Electrophilic and Nucleophilic Modifiers as a Factor of Formation of Lipophilic Properties of Surface-Modified Materials

Stabilization of the functional properties of dispersed and compact solid metals, as well as regulation of their reactivity, improvement of water-repellent, antifriction and anti-corrosion properties by creating the protective films on the surface is an urgent problem of obtaining resource-saving materials. Previously, the research conducted at REC "Nanotechnology" of Mining University proved that chemisorption of ethylhydridesiloxane vapors together with cationic surfactants based on quaternary ammonium compounds has a beneficial effect on the water-repellent properties of metals. In order to obtain the physicochemical substantiation of the effect of hydrophobization of the surface of modified dispersed metals for the first time, the study of the electrophilic-nucleophilic properties of the active substances of the surface modifiers of dispersed and compact metals was carried out using the methods of quantum-chemical modeling in HyperChem software package. The dipole moment, energy of the highest occupied and the lowest unoccupied molecular orbitals, electrophilic-nucleophilic properties were determined. The series of enhancement of nucleophilic/electrophilic properties and dipole moment for modifiers were obtained. The donor-acceptor properties, the differences in the characteristics of the molecules of alkamone (A), triamone (T) and hydrophobic silicone organic liquid were quantitatively and qualitatively established. The patterns of the formation of hydrophobic properties of the surface during the layering of molecules of ammonium and organosilicon compounds with different electrophilic-nucleophilic properties on dispersed metals have been established. Recommendations for the use of modifiers for the production of high - and superhydrophobic materials are proposed.

Electrophilic-nucleophilic properties as a factor in the formation of antifriction and hydrophobic properties of surface-modified metals with ammonium and organosilicon compounds

Stabilisation of the functional properties of dispersed and compact metals, as well as the regulation of their reactivity, improvement of water-repellent, antifriction and anti-corrosion properties by creating the protective films on the surface is an urgent problem in relation to obtaining new materials. Previously, research conducted at REC “Nanotechnology” of the St. Petersburg Mining University proved that chemisorption of ethylhydridesiloxane vapours together with surfactants based on quaternary ammonium compounds has a beneficial effect on the water-repellent properties of metals. In order to obtain the physicochemical mechanism of the hydrophobisation of the surface of modified dispersed metals for the firsttime, the study of the electrophilic-nucleophilic properties of the active substances of the surface modifiers of metals was carried out using the methods of quantum-chemical modelling using HyperChem software package. The dipole moment, energy of the highest occupied and the lowest unoccupied molecular orbitals, electrophilic-nucleophilic properties were determined. The series of enhancement of ucleophilic/electrophilic properties and dipole moment for modifiers were obtained. The donor-acceptor properties, the differences in the characteristics of the molecules of alkamon, triamon, and hydrophobic silicone organic liquid were quantitatively and qualitatively established. The regularities of the formation of hydrophobic and antifriction properties in the composition of industrial oil I-20-surface-modified metal with various electrophilic-nucleophilic properties of the applied substances

Molecular Docking of Some Quinazolinone Analogues as an EGFR Inhibitors

Background: Mutations that cause high expression of epidermal growth factor can lead to cancer. Therefore, this factor serves as a potential molecular target for cancer treatment, and inhibitors of this enzyme are of particular importance in the treatment of cancer. This study aimed to investigate the bioinformatics of inhibition of EGFR enzyme by a number of quinazolinone derivatives. Materials and Methods: This study was conducted based on a descriptive-analytical method. To investigate how quinazolinone derivatives bind to the active site of the enzyme, the chemical structure of the compounds was first plotted using ChemBioDrawUltra software (version 14). It was then transferred to Hyperchem software for energy optimization. Docking studies were performed using AutoDock software (version 4.2), and in the final stage, the results were analyzed using three programs, including AutoDockTools, DS Visualizer, and Ligplot. Results: Based on the results of docking studies, the most important bonds involved in drug-receptor binding are hydrophobic and hydrogen bonds. Among all the studied compounds, the best docking results are related to compound number 3. This compound with the most negative binding energy level (ΔGbind=-7.53 Kcal/mol) has a greater tendency to bind to key amino acids at the active site of the EGFR. Conclusion: In the end, due to the high effectiveness and docking results, it can be conclude that compound number 3 can be considered an effective erlotinib EGFR inhibitor.

Pharmacological classification of anticancer drugs applying chromatographic retention data and chemometric analysis

The combination of chromatography and chemometrics has been introduced in order to provide information about drug analytes, biological macromolecules, the stationary phase, whose properties are related to molecular pharmacology and rational drug design. In this work a pharmacological classification was made in order to find strategy for predicting an activity of anticancer drugs. Principal Component Analysis (PCA) method has been employed to build some relationship models between the following: lipophilicity parameters of selected antitumor drugs obtained by chromatographic analysis, some molecular modeling descriptors from HyperChem software, lipophilicity parameters calculated by proper program, biological activity, as well as mechanism of actions and therapeutic properties of selected anticancer drugs. The most significant influence on factors value had parameters, which described compounds’ lipophilicity. Important debt on antitumor properties had some other molecular descriptors, which were considered in this paper (e.g. topological, physico-chemical, and energy ones). In addition, distribution of individual drugs on plots determined by two principal components had shown points in good accordance with their chemical structures and cytostatic activity as well as their mechanism of actions and therapeutic properties.

КОМПЬЮТЕРНОЕ МОДЕЛИРОВАНИЕ КАК ОДИН ИЗ КОМПОНЕНТОВ ВНЕУРОЧНОЙ ДЕЯТЕЛЬНОСТИ ПО ХИМИИ В СТАРШЕЙ ШКОЛЕ

Анализируется понятие «внеурочная деятельность» в школьном образовании. Охарактеризованы особенности внеурочной деятельности. Приведено понятие «внеурочная деятельность по химии», выделена ее цель и специфическая особенность на старшей ступени обучения в современной школе. Обоснована необходимость выполнения проектов по химии. Предложено одно из актуальных направлений: деятельность обучающихся по моделированию строения веществ. Описана методика работы обучающихся с программами Gaussian и GaussView, используемыми для решения задач квантово-механического моделирования молекулярных структур. Дана характеристика индивидуальным проектам по химии, приведены этапы их выполнения. Показан пример построения обучающимися молекулярных структур хлоридов 15-й группы периодической системы. Представлены результаты оценивания выполненных проектов на основе разработанных критериев и анкетирования с целью определения отношения обучающихся к компьютерному моделированию молекул.The analysis of the concept of «extracurricular activities» in school education is given, its features are characterized. The concept of «extracurricular activities in chemistry» is given, its purpose and specific feature at the senior level of education in a modern school are highlighted. The necessity of carrying out chemistry projects is substantiated, and one of the relevant areas is proposed: design activities of schoolchildren in modeling the structure of substances. The HyperChem software package, which is used to solve the problems of quantum-mechanical modeling of atomic and molecular structures, is described, which allows performing complex computational problems in chemistry in a short period of time. The methodology of work of schoolchildren with the HyperChem software package is described. The characteristic of individual chemistry projects is given, the stages of their implementation are given. An example of the construction by schoolchildren of the molecular structures of chlorides of elements of group 15 of the periodic system and their optimization by the semiempirical PM3 method, which includes only valence electrons in the calculation, is shown. Correlation dependences of the experimental and calculated bond lengths and bond angles, correlation equations, correlation coefficients (R), and standard deviation (SD) are presented. The results of evaluating completed projects on the basis of developed criteria, assessment scales and student performance on completed projects are presented. Questions were developed for questioning students in order to determine their attitude to the GaussView program.

Molecular docking study of oligonucleotides with D-mannitol

Aim. Complex of yeast RNA and D-mannitol has a specific antiviral activity. This complex inhibits the neuraminidase and hemagglutinin activity of viruses such as influenza, parainfluenza and thus it blocks virus entry into the cell and his replication. So, nowadays, study of the interaction of this compound is an important task. Study interaction of the oligoribonucleotides and oligodesoxynucleotides with D mannitol molecule. Methods. Molecular modeling structure of oligoribonucleotides and oligodesoxynucleotides were done by using «Hyperchem» software package. The AutoDock program was used to perform accuracy molecular docking. Results. Were obtained binding energies of D-mannitol molecule with oligoribonucleotides and oligodesoxynucleotides. We have shown the possible connections between atoms of oligonucleotides and D-mannitol molecule. Conclusions. The modeling results should give more detailed information about nature of the oligonucleotides binding with a shugar alcohol D-mannitol.Keywords: molecular docking, oligonucleotides, D-mannitol, binding energies.

Conformational Change of Mutant form of Amyloid Precursor Protein by Carbon Nanotube Functionalized with Morin

The aim of this study was to find the effect of carbon nanotube functionalized with Morin molecule (CNTFM) on normal and mutant forms of amyloid precursor protein (APP), found in Alzheimer’s disease. In this study, one mutant and one normal APP were separately modeled in Hyperchem software. After minimization of system energy, molecular dynamic (MD) simulation was separately carried out for 30[Formula: see text]000[Formula: see text]ps in NVT ensemble at 310[Formula: see text]K. At the end of simulation, different parameters, such as free energy, intermolecular energy and root mean square displacement (RMSD) were separately monitored for each APP. Finally, the ratio of change was calculated for each parameter. To confirm simulation results, one mL of mutant APP (10 mM) was incubated with one mL of CNTFM (10[Formula: see text]mg/mL) for 1[Formula: see text]h. Finally, the percentages of the different secondary structures of both treated and untreated APP were separately estimated by FTIR analysis. Based on MD simulation, high ratio of change was seen for mutant APP. Experimental study showed that the proportion of [Formula: see text]-sheets (parallel [Formula: see text] anti-parallel) and random coil was decreased when incubated with CNTFM. Moreover, the proportion of [Formula: see text]-turns was increased. Interestingly, the proportion of [Formula: see text]-sheets (anti-parallel) was not changed.

ANALYSIS OF CHITOSAN/POLYVINYLPYRROLIDONE (STRUCTURE, FTIR, ELECTROSTATIC POTENTIAL, HOMO/LUMO ORBITALS) USING COMPUTATIONAL CHEMISTRY

Chitosan and PVP oligomers were analyzed by means of the HyperChem software 8.0v to determine the theoretical structure. Quantum chemical calculation of geometrical structure and energies were studied using PM3 and AM1 methods in where the Gibbs free energy was calculated with a value of -9028 and -5796 Kcal/mol, respectively; these values showed that the reaction was carried out. Quantum chemical calculations are applied to study the (CT) complexes in order to obtain information on structures and other molecular properties like specific interaction of donor and acceptor. The interaction energy contribution comes from the effects of donor– acceptor interactions and π−π interactions. The HOMO and LUMO were simulated by determinate the transition state and energy band gap. Vibrational analysis shows that the band in 3185 cm-1 and shifting of band to lower wave number clearly indicates strong intermolecular interactions between chitosan and PVP. When the PVP oligomers is blended with chitosan, this absorption signal, which is assigned to the stretching vibration of a C=O group in the pyrrolidone ring, tends to shift to a position of somewhat lower frequency.

Molecular Modeling Descriptors and Analytical Chemistry Data of Antihistaminic Drugs

The relationships between experimental and computational descriptors of antihistamine drugs were studied using principal component analysis (PCA). Empirical data came from UV and IR spectroscopic measurements. Nonempirical data, such as structural molecular descriptors and chromatographic data, were obtained from HyperChem software. Another objective was to test whether the parameters used as independent variables (nonempirical and empirical-spectroscopic) could lead to attaining classification similar to that developed on the basis of the chromatographic parameters. To arrive at the answer to the question, a matrix of 18 × 49 data, including HPLC and UV and IR spectroscopic data, together with molecular modeling studies, was evaluated by the PCA method. The obtained clusters of drugs were consistent with the drugs' chemical structure classification. Moreover, the PCA method applied to the HPLC retention data and structural descriptors allowed for classification of the drugs according to their pharmacological properties; hence it may potentially help limit the number of biological assays in the search for new drugs.

IN SILICO PREDICTION OF MELTING POINTS OF IONIC LIQUIDS BY USING MULTILAYER PERCEPTRON NEURAL NETWORKS

Quantitative structure–property relationship (QSPR) was used to predict melting points of 62 ionic liquids (ILs), which include ammonium, pyrrolidiniu, imidazolium, pyridiniu, piperidiniu, phosphonium ionic liquid salts. The structures of ionic liquids were optimized by Hyperchem software and MOPAC program, and stepwise multiple linear regression method was applied to select the relevant structural descriptors. The predicting models correlating selected descriptors and melting points were set up using multiple linear regressions (MLR) and multilayer perceptron neural network (MLP NN), separately. The obtained linear and nonlinear QSPR models were validated by internal and external test sets. According to the obtained results, the correlation coefficients between predicted and experimental melting points for training, test and validation sets were; 0.91, 0.86 and 0.79 for MLR model. These values for MLP NN model were; 0.97, 0.96 and 0.85, respectively. The results of this study revealed the high applicability of QSPR approach to melting point prediction of ILs.