Quantum Mechanical Parameters Research Articles

Synthesis, characterization, anticancer activity, molecular docking and DFT calculation of 3-acetylcoumarin thiosemicarbazones and Schiff’s bases

The new thiosemicarbazones (3a-d) of 3-acetylumbelliferone and Schiff’s bases (4a-b) of 3-acetylcoumarin were synthesized, characterized by elemental analysis, UV–Vis, FT-IR, NMR, and ESI-HR MS, and evaluated for their anticancer potency against the human breast cancer (MCF-7) cell line. All the tested compounds exhibited good to moderate anticancer efficacy in a dose-dependent manner. The synthesized compounds exhibited potent preferential inhibition effects against the MCF-7 cell line, with IC50 range of 147.8–505.1 µg/mL. The most potent compound, (E)-N-(1-(7-hydroxy-2-oxo-2H-chromen-3-yl) ethylidine)-2,6-dimethylmorpholine-4-carbothiohydrazide (3c), showed significant cytotoxicity with an IC50 value of 147.8 µg/mL against the tested cell line. It showed a higher proportion of cells in G1 (37.21 %) and S (26.86 %) phases and a lower proportion of cells in G2 phase (26.37 %), with respect to control. Molecular docking of all the synthesized compounds with target proteins VEGFR2 and EGFR demonstrated their significant binding affinity and interactions with key residues compared to the reference drug (erlotinib). DFT-based analysis showed that all the compounds have effective reactivity due to the low band gap energy of HOMO and LUMO relative to the reference drug, erlotinib (4.26 eV). The reactivity-related quantum mechanical parameters η, S, χ, μ, and ω indicated that these compounds have a high efficacy towards the target enzymes VEGFR2 and EGFR. All of the synthesized compounds had drug-like action, according to ADMET predictions.

Synthesis, characterization, and antibacterial effectiveness of gemifloxacin C-3 modified amide analogs: A theoretical and experimental approach

In search of a newer, efficient, and adaptable antimicrobial solution to combat the resistance that has developed due to the widespread extensive and in appropriate use of antibiotics. Seven new amide analogs of Gemifloxacin (G-D01-G-D07), an important member of the fluoroquinolone (FQ's) was synthesized by modifying the C-3 position in a quick and facile way, using Schotten Baumann reaction approach exhibiting highly efficient yields and short reaction times. Their in-silico pharmacokinetic and toxicity studies were determined by SwissADME and Protox-II webserver, and found that all the compounds obeys the lipinski's rule and didn't exhibit any vital organ toxicity. The introduction of selected amines to form amide analogs (G-D01-G-D07) was assured by their spectroscopic characterization, structural stability studies by DFT parameters and Microbiological assay evaluates these synthesized analogs as potent antibacterial and antifungal agents against studied species. At the B3LYP/6–311 G level of theory, the molecular structures, reactivity, and electronic characteristics of candidate compounds exhibiting the most promising antibacterial actions were examined, and their quantum mechanical parameters were calculated. The energy gaps of all the synthesized compounds were found in ranges between 0.1088 and 0.1091 eV, indicating good softness, thermal and kinetic stability. This can be correlated by the activity of these analogs against Klebsiella pneumonia, and Citrobacter freundii, where synthesized derivatives G-D06 and G-D03, G-D04, and G-D07 exhibit activities more than the parent drug. The binding affinity of complexes revealed by docking was found in the range between -14.31 and -16.20 kcal/ mol, which indicates their high antibacterial potential against one of the major targets Klebsiella pneumoniae cytidine deaminase CDA protein by using AutoDock Vina and MD simulations by GROMACS, confirming them as potential antibacterial agents.

Theoretical Study and Virtual Screening of Nitrogen‐Containing Corrosion Inhibitors Based on Quantitative Structure–Activity Relationship

AbstractNitrogen‐containing corrosion inhibitors have a wide range of promising applications, and current conventional corrosion design and evaluation methods are largely based on empirical speculation and extensive exploratory experiments. Unfortunately, these efforts are often associated with high costs, long lead times, and a lot of “blind work.” In this work, we have computationally screened the quantum chemical parameters of five nitrogen‐containing corrosion inhibitor molecules and their corrosion inhibition properties by a molecular simulation method based on density functional theory calculations. The ultimate relationship between the corrosion inhibition efficiency (IE) of an adsorbent and its quantum chemical parameters was analyzed using linear regression by comparing the various quantum mechanical parameters of each inhibitor molecule, as well as the fraction of electrons (ΔN) that are transferred to the metal surface from the chemisorbed inhibitor molecule. Five different nitrogen‐containing corrosion inhibitor molecules were screened based on structural similarity. Meanwhile, their corrosion inhibition performance was evaluated using the most relevant structure–activity equations. The results showed that the synergistic effect between the corrosion inhibition performance and the orbital energies of highest occupied molecular orbital and lowest unoccupied molecular orbital was optimal under the HF/6‐31G(d) method, and the corresponding structure–activity relationship was established. Based on these results, a specific inhibitor molecule was found to have excellent corrosion inhibition performance with a predicted corrosion IE of up to 94.12 %.

Microscopic quantum mechanical Marcus theory for chemical reactions and its relationship to theButler‐Volmerequation used in redox flow battery analysis

AbstractThe vanadium redox flow battery has been intensively examined since the 1970s. What is missing is a connection between the current‐overpotential Butler‐Volmer equation, which provides an extremely helpful starting point for analytical and numerical studies, and microscopic quantum mechanical behavior at the atomic level. Such a connection will allow further advancements beyond the macroscopic, though very useful and insightful, modeling already done in the literature. Here we show rigorously the connection between the Butler‐Volmer transfer coefficients, and the Marcus Gibbs free energy quantum mechanical parameters, and develop the equation directly in terms of the quantum mechanical parameters.

Classical Fisher information for differentiable dynamical systems.

Fisher information is a lower bound on the uncertainty in the statistical estimation of classical and quantum mechanical parameters. While some deterministic dynamical systems are not subject to random fluctuations, they do still have a form of uncertainty. Infinitesimal perturbations to the initial conditions can grow exponentially in time, a signature of deterministic chaos. As a measure of this uncertainty, we introduce another classical information, specifically for the deterministic dynamics of isolated, closed, or open classical systems not subject to noise. This classical measure of information is defined with Lyapunov vectors in tangent space, making it less akin to the classical Fisher information and more akin to the quantum Fisher information defined with wavevectors in Hilbert space. Our analysis of the local state space structure and linear stability leads to upper and lower bounds on this information, giving it an interpretation as the net stretching action of the flow. Numerical calculations of this information for illustrative mechanical examples show that it depends directly on the phase space curvature and speed of the flow.

Organotellurium(IV) complexes derived from thiophene based Schiff base 5-methyl-2-thiophene carboxaldehyde: Synthesis, spectral characterization, thermal analysis potent antimicrobial and antioxidant activities supported by molecular docking, DFT studies and ADMET prediction

Keeping in view, the widespread of contagious diseases, we have prepared an important class of organotellurium(IV) complexes to cure these ailments, comprising condensation reaction between 5-methyl-2-thiophene carboxaldehyde and p-aminophenol resulting in the synthesis of 5-methyl-2-thiophene carboxaldehyde p-aminophenol (5MTCPAP) Schiff base, which on further reactions with organotellurium(IV) chlorides (R2TeCl3 and RTeCl2) leads to 6 new hexacoordinated complexes similar to RTeCl3.5MTCPAP and R2TeCl2.5MTCPAP. These complexes were distinguished by numerous experimental and spectral approaches like FT-IR, Mass spectrometry, Powder XRD, DFT calculations, Molar conductance, 1H NMR, 13C NMR, TGA. These spectroscopic data, evidently proves that Schiff base ligand act as bidentate NS chelating agent. def2-SVP and def2-T2VPP is used for optimization and calculation of quantum mechanical parameters of geometries of 5MTCPAP and its Te(IV) complexes. According to the result of spectral studies, complexes tend to have distorted octahedral geometry. Computational studies and pharmacological activities were investigated for ligand and its tellurium(IV) complexes. The molecular docking of complexes executed on the field of action of E. coli (3 t88), S. aureus (4dxd), C. albicans (5fsa) illustrates assuring interactions and recommends decent biological response. DPPH assay was carried out to study the antioxidant study of Schiff base and complexes, taking ascorbic acid as standard. In-vitro pharmacological analysis (antimicrobial as well as antioxidant) designates that the Schiff base ligands upon complexation, exhibits improved biological effectiveness. In-silico ADMET studies were involved to examine therapeutic characteristics of 5MTCPAP and its organotellurium (IV) complexes.

Quantum Mechanics Modeling of Oxetanes as Epoxide Hydrolase Substrates

Background: Epoxide hydrolases comprise an important class of enzymes that have critical functions in the detoxification of xenobiotics and regulation of signaling molecules. In addition to epoxides, oxetanes have recently been identified as novel substrates of microsomal epoxide hydrolase (mEH). Oxetanes are common scaffolds used in medicinal chemistry design to improve potency and drug-like properties. Metabolism of oxetanes by mEH can result in high uncertainties in the prediction of human clearance due to extrahepatic contribution and large interindividual variability. Therefore, reducing mEH-mediated oxetane metabolism is highly desirable to minimize its contribution to clearance. Objective: The aim of the study is to evaluate whether quantum mechanical parameters are able to predict the hydrolytic rate of mEH-mediated oxetane metabolism in order to guide medicinal chemistry design in order to minimize mEH contribution to clearance. Methods: Quantum mechanics modeling was used to evaluate the hydrolytic rate of twenty-three oxetanes by mEH. All modeling studies were performed with the Maestro software package. Results: The results show that LUMO energy is highly correlated with the diol formation rate of oxetane hydrolysis by mEH for compounds that are structurally similar, while other quantum mechanical parameters are less predictive. The data suggest that the intrinsic reactivity determines the hydrolytic rate of oxetanes. This occurs when the orientations of the molecules in the mEH active site are similar. Predictions of mEH substrate metabolic rates using LUMO are most accurate when comparing subtle structural changes without drastic changes in MW and chemotype. Conclusion: The study suggests that LUMO energy can be used to rank-order oxetanes for their hydrolytic rate by mEH for structurally similar compounds. This finding enables the medicinal chemistry design to reduce mEH-mediated oxetane metabolism based on the calculated LUMO energy.

Insight on the structural, electronic and optical properties of Zn, Ga-doped/dual-doped graphitic carbon nitride for visible-light applications

The density functional theory (DFT) was applied for the first time to study the doping and co-doping of Ga and Zn metals on graphitic carbon nitride (g-C3N4). The doping of these metal impurities into g-C3N4 leads to a significant decrease in the bandgap energy. Moreover, the co-doping leads to even lower bandgap energy than either individual Zn or Ga-doped g-C3N4. The theoretical electronic and optical properties including the density of state (DOS), energy levels of the frontier orbital, excited state lifetime, and molecular electrostatic potential of the doped and co-doped g-C3N4 support their application in UV–visible light-based technologies. The quantum mechanical parameters (energy band gap, binding energy, exciton energy, softness, hardness) and dipole moment exhibit higher values (ranging from 1.36 to 4.94 D) compared to the bare g-C3N4 (0.29 D), indicating better solubility in the water solvent. The time-dependent DFT (TD-DFT) calculations showed absorption maxima in between the UV–Vis region (309–878 nm). Additionally, charge transfer characteristics, transition density matrix (TDM), excited state lifetime and light harvesting efficiency (LHE) were investigated. Overall, these theoretical studies suggest that doped and co-doped g-C3N4 are excellent candidates for electronic semiconductor devices, light-emitting diodes (LEDs), solar cells, and photodetectors.

Ultra-Sonicated One-Pot Synthesis of Potent Bioactive Biscoumarin and Polycyclic Pyranodichromenone Scaffolds in Aqueous Media: A Complementary Tool to Organic Synthesis

AbstractPresent study involves the synthesis of bis-coumarins and novel polycyclic pyranodichromenones using a catalyst-free approach under ultrasonic irradiation in an aqueous medium. The chemical structures of the synthesized compounds were characterized using FTIR, 1H NMR, and 13C NMR spectroscopy. The antibacterial and antifungal activities of the compounds were evaluated against Gram-positive (S. aureus, B. cereus) and Gram-negative bacteria (P. aeruginosa, E. coli), as well as the fungus C. albicans, using the disc diffusion method. Several compounds exhibited excellent activity against the tested microorganisms. Moreover, the antioxidant potential of the synthesized products was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethyl­benzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging, and total antioxidant capacity (TAC) assays. Promising antioxidant activity was observed for certain compounds. Computational studies using density functional theory (DFT) were conducted to investigate the molecular reactivity and electronic properties of the synthesized compounds. Quantum mechanical parameters such as Ionization Potential (IP), Electron Affinity (EA), Mulliken Electronegativity (χ), Chemical Potential (μ), and Electrophilicity Index (ω) were calculated. The study highlights the efficiency and eco-friendliness of ultrasonic-assisted processes, contributing to the advancement of sustainable chemistry.

Effective corrosion inhibition of mild steel using novel 1,3,4-oxadiazole-pyridine hybrids: Synthesis, electrochemical, morphological, and computational insights

An easy synthesis of two 1,3,4-oxadiazole derivatives, namely, 2-phenyl-5-(pyridin-3-yl)-1,3,4-oxadiazole (POX) and 2-(4-methoxyphenyl)-5-(pyridin-3-yl)-1,3,4-oxadiazole (4-PMOX), and their corrosion-inhibition efficacy against mild steel corrosion in 1 N HCl, is evaluated using weight loss from 303 to 323 K, Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), UV–Vis spectroscopy, along with theoretical evaluation. Both POX and 4-PMOX exhibit excellent inhibition efficiency, with values reaching 97.83% and 98% at 500 ppm, respectively. The PDP analysis reveals that both derivatives act as mixed-type inhibitors. The Langmuir adsorption isotherm provides insights into the adsorption phenomena, demonstrating that 4-PMOX exhibits superior adsorption behavior on the mild steel surface compared to POX. This finding is further supported by SEM, DFT, RDF, and MSD analyses. Quantum mechanical parameters, including EHOMO, ELUMO, dipole moment (μ), energy gap (ΔE), etc., are in good agreement with the effectiveness of inhibition performance revealing ΔE values of 3.10 and 2.75 for POX and 4-PMOX, respectively. The results obtained from this study hold significant implications for researchers aiming to design more efficient organic inhibitors to combat metal corrosion.

New ferrocene integrated amphiphilic guanidines: Synthesis, spectroscopic elucidation, DFT calculation and in vitro α-amylase and α-glucosidase inhibition combined with molecular docking approach

Three N, N’, N″-trisubstituted ferrocenyl guanidines (MG-10, MG-12 and MG-14) were synthesized, characterized by several analytical methods such as FT-IR, 1H and 13C NMR, elemental analysis and UV–visible spectroscopy. These compounds have long chain aliphatic groups therefore their aliphatic nature has been evaluated by determining their critical micelle concentration (CMC). CMC point decreases from 0.036 mM to 0.013 mM with increase in the aliphatic chain length. The quantum mechanical parameters such as the energy of frontier molecular orbitals (EHOMO and ELUMO) and the Mulliken charge distribution on the optimized structures were determined using a DFT/B3LYP method combined with the 6-31G (d,p) basis set in the gas phase. The in vitro antidiabetic activity of synthesized compounds showed that MG-12 has IC50value 23.10 μg/mL against α-amylase while MG-10 has IC50value 27.32 μg/mL against α-glucosidase with the respective standard Acarbose (IC50value 20.12 μg/mL). Theoretical docking analysis demonstrated that MG-10 and MG-12 interacted with α-amylase by 3 types of interaction, including hydrogen bonds, hydrophobic interactions and electrostatic interactions.

A Physical Organic Approach towards Statistical Modeling of Tetrazole and Azide Decomposition.

Nitrogen atom-rich heterocycles and organic azides have found extensive use in many sectors of modern chemistry from drug discovery to energetic materials. The prediction and understanding of their energetic properties are thus key to the safe and effective application of these compounds. In this work, we disclose the use of multivariate linear regression modeling for the prediction of the decomposition temperature and impact sensitivity of structurally diverse tetrazoles and organic azides. We report a data-driven approach for property prediction featuring a collection of quantum mechanical parameters and computational workflows. The statistical models reported herein carry predictive accuracy as well as chemical interpretability. Model validation was successfully accomplished via tetrazole test sets with parameters generated exclusively in silico. Mechanistic analysis of the statistical models indicated distinct divergent pathways of thermal and impact-initiated decomposition.

A Physical Organic Approach towards Statistical Modeling of Tetrazole and Azide Decomposition**

AbstractNitrogen atom‐rich heterocycles and organic azides have found extensive use in many sectors of modern chemistry from drug discovery to energetic materials. The prediction and understanding of their energetic properties are thus key to the safe and effective application of these compounds. In this work, we disclose the use of multivariate linear regression modeling for the prediction of the decomposition temperature and impact sensitivity of structurally diverse tetrazoles and organic azides. We report a data‐driven approach for property prediction featuring a collection of quantum mechanical parameters and computational workflows. The statistical models reported herein carry predictive accuracy as well as chemical interpretability. Model validation was successfully accomplished via tetrazole test sets with parameters generated exclusively in silico. Mechanistic analysis of the statistical models indicated distinct divergent pathways of thermal and impact‐initiated decomposition.

DFT, NBO, Fukui Functions and Monte Carlo Studies on Quinoline Derivatives for Corrosion Inhibition Property

The corrosion inhibiting property of 4-methylquinoline (4MQ) and 4-aminoquinaldine (4A2MQ) by using various quantum mechanical and molecular mechanics parameters such as EHOMO, ELUMO, energy difference (ΔEgap), electrophilicity, nucleophilicity, chemical hardness, chemical softness, adsorption energy on the metal surface, ability of back donation, electron affinity, chemical potential and dipole moment values are studied. Density functional studies were carried out using B3LYP/6-31g++(d,p), B3LYP/6-31g(d,p) and B3LYP/6-31g(d) basis sets. The outputs of the compounds were compared as well as the characteristics of the Fukui functions used to analyze them. The adsorption energy values were obtained using Monte Carlo simulation techniques. The adsorption energy calculations were carried out by using COMPASS force field and adsorption annealing methods. These calculated values had good agreement with previously reported values of these corrosion inhibitors. Comparing the combined dual descriptor values of 4MQ and 4A2MQ reveal that the latter compound readily undergoes electrophilic attack, leading to the enhanced corrosion inhibition. The efficiency of these corrosion inhibitors compounds by various studies was compared and the result shows that 4A2MQ can be better corrosion inhibitor than 4MQ.

Quantum mechanical studies of p-azoxyanisole and identification of its electro-optic activity.

Liquid crystals (LCs) are used in displays, visors, navigation systems and many more. Amongst a wide range of LCs, p-azoxyanisole (PAA) is considered to be an active LC. Focusing on different properties of this molecule, in the reported study, the theoretical identification of quantum mechanical parameters and the identification of electro-optic properties are carried out. Different functional theories such as B3LYP, M06-2X and M06L are used along with three basis sets 6-31G**, 6-311G and 6-311G**. A comparative study revealed that the M06-2X method produces higher values of band gap, ionization potential, electronegativity and electronic global hardness while M06L produces lower values and B3LYP gives intermediate values. Nonlinear optical properties of liquid crystals are evaluated. The nonlinear optical properties obtained for a PAA liquid crystal are much higher than those of urea. Due to its high nonlinear optical properties, our liquid crystal can be used in the field of telecommunication and optical interconnection. The order parameter and birefringence are calculated with variable electric field. We found out that the order parameter and birefringence increase with a gradually increasing electric field, which suggests that the PAA liquid crystal can be used for developing electro-optic and tunable metamaterial devices.

Organotellurium(IV) complexes of N-methylisatin-o-aminothiophenol Schiff base: Preparation, characterization, DFT, molecular docking studies, antimicrobial and antioxidant activity

The reactions of organotellurium(IV) chlorides (RTeCl3 and R2TeCl2) with Schiff base(NMeIATP) derived by condensation of N-methylisatin with 2-aminothiophenol results in the formation of new organotellurium(IV) complexes (4a-4f) of type RTeCl2.NMeIATP and R2TeCl.NMeIATP (where R = 4-Methoxyaryl, 4-Hydroxyaryl and 3-Methy-4-hydroxyaryl; aryl = phenyl). These complexes were characterized by different experimental and spectroscopic techniques like elemental analyses, molar conductance, SEM analysis, FT-IR, DFT calculations, powder X-ray diffraction, mass spectrometry, 1H NMR, 13C NMR, UV–Vis and Thermogravimetric analysis. These spectroscopic studies revealed that ligand acted as monobasic tridentate ligand coordinated with tellurium metal through Carbonyl oxygen, azomethine nitrogen and sulphur atom from the 2-aminothiophenol ring. The molecular geometries of NMeIATP and its organotellurium(IV) complexes(4a-4f) were optimized and quantum mechanical parameters were calculated by using DFT/B3LYP basis sets in Guassian09 program. Based on the spectral results, suitable geometries of the complexes are purposed. Molecular docking studies were carried out to determine the binding energy between NMeIATP and complexes with receptor proteins: S. aureus (3ty7), B. subtilis (5h67) and E. coli (3t88). Antioxidant activity of NMeIATP and organotellurium(IV) complexes were evaluated by DPPH assay. The radical scavenging activity(IC50 value) of complex 4a (IC50 = 59.08 μg/ml) was found to be greater than other compounds. NMeIATP and organotellurium(IV) complexes were tested against different bacteria and fungi. MIC values show that complexes possess better antimicrobial activity than Schiff base (NMeIATP).

Аналіз структурно-хімічного стану дуплекс-систем силікати-силіциди лужно-земельних металів. Повідомлення 1.

The classification and structuring of oxide and metallic phases of binary duplex systems of silicates-silicides of alkaline earth metals are carried out in the work. This will determine the optimal composition of alkaline earth metal alloys based on silicon in the refining of ferrocarbon melts and modification of non-metallic inclusions. The ionic-molecular complexes of magnesium, oxygen and silicon are constructed in the work, which determine the mechanism of formation of non-metallic inclusions (magnesium silicates) in steel when using silicomagnesium alloys for refining. The parameters of chemical bonding for oxides with ionic bond type, for liquid silicomagnesium alloys having a metallic type of chemical bonding and for hard alloys with metal-covalent bond are determined. The presented results of structural and chemical analysis of the duplex system MgO–SIO2–Mg–Si allow to reveal the mechanisms of desulfurization processes and to develop technologies of blast furnace desulfurization in smelting and ladle treatment with furnace slag, magnesium and its alloys with silicon. Keywords: polygonal diagram, magnesium oxides, alkaline earth metal silicides, quantum mechanical parameters, classification and structuring.

STUDY OF QUANTUM MECHNICAL PARAMETERS OF 1, 1ʹ BIS (THIOCYNATO MERCURIO) FERROCENE WITH THE HELP OF DENSITY FUNCTION THEORY

Recently density function theory attained great prominence in quantum chemistry research. Calculation of quantum mechanical parameters viz. energies of binding orbitals, heat of formation, total energy, electronic energy, core-core repulsion etc. have been done with the help of density function theory using CAChe software for the complex 1,1ʹ bis (thiocyanatomercurio) ferrocene. Bonding orbital energies and core-core repulsion values indicate the comparative stability of the complexes.

Synthesis and quantum mechanical characterization of three new 1-(5-nitro-benzimidazole-2′-yl-sulfonyl-acetyl)- 4-aryl-thiosemicarbazide with biological potential

The paper contains the results obtained in grafting the acyl-thiosemicarbazide on the holder molecule 5-nitro-benzimidazol-2-sulfonyl-acetic acid by oxidation reaction of 5-nitro-benzimidazol-2-yl-mercapto-acetic acid, then passed to the corresponding sulfonyl hydrazide. Acyl-thiosemicarbazides containing the sulfonyl group were obtained. The chemical structure of the newly obtained compounds was confirmed by spectral analysis (FT-IR, 1H-NMR). This article aims with spectral and quantum-chemical characterization of three new thiosemicarbazides with potential tuberculostatic action. The reaction way, the main IR and NMR peaks and the quantum-mechanical parameters, computed with Spartan’14 program are estimated. The tuberculostatic of action is analyzed compared with reference drug isoniazid.

Аналіз структурно–хімічного стану дуплекс–систем силікати–силіциди лужно–земельних металів. Повідомлення 2. Дуплекс–система SiO2–MgO–CaO: Si–Mg–Ca

A polygonal diagram of the state of the CaO-SiO2-MgO ternary system was constructed in the entire range of concentrations of solid and liquid initial components, which increases the informativeness of polygonal diagrams of the state of metallurgical systems. The obtained results of the SCS analysis of the silicate and silicide phases of the duplex system SiO2–MgO–CaO : Si–Mg–Ca are the scientific basis for the optimization of blast furnace iron refining processes with smelting slags and magnesium alloys. Keywords: polygonal diagram, magnesium slag, silicate and silicide phases of calcium, physicochemical, technological and quantum-mechanical parameters.