time of nitrile groups in the PAN polymer structure, thereby accelerating the stabilization reactions. This chemical pretreatment also improved the thermal stability of the samples by promoting oxidative cross-linking of the PAN polymer chains. After a 75 min multistep stabilization, the carbon yield at 1000 °C was 70.5%. Conversion index values, calculated using IR, XRD, and DSC methods, were 98.3%, 94.8%, and 89.5% respectively for the 75 min sample. These findings highlight the importance of EDA in accelerating the formation of an aromatic structure, which is critical for withstanding the high temperatures of subsequent carbonization stages.Graphical abstract

Synthesis, characterization, and investigation of antibacterial and antifungal properties of salt and metal complexes of 2-amino-5-chloropyridine and 2,6-pyridinedicarboxylic acid

In this study, the salt (3) of 2-amino-5-chloropyridine (1) and 2,6-pyridinedicarboxylic acid (2) and the complexes of the salt (H1)x[M(2)2].nH2O, M = Fe (III), x = 1, n = 3 (4); M = Co(II), x = 2, n = 4 (5); M = Ni(II), x = 2, n = 5 (6); M = Cu(II), x = 2, n = 4 (7)} were synthesized. The structures of 3-7 were suggested by NMR, AAS, IR, UV, magnetic susceptibility and molar conductivity methods. As a result of spectroscopic analysis, it was observed that all metal complexes had an ionic and octahedral structure. All substances were susceptible to Candida albicans (yeast), Escherichia coli, Bacillus subtilis, Enterococcus faecalis, Pseudomonas aeruginosa, Listeria monocytogenes and Staphylococcus aureus bacteria were examined. Antimicrobial activity results were compared with Fluconazole, Ketoconazole, Chloramphenicol, Levofloxacin, Vancomycin and Cefepime. In the activity results, the best values were observed 3, 5 and 7 in S. aureus bacteria, 1 and 5 in E. coli bacteria, 1, 3 and 7 in P. aeruginoa bacteria, all compounds in L. monocytogenes bacteria, all compounds (except 4) in E. faecalis bacteria, 1 and 3-5 in B. subtilis bacteria and 3, 4 and 7 in C. albicans yeast.

Arene ruthenium(II) complexes with 3-acetyl coumarin derivatives bearing a 3-hydroxy-2-naphthoic hydrazide moiety: Synthesis, DFT calculations and antioxidant studies

The reaction of [(arene)RuCl2]2 with coumarin hydrazone ligands in methanol yielded neutral chelating mononuclear N∩O metal complexes having the general formula [(arene)Ru(L)Cl] where arene = p-cymene, benzene; and L = 3‑hydroxy-N'-(1-(2-oxo-2H-chromen-3-yl)ethylidene)-2-naphthohydrazide (L1), 3‑hydroxy-N'-(1-(7‑methoxy-2-oxo-2H-chromen-3-yl)ethylidene)-2-naphthohydrazide (L2), (E)-N'-(1-(6‑bromo-2-oxo-2H-chromen-3-yl)ethylidene)-3‑hydroxy-2-naphthohydrazide (L3) and 3‑hydroxy-N'-(1-(3-oxo-3H-benzo[f]chromen-2-yl)ethylidene)-2-naphthohydrazide (L4)}. All complexes (1–8) were fully characterized by spectroscopic techniques like IR, UV–Vis, NMR and ESI-MS spectral methods. The solid-state molecular structures of the three complexes were determined using a single-crystal X-ray diffraction study. The studies revealed that the ligands binding mode to the ruthenium metal centers is through the azomethine nitrogen and the imidolate oxygen forming a five-membered chelating ring. All the complexes and the ligands were screened for antibacterial and antioxidant activity studies. Some of the complexes exhibited antioxidant activity that is more prominent than their respective ligands.

Liquid crystalline polyurethane/POSS hybrid nanocomposites pyrolysis studies by Py-GC/MS and TG/FTIR techniques

The process of pyrolysis of liquid crystalline polyurethane (LCPU) composites with polyhedral oligomeric silsesquioxanes (POSS) has been studied using pyrolysis - gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetry/Fourier transform infrared spectroscopy (TG/FTIR) coupled thermoanalytical techniques. LCPU elastomers modified with POSS molecules with different architectures, bearing aromatic, isobutyl and cycloaliphatic moieties, yield various volatile products of pyrolysis that were collected and characterized. The TG study showed significant differences in the thermal behavior of composites studied, evidencing the influence of the silsesquioxane type on the polyurethane pyrolysis paths. FTIR study of volatile products of thermal decomposition showed the presence of characteristic bands originated from carbonyl, amine, ether, methylene, and unsaturated hydrocarbon linkages. GC/MS investigation confirmed the existence of compounds identified by the IR method. The application of both thermoanalytical methods made it possible to postulate the thermal decomposition routes of PU/POSS hybrids and to point out the main factors responsible for changes in the thermal stability.

Tuning Green Explosives through SNAr Chemistry.

Reactivity and regioselectivity of SNAr-type fluorine substitution with azide in polyfluorosubstituted nitrobenzenes was studied both theoretically and experimentally. The obtained polyazido-substituted nitrobenzene derivatives were extensively characterized by NMR, IR, HPLC, X-ray, and DFT methods. It was found that the substitution with the azide nucleophile occurs first at the para- and the ortho-positions to the NO2-group and that transazidation reactions also occur here. Thermal decomposition of prepared azidonitrobenzenes was studied both in controlled (kinetic decay) and uncontrolled (explosion) modes. In case of the controlled thermal decomposition of ortho-azidonitrobenzenes, benzofuroxans were found as major products of the reaction unless another azido group was adjacent to the furoxan moiety. The bursting power of azidonitrobenzenes was found to rise gradually with the number of the azide substituents in the aromatic ring.

Removal of Anionic Methyl Orange Dye from Water by Poly[2-methyl-1H-indole] Derivatives: Investigation of Kinetics and Isotherms of Adsorption.

The adsorption properties toward methyl orange (MO) were evaluated for poly[2-methyl-1H-indole] and its derivatives. The influence of pH, ionic strength of solution, composition, and amount of sorbent on the adsorption of MO dye was investigated; the kinetics of dye adsorption was studied. The adsorption isotherms were analyzed using different models of sorption equilibrium. The presence of chemical interaction between polyindoles and dye was proved by IR and UV spectroscopy methods. The sorption of MO with polymers is realized mainly due to the formation of electrostatic interactions between the sulfogroup of the dye and the imino group of the sorbent. Microphotographs demonstrate the change in the morphology of polyindoles after adsorption, which further confirms the structural changes in the polymers. It was found that the main factors affecting the sorption capacity of the studied materials are the position and nature of substituents in the polymers and the sorption conditions. For example, polyindoles containing a methoxy group in their structure (o-OMePIn and m-OMePIn) have the best sorption activity. These polymers are effective in adsorbing dyes, which means that they can be used in wastewater treatment.

ISOLATION OF FULVIC ACID FROM COAL AND STUDY OF PHYSICAL AND CHEMICAL PROPERTIES

Due to its high solubility and low molecular weight, fulvic acid is a very active participant in natural chemical processes. Due to its smaller molecule size than humic acid, it can act both inside and outside the cell. The work presents the method of isolation and purification of fulvic acid obtained from oxidized brown coal and the analysis of its physical and chemical properties by the methods of IR, NMR spectroscopy, and the amount of carboxyl and hydroxyl groups studied. Conducted work on calculation of equilibrium constant (pK) and concentration (C). Stages of purification: adsorption, ion purification and dialysis, where adsorbents obtained from brown ("Shoptykol") and hard ("Shubarkol") coal and coconut activated carbon were used as adsorbents.