10 results on '"*MOLECULAR orbitals"'
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2. Електронна структура основ ціанінових барвників у розчинах і плівках
- Author
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Павленко, О. Л., Гапонов, А. М., Лесюк, А. І., Пундик, І. П., Дмитренко, О. П., Куліш, М. П., Кобзар, П. Ю., Курдюков, B. В., and Качковський, О. Д.
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MATTER ,CYANINES ,MOLECULAR orbitals ,ABSORPTION spectra ,LIGHT absorption ,SOLVATOCHROMISM - Abstract
Copyright of Nanosistemi, Nanomateriali, Nanotehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
3. Modeling of orthosilicate and methanesulfonic acid clusters in aqueous solution
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A.H. Mandryka, O.O. Pasenko, V.H. Vereschak, and Y.S. Osokin
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orthosilicate acid ,methanesulfonic acid ,clusters ,aqueous solution ,quantum chemical modeling ,binding energy ,hydrogen bonding ,Physics ,QC1-999 - Abstract
In the work using the quantum-chemical modeling method, the possibility of binding orthosilicate acid with different amounts of methanesulfonate anions was considered. It was demonstrated that methanesulfonic acid forms two hydrogen bonds with a molecule of orthosilicate acid, regardless of the conformation of the cluster itself. According to the results of calculations of energy parameters of systems and frontier molecular orbitals, it was established that the most stable cluster of orthosilicate acid with methanesulfonate anion is [H4SiO4 · 4CH3SO3–]. It was also established that the formation of an eight-membered cycle (S–O···H–O–Si–O–H···O) and (S–O···H –O–Si–O···H–С). Furthermore, it was established that there is no significant dependence of the effective charge on the silicon atom on the number of methanesulfonate anions in the inner sphere. Thus, it is theoretically demonstrated that the methanesulfonate anion is able to stabilize orthosilicate acid and reduce the possibility of its dimerization.
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- 2023
- Full Text
- View/download PDF
4. Перебудова електронної структури плівок триптофану за його взаємодії з наночастинками Ag, вкритими поліетиленгліколем.
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Гапонов, А. М., Павленко, О. П., Куліш, М. П., Дмитренко, О. П., Лесюк, А. І., Онанко, А. П., Оберніхіна, Н. В., and Неймаш, В. Б.
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ABSORPTION spectra ,SILVER nanoparticles ,OPTICAL spectra ,LIGHT absorption ,ELECTRONIC structure ,TRYPTOPHAN ,POLYETHYLENE glycol - Abstract
The optical absorption spectra of layered films based on silver nanoparticles coated with polyethylene glycol (PEG) and the amino acid tryptophan deposited by thermal vacuum sputtering are studied. Quantum-chemical calculations indicate the possibility of complex formation of amino acid with polymer chains. The structure of the complexes and the electronic structure, which affects the absorption spectra and is the result of the interaction of tryptophan with PEG, are characterized. [ABSTRACT FROM AUTHOR]
- Published
- 2023
5. TARGETED SEARCH OF SUBSTANCES AMONG A NUMBER OF 3 - ARYL (ARALKYL) XANTHINE DERIVATIVES HAVING ANTIRADICAL ACTIVITY WITH REGARD TO SUPEROXIDE RADICALS
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V. P. Ryzhenko, O. A. Ryzhov, S. V. Levich, I. F. Belenichev, and К. V. Aleksandrova
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Computer applications to medicine. Medical informatics ,R858-859.7 - Abstract
The aim of the research was to study the basic descriptors of frontier molecular orbitals of 3- aryl (aralkyl) xanthine using semi-empirical quantum- chemical methods and substantiate their impact on the manifestation of anti-radical activity. Comparison of received data and calculated descriptors values revealed linear dependence of anti-radical activity on the highest occupied and lowest unoccupied molecular orbitals energy values.
- Published
- 2016
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- View/download PDF
6. QUANTUM-CHEMICAL CHARACTERIZATION OF THE NEW [1,2,4]TRIAZOLO[1,5-А]PYRIMIDINE DERIVATIVES WITH BIOLOGICAL ACTIVITY
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Оlena, Bondar, Vasilenko Kateryna, Мakei Oleksandr, and Іryna, Kurmakova
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quantum-chemical descriptors ,correlation ,pharmacological activities ,[1,2,4]triazolo[1,5-a]pyrimidine derivatives - Abstract
Purpose. To determine the quantum chemical characteristics of new derivatives of [1,2,4]triazolo[1,5-a]-pyrimidine, which differ by substituents in the 3 position of the triazole cycle, and to establish the existing correlations “pharmacological activity – energy index” or “pharmacological activity - quantum chemical characteristics”. Methodology. The work used several computer programs, in particular, to calculate the energy performance of molecules - Hyperchem 7.0 (Hypercube, Inc.), to predict pharmacological activity – PASS- online, to assess the similarity of substances to registered pharmacological drugs – OSIRIS Property Explorer, for regression analysis – Microsoft Excel. Scientific novelty. The derivatives of [1,2,4]triazolo[1,5-a]pyrimidine studied in the work have not been previously studied, and the analysis to establish the correlation “pharmacological activity – energy index” was not performed. This is important for the further search for effective pharmacological drugs and the accumulation of theoretical data for the development of chemoinformatics. Conclusions. In silico studies of new derivatives of [1,2,4]triazolo[1,5-a]pyrimidine, as potentially pharmacologically active substances, was performed, which allowed establishing a high correlation between the probability of such pharmacological activity as Phosphodiesterase 10A inhibitor and some quantum chemical and energy characteristics of molecules. For [1,2,4]triazolo[1,5-a]pyrimidine derivatives, a high correlation (R2>0.90) of the probability of phosphodiesterase 10 inhibition (Phosphodiesterase 10A inhibitor) from such characteristics of the molecule as the total energy of the molecule was established. , the energy of atomization, the energy of isolated atoms, electronic energy of a chemical particle, energy of electrostatic interaction of atomic bodies, the energy of higher occupied and energy of lower unoccupied molecular orbitals.  
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- 2022
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7. Спектральні та квантово-хемічні дослідження взаємодії між фуллеренами та сквараїновими барвниками
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Павленко, О. Л., Брусенцов, В. А., Дмитренко, О. П., Куліш, М. П., Сендюк, В. А., Кобзар, П. Ю., Стрельчук, В. В., Сломінський, Ю. Л., Курдюков, B. В., Качковський, О. Д., and Простота, Я. О.
- Abstract
Copyright of Nanosistemi, Nanomateriali, Nanotehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2018
8. Електронна структура молекулярної системи фуллерену С60 з індопентаметинцианіновим барвником при стековій і ковалентній взаємодіях
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Зарицька, Г. М., Брусенцов, В. А., Павленко, О. Л., Дмитренко, О. П., Куліш, М. П., Качковський, О. Д., and Брікс, Ю. Л.
- Abstract
Copyright of Nanosistemi, Nanomateriali, Nanotehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
9. π-Електронна афінність азотистих основ нуклеїнових кислот
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Ніколаєв, Р.O.
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Біологія - Abstract
Досліджено відносне розташування фронтальних молекулярних орбіталей азотистих основ нуклеїнових кис лот, пов'язане з їх донорно-акцепторними властивостями як фундаментальною характеристикою спряжених молекул. Для кількісної квантово-хімічної оцінки донорно-акцепторних властивостей пуринових та піримідинових основ запропоновано індекс ϕ₀, за яким визначається зсув енергетичних рівнів відносно збалансованої системи. Азотисті основи розділені строго на дві групи: переважно донори — пуринові основи (ϕ₀ > 0,5) і переважно акцептори — піримідинові основи (ϕ₀ < 0,5). Енергії молекулярних орбіталей оцінені як експериментально, так і квантово-хімічно. Різниця показників ϕ₀ — здатність азотистих основ утворювати стабільні π-електронні комплекси. Исследовано относительное расположение фронтальных молекулярных орбиталей азотистых оснований нуклеиновых кислот, связанное с их донорно-акцепторными свойствами как фундаментальной характеристикой сопряженных молекул. Для количественной квантово-химической оценки донорно-акцепторных свойств пуриновых и пиримидиновых оснований предложен индекс ϕ₀, который позволяет определить сдвиг энергетических уровней относительно сбалансированной системы. Азотистые основания разделены строго на две группы: преимущественно доноры — пуриновые основания (ϕ₀ > 0,5) и преимущественно акцепторы — пиримидиновые основания (ϕ₀ < 0,5). Энергии молекулярных орбиталей были оценены как экспериментально, так и квантово-химически. Разница показателей Δϕ₀ — способность азотистых оснований образовывать стабильные π-электронные комплексы. The relative position of the frontier molecular orbitals (MO) of nucleic acid bases is investigated. It allows one to analyze their donor/acceptor properties in more details, and is a fundamental characteristic of conjugated molecules. Non-covalent interaction specify the spatial constitution of the chains of nucleic acids and their physical and chemical properties in the ground and excited states. Aromatic π-π stacking interactions are generally defined as the attractive interactions that occur between the π-clouds of aromatic systems in a parallel, face-to-face orientation, thus, it could be considered as an affinity of the conjugated molecules. They play a fundamental role in many aspects of chemistry and biochemistry, for example, in the fields molecular recognition self-assembly supramolecular chemistry, and general host-guest interactions. π-π-stacking in biology is of the integral to the structure and function of proteins, cofactors and substrates. Although this interaction is comparatively weak, it leads to large effects; so, DNA (deoxyribonucleic acid) structure being can be considered as an essential example. In such case in tricate scenarios, the π-π interaction is considered very often as some sort of “deus ex machine”, intervening in reactions, provides the additional stabilizing of helix complexes, and influencing the structure. Therefore, the energetic and structural features of these interactions can be estimated, which would be extremely useful in the modeling and understanding of many biological important phenomena. For the quantitative quantum-chemical evaluation of the donor-acceptor properties of the purine and pyrimidine bases, an index ϕ₀, indicating a shifting of the frontier levels in respect to the balanced system is proposed. The nucleic bases are strictly divided into two groups: predominantly, donors are purine bases (ϕ₀ > 0.5), and, preferably, acceptors are pyrimidine bases (ϕ₀ < 0.5). The energies of the MO were evaluated both experimentally and quantum-chemically. Difference of the indices Δϕ₀ is the ability of nitrogenous bases to form stable π-electronic complexes.
- Published
- 2019
10. Квантово-хімічні властивості диклофенаку
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Хімія - Abstract
Диклофенак натрію – нестероїдний протизапальний засіб, який широко використовується в медичній практиці. Вивчено квантово-хімічні властивості молекули диклофенаку. Оптимізацію геометрії молекули проведено методом РМ3 із використанням алгоритму Полака–Райбера. Визначено заряди атомів, загальний дипольний момент молекули, характеристики молекулярних орбіталей. Негативний електростатичний потенціал диклофенаку міститься на атомах оксигену та нітрогену. За енергетичними характеристиками ВЗМО і НВМО диклофенак є м'яким реагентом. Встановлені квантово-хімічні властивості диклофенаку можуть бути основою молекулярних механізмів його фармакологічної дії. Диклофенак натрия – нестероидное противовоспалительное средство, которое широко применяется в медицинской практике. Изучены квантово-химические свойства молекулы диклофенака. Оптимизация геометрии молекулы проведена методом РМ3 с использованием алгоритма Полака – Райбера. Определены заряды атомов, общий дипольный момент молекулы, характеристики молекулярных орбиталей. Негативный электростатический потенциал диклофенака находится на атомах оксигена и нитрогена. В соответствии с энергетическими характеристиками ВЗМО и НВМО диклофенак является мягким реагентом. Установленные квантово-химические свойства диклофенака могут быть основой молекулярных механизмов его фармакологической активности. Diclofenac sodium is a nonsteroidal antiinflammatory drug, which is widely used in medical practice. The studies of quantum-chemical properties of diclofenac are carried out. An optimization of the molecular geometry is made by the means of the PM3 method and Polak – Ribiere algorithm. The atomic charges, total dipole moment of the molecule, and characteristics of molecular orbitals are determined. The negative electrostatic potential of diclofenac is on oxygen and nitrogen atoms. Diclofenac is a soft reagent according to the HOMO-LUMO gap. The established quantum-chemical properties of diclofenac may become a basis of its molecular mechanisms of pharmacological action.
- Published
- 2016
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