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    Wyświetlanie 1-15 z 15
    Tytuł:
    A molecular dynamics study of the influence of chemical reduction on the structure of amorphous Germania
    Autorzy:
    Witkowska, A.
    Murawski, L.
    Bergmański, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1963001.pdf
    Data publikacji:
    2002
    Wydawca:
    Politechnika Gdańska
    Tematy:
    oxide glasses
    hydrogen reduction
    molecular dynamics
    structural modelling
    Opis:
    The contribution is dedicated to the molecular dynamics (MD) study of the structure of reduced germania glass of composition 1Ge 1GeO2. The work is inspired by a recent report on the formation of Ge clusters in hydrogen reduced germanate glasses containing oxides of heavy metals. The MD simulations have been performed in the microcanonical (NVE) ensemble, using a simple two-body Born-Mayer-Huggins interaction potential. A tendency of germanium atoms to agglomeration into clusters, observed in the present calculations, is compared with an analogous tendency of Bi and Pb atoms, observed previously in the xBi (1-x)GeO2 and xPb (1-x)GeO2 systems. The differences in the short and medium-range order in GeO2 system between the 1Ge 1GeO2 and GeO2 glasses are discussed.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 2; 273-281
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Betainy jako akceptory protonu
    Betaines as proton-acceptors
    Autorzy:
    Dega-Szafran, Z.
    Szafran, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/172795.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    betainy
    kompleksy z wiązaniem wodorowym
    struktura
    betaines
    hydrogen bonded complexes
    molecular structure
    Opis:
    Ammonium alkanoates (ammonioalkanocarboxylates) are zwitterions (or inner salts, or betaines), because they possess formally charged ammonium and carboxylate groups separated by one or more sp3 carbon atoms. The chemistry of betaines has become a subject of particular interest due to their applications in biological research, especially with regard to their important role in aminoacid synthesis as methyl transfer agents. The crystals of many betaine complexes display interesting physical properties, exhibiting phase transitions with ferroelectric, antiferroelctric and ferroelastic behavior. Betaines containing a hydrophobic chain in the range of 8–20 carbon atoms show the unique properties characteristic for amphoteric surfactants and their current industrial application is in toiletries and personal care products. The conformational structure of zwitterionic molecules depends on several factors. The electrostatic attraction between two charged groups depends strongly on arm flexibility (energy differences between rotational trans and gauche isomers), bulkiness and hydration of charged groups preventing their close approach, solvent and arm electrical properties which control electrostatic attraction between two opposite charged groups, and polarization of solvent around the molecule caused by the dielectric discontinuity between solvent and solute interior (image charge effect). Electrostatic interaction is the common determinant and probably the most important element in structure-reactivity correlation in organic and biological systems. On the other hand, organic compounds are thought to be pure even though they may be a mixture of conformational isomers. This is because the isomers covert rapidly with each other at room temperature and their individual reactivates are little known. Occasionally the conformers may be stabilized in the crystallographic matrixes of polymorphic structures. This article describes structures of seven groups of aliphatic, aromatic and alicyclic betaines and numbers of their new hydrogen-bonded complexes with mineral and organic acids.
    Źródło:
    Wiadomości Chemiczne; 2017, 71, 7-8; 609-628
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Charakterystyka oddziaływań międzycząsteczkowych : od dimerów do modeli mikrosolwatacyjnych
    Characterization of intermolecular interactions : from dimers to microsolvation models
    Autorzy:
    Panek, Jarosław J.
    Jezierska, Aneta
    Powiązania:
    https://bibliotekanauki.pl/articles/172152.pdf
    Data publikacji:
    2020
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    SAPT
    międzycząsteczkowe wiązania wodorowe
    mikrosolwatacja
    dimery
    trimery
    asocjaty molekularne
    intermolecular hydrogen bond
    microsolvation
    dimers
    trimers
    molecular associates
    Opis:
    Intermodular interactions play an important role in many processes at the molecular level. In the contemporary science, there is a growing interest concerning the characteristics of such interactions. Therefore, the computational chemistry can provide answers to many questions, which could not be answered using experimental methods. The Symmetry-Adapted Perturbation Theory (SAPT) method was applied to characterize the energy partitioning in dimers, trimers and microsolvation models. The investigated complexes belong to various classes of compounds, e.g. • dimers of: NH3 ˑˑˑHX, HF-pyridine, cycloalkanes, hypohalous acids; • trimers of: NH3 ˑˑˑNH3ˑˑˑHF or NH3ˑˑˑHFˑˑˑHF; • microsolvation models (biotin - water molecules). The current study summarizes recent years of our research devoted to the intermolecular interactions.
    Źródło:
    Wiadomości Chemiczne; 2020, 74, 9-10; 645-662
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Chemical regulation of photorespiratory hydrogen peroxide-induced cell death in catalase deficient (cat2) Arabidopsis plants
    Autorzy:
    Kerchev, P.
    Denecker, J.
    Muhlenbock, P.
    Van Breusegem, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/80515.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    conference
    photorespiration
    hydrogen peroxide
    cell death
    catalase
    Arabidopsis
    molecular structure
    microarray
    Źródło:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 2
    0860-7796
    Pojawia się w:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Conformational Stability, TGA, and Molecular Docking Investigations of p-Coumaric Acid with Special Relevance to Anti-Cancer and Antibacterial Activity
    Autorzy:
    Sathish, M.
    Meenakshi, G.
    Xavier, S.
    Sebastian, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1032309.pdf
    Data publikacji:
    2017-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    conformational analysis
    molecular geometry
    molecular docking
    p-coumaric acid
    hydrogen bonding
    TGA
    Opis:
    In this work an attempt is made to analysis of the possible different conformers of p-coumaric acid (PCA) by using density functional method. The total energy of four possible conformers were calculated by using B3LYP/6-311G(d,p) method. Computational result identifies that the most stable conformer of PCA is C2. The formation of inter- and intra-molecular hydrogen bonding between -OH and -COOH group gave the evidence for dimer formation for PCA molecule. The highest occupied-lowest unoccupied molecular orbital analysis shows that the negative electrostatic region situated over the -COOH group and positive electrostatic potential region are localized on ring system and all hydrogen. The PCA has been screened to anti-microbial activity and found to exhibit anti-bacterial effects. Molecular docking results suggest that PCA may exhibit inhibitory activity against lung cancer protein and may act as potential against lung cancer.
    Źródło:
    Acta Physica Polonica A; 2017, 131, 6; 1512-1518
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Efekt kooperatywności oddziaływań iekowalencyjnych w wybranych układach molekularnych stabilizowanych wiązaniami wodorowymi i halogenowymi
    Cooperativity effect in noncovalent interactions of selected molecular complexes stabilised by hydrogen and halogen bonds
    Autorzy:
    Domagała, Małgorzata
    Dominikowska, Justyna
    Palusiak, Marcin
    Powiązania:
    https://bibliotekanauki.pl/articles/172440.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    wiązanie halogenowe
    wiązanie wodorowe
    energia oddziaływania
    efekt kooperatywny
    modelowanie molekularne
    halogen bond
    hydrogen bond
    interaction energy
    cooperativity effect
    molecular modelling
    Opis:
    Among various so-called weak interactions, a halogen bond [8 and references therein] is currently probably one of more explored by researchers. This is due to the fact that it has several properties in common with the hydrogen bonding, and thus, similarly as already well characterised H-bond, it may have a crucial role in different physical, chemical, and biological processes. This bond is formed due to stabilising interactions between a region of positive charge located on a surface of the halogen atom and the other atomic center possessing the electron charge surplus (e.g. a lone pair) [8]. The region of positive charge appears on the halogen atom surface due to deformation of its electron cloud resulting in its ellipsoidal shape with the short axis opposite the covalent bond and the long axis in the perpendicular direction [11]. This results in a particular distribution of local charges on the atomic surface, as shown in Figure 1. As a consequence the halogen atom may exhibit a dual character, acting as either electron charge donor or acceptor, depending on the type of interaction and the direction of the appearing interactomic contact. A good example of such situation is shown in Figure 2. Thus, one may consider the situation when two interactions are formed simultaneously and the halogen atom acts as an electron charge donor and acceptor at the same time. For such situation the synergism of both interactions may strengthen complexation. In order to analyze that case, various representative complexes were investigated [13, 17, 18, 20, 21] by means of many-body interaction approach [5, 6]. In general, it appears that as distinct to hydrogen bond [2–4], the synergism is rather weak, with some exceptions for iodine atom due to stronger halogen bonds formed by that atomic centre [13, 17, 18]. In the case of halo-amine tetramers [21] the additional stabilising effect derived from back bonding of π type was found – for the first time for a halogen bond.
    Źródło:
    Wiadomości Chemiczne; 2019, 73, 1-2; 33-52
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of oxidation on the wetting of coal surfaces by water: experimental and molecular dynamics simulation studies
    Autorzy:
    Li, E.
    Lu, Y.
    Cheng, F.
    Wang, X.
    Miller, J. D.
    Powiązania:
    https://bibliotekanauki.pl/articles/109792.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    wettability
    oxidation
    molecular dynamics simulation
    hydrogen bonding
    contact angles
    coal surfaces
    Opis:
    The wettability of coal surfaces by water continues to be one of the key factors which determines the success of coal flotation. Consequently, oxidation of coal surfaces is a fundamental issue of interest. In this work, the effect of oxidation on the wetting of coal surfaces and the interaction between water molecules and oxygen-containing sites at the coal surface was investigated based on advancing/receding contact angle measurements and molecular dynamics simulations. For the simulation studies, a flat coal surface was constructed with the assistance of the molecular repulsion between graphite surfaces and the assembly of Wiser coal molecules. Our results indicated that the simulated advancing and receding contact angles were very similar, and both of them decreased, as expected, with an increase of hydroxyl sites at the coal surface. The good agreement between the simulated advancing/receding contact angles and the experimental receding contact angle values suggested that the configuration of the systems and the set of parameters for the simulation were appropriate. The spreading of water is mainly due to the hydrogen bonds formed between the interfacial water molecules and the hydroxyl sites at the coal surface. The hydroxyl groups show stronger hydration capacity than other oxygen-containing groups according to the calculated hydrogen bonds and interaction energies.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1039-1051
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of Temperature on the Properties of Cellulose Iβ based on Molecular Dynamics Simulations
    Autorzy:
    Huang, Shuang
    Wu, Xin
    Li, Peixing
    Powiązania:
    https://bibliotekanauki.pl/articles/2056296.pdf
    Data publikacji:
    2021
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
    Tematy:
    cellulose Iβ
    molecular dynamics simulation
    Mulliken population
    movement of chain
    hydrogen bond
    Opis:
    Natural plants, such as cotton and linen, are rich in cellulose Iβ. The properties of cellulose Iβ under different temperatures was studied using molecular dynamics simulations. Firstly, the crystal of cellulose Iβ was built. To verify the model, the X-ray fibre diffraction and thermal expansion coefficients were calculated, which were found to agree with experimental results. Then the Mulliken population of the bonds were computed and the movement of the centre chain and hydrogen bonds studied over the range 300-550 K using a PCFF force field. The results of the Mulliken population reveal the three steps of pyrolysis. The higher the temperature is, the more intensely the movement of the centre chain is. However, the impact of temperature on the movement of the centre chain is not obvious. From 300 K to 550 K, the total number of hydrogen bonds decreased by only 20%. Moreocer, the rupture of intrachain hydrogen bonds and the formation of interchain hydrogen bonds at 400 K~450 K temperature occurred.
    Źródło:
    Fibres & Textiles in Eastern Europe; 2021, 6 (150); 32--36
    1230-3666
    2300-7354
    Pojawia się w:
    Fibres & Textiles in Eastern Europe
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Molecular mechanism of chloroplastic H2O2-mediated stress response in Arabidopsis
    Autorzy:
    Maruta, T.
    Noshi, M.
    Toida, E.
    Tamoi, M.
    Yamato, K.
    Sawa, Y.
    Ishikawa, T.
    Shigeoka, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/80030.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    conference
    hydrogen peroxide
    molecular mechanism
    stress response
    thylakoid membrane
    ascorbate peroxidase
    Arabidopsis
    plant
    photooxidative stress
    oxidative stress
    salicylic acid
    Źródło:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 2
    0860-7796
    Pojawia się w:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Molowa entropia orientacyjna i struktura cieczy zasocjowanych
    Molar orientation entropy and structure of the self-associated liquids
    Autorzy:
    Jadżyn, J.
    Świergiel, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/172403.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    dipole molekularne
    przenikalność statyczna
    entropia orientacyjna
    ciecz
    wiązania wodorowe
    przejście fazowe ciecz izotropowa-nematyk
    molecular dipoles
    static permittivity
    orientation entropy
    liquids
    hydrogen bonds
    isotropic liquids to nematic phase transition
    Opis:
    Research on the structural effects of intermolecular interactions not only brings us closer to a better understanding the macroscopic properties of liquids, but also allows one to modify these properties. Intermolecular dipolar couplings and hydrogen bonds are the most common interactions in liquids leading to formation of multimolecular entities with various structures. The natural rival of these interactions is the thermal agitation of molecules (kT), which aims to destroy the emerging structures. In this paper we present an experimental method to estimate the way of molecular self-assembly resulting from the simultaneous action of kT and intermolecular interactions. The method is based on the study of dipolar orientation effects induced by an applied electric field. As an experimental source of the information on these effects is temperature derivative of the static permittivity of tested liquid. That derivative is proportional to the liquid entropy change due to the ordering action of the electric field on the molecular dipoles. Here, we present the experimental results on temperature dependence of the static permittivity and increment of the orientation entropy of liquids where the self-association process realizes with two ways: dipolar couplings and hydrogen-bonds.
    Źródło:
    Wiadomości Chemiczne; 2017, 71, 7-8; 517-532
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Priming through H2O2-mediated signalling in Arabidopsis thaliana
    Autorzy:
    Balazadeh, S.
    Shahnejat-Bushehri, S.
    Muller-Rober, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/80697.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    conference
    molecular mechanism
    hydrogen peroxide
    stress condition
    transcription factor
    Arabidopsis thaliana
    signalling
    Źródło:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 2
    0860-7796
    Pojawia się w:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Properties of water hydrating the galactolipid and phospholipid bilayers: a molecular dynamics simulation study
    Autorzy:
    Markiewicz, Michał
    Baczyński, Krzysztof
    Pasenkiewicz-Gierula, Marta
    Powiązania:
    https://bibliotekanauki.pl/articles/1038986.pdf
    Data publikacji:
    2015
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    molecular modelling
    hydrogen bonds
    water diffusion
    water dipole orientation
    inter-lamellar water
    Opis:
    Molecular dynamics simulations of 1,2-di-O-acyl-3-O-β-D-galactopyranosyl-sn-glycerol (MGDG) and 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) bilayers were carried out to compare the effect of the lipid head group's chemical structure on the dynamics and orientational order of the water molecules hydrating the bilayer. The effect of the bilayers on the diffusion of water is strong for the neighbouring water molecules i.e., those located not further than 4 Å from any bilayer atom. This is because the neighbouring water molecules are predominantly hydrogen bonded to the lipid oxygen atoms and their mobility is limited to a confined spatial volume. The choline group of DOPC and the galactose group of MGDG affect water diffusion less than the polar groups located deeper in the bilayer interface, and similarly. The latter is an unexpected result since interactions of water with these groups have a vastly different origin. The least affected by the bilayer lipids is the lateral diffusion of unbound water in the bilayer plane (x,y-plane) - it is because the diffusion is not confined by the periodic boundary conditions, whereas that perpendicular to the plane is. Interactions of water molecules with lipid groups also enforce certain orientations of water dipole moments. The profile of an average water orientation along the bilayer normal for the MGDG bilayer differs from that for the DOPC bilayer. In the DOPC bilayer, the ordering effect of the lipid head groups extends further into the water phase than in the MGDG bilayer, whereas inside the bilayer/water interface, ordering of the water dipoles in the MGDG bilayer is higher. It is possible that differences in the profiles of an average water orientation across the bilayer in the DOPC and MGDG bilayers are responsible for differences in the lateral pressure profiles of these bilayers.
    Źródło:
    Acta Biochimica Polonica; 2015, 62, 3; 475-481
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Protective effects of molecular hydrogen on hepatotoxicity induced by sub-chronic exposure to chlorpyrifos in rats
    Autorzy:
    Xun, ZM.
    Xie, F.
    Zhao, PX.
    Liu, MY.
    Li, ZY.
    Song, JM.
    Kong, XM.
    Ma, XM.
    Li, XY.
    Powiązania:
    https://bibliotekanauki.pl/articles/2085965.pdf
    Data publikacji:
    2020
    Wydawca:
    Instytut Medycyny Wsi
    Tematy:
    oxidative stress
    hepatotoxicity
    chlorpyrifos
    molecular hydrogen
    mitochondrial pathway
    Opis:
    Introduction. Chlorpyrifos (CPF) is a organophosphate insecticide widely used in agriculture with attendant adverse health outcomes. Chronic exposure to CPF induces oxidative stress and elicits harmful effects, including hepatic dysfunction. Molecular hydrogen has been identified as a novel antioxidant which could selectively scavenge hydroxyl radicals. Objective. The aim of this study was to determine whether the intake of hydrogen-rich water (HRW) could protect rats from hepatotoxicity caused by sub-chronic exposure to CPF. Materials and method. Rats were treated with hydrogen-rich water by oral intake for 8 weeks. Biochemical indicators of liver function, SOD and CAT activity, GSH and MDA levels were determined by the spectrophotometric method. Liver cell damage induced by CPF was evaluated by histopathological and electron microscopy analysis. PCR array analysis was performed to investigated the effects of molecular hydrogen on the regulation of oxidative stress related genes. Results. Both the hepatic function tests and histopathological analysis showed that the liver damage induced by CPF could be ameliorated by HRW intake. HRW intake also attenuated CPF induced oxidative stress, as evidenced by restored SOD activities and MDA levels. The results of PCR Array identified 12 oxidative stress-related genes differentially expressed after CPF exposure, 8 of chich, including the mitochondrial Sod2 gene, were significantly attenuated by HRW intake. The electron microscopy results indicated that the mitochondrial damage caused by CPF was alleviated after HRW treatment. Conclusions. The results obtained suggest that HRW intake can protect rats from CPF induced hepatotoxicity, and the oxidative stress signaling and the mitochondrial pathway may be involved in the protection of molecular hydrogen.
    Źródło:
    Annals of Agricultural and Environmental Medicine; 2020, 27, 3; 368-373
    1232-1966
    Pojawia się w:
    Annals of Agricultural and Environmental Medicine
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Struktura a nieelastyczne rozpraszanie neutronów przez kryształy molekularne z wiązaniami wodorowymi
    Structure and inelastic neutron scattering by the molecular crystals with the hydrogen bonds
    Autorzy:
    Rok, M.
    Bator, G.
    Sobczyk, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/171492.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    kompleksy molekularne
    wiązanie wodorowe
    struktura krystaliczna
    rozpraszanie neutronów
    dynamika cząsteczek w fazie stałej
    molecular complexes
    hydrogen bonds
    crystal structure
    neutron scattering
    molecular dynamics in the solid state
    Opis:
    The molecular crystals, which are built of organic or organic-inorganic molecules, are characterized by the weak intermolecular interactions. From the viewpoint of the potential applications in electronics or optoelectronics the electric properties of the crystals are essential. In turn these properties are related to their crystal structure as well as the dynamics of the molecules in the solid state. The existence of the hydrogen bonds in the crystal structures, conventional and unconventional, is crucial from the viewpoint of the electric properties of the crystals. The dynamics of methyl groups present in the structure can be a measure of the molecular interactions in the crystals. In this work the dynamical properties, first of all taking into account the research results concerning the neutron scattering, will be discussed. The neutron technique is very effective as regards the methyl group dynamics investigations. The relationship between a formation of the conventional and unconventional hydrogen bonds and a tunneling of the methyl groups at low temperature will be discussed. The method of the interpretation of the INS spectra will be described taking into account the theoretical model, the parameters of which are fitted to the experimental data. The examples will regard the following molecular crystals: p-N,N’-1,10-tetraacethyldiaminodurene (TADD) (Figs. 2 and 4), 2,3,5,6-tetramethylpyrazine with chloranilic acid (TMP·CLA) (Figs. 5, 6 and 7), 2,3,5,6- tetramethylpyrazine with bromanilic acid (TMP·BRA) (Figs. 5 and 6) and the crystal of 3,4,7,8-tetramethylphenantroline (Me4phen) and its complex with picric acid (Me4phen·PIC) (Figs. 8 and 9). In this paper we have shown that the surrounding of the methyl group and its interactions with the adjacent molecules has a stronger effect than the changes in the electronic charge density in the molecule.
    Źródło:
    Wiadomości Chemiczne; 2017, 71, 7-8; 533-557
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Właściwości czasowo-rozdzielcze słabych międzycząsteczkowych wiązań wodorowych C-H···F
    Time-resolved properties of intermolecular C-H···F hydrogen bonds
    Autorzy:
    Polańska, Marta
    Rodziewicz, Paweł
    Powiązania:
    https://bibliotekanauki.pl/articles/27310029.pdf
    Data publikacji:
    2023
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    wiązanie wodorowe
    teoria funkcjonału gęstości
    dynamika molekularna Cara i Parrinello
    hydrogen bond
    density functional theory
    Car-Parrinello molecular dynamics
    Opis:
    The hydrogen bond is one of the most important and interesting phenomena in nature. In this publication we will shed light on the discovery of hydrogen bond and a time evolution of its definition in the last 100 years. Both structural and spectroscopic parameters of the hydrogen bond will be discussed. A special focus will be given to the latest IUPAC definition of the hydrogen bond and its consequences to scientific research. The main aim of this study is to highlight theoretical studies based on first principles calculations and molecular dynamics simulations which not only support experimental results but also provide parameters which are crucial to understand the nature of hydrogen bonds. Particular attention will be given to methods and theoretical ideas used in the computational studies of hydrogen bonds. Utilizing static DFT/ab initio calculations and molecular dynamics simulations enables comparison of different binding energies and studying time evolution of the hydrogen-bonded molecular system on the atomistic level. We will discuss time-resolved properties of weak intermolecular hydrogen bonds, using as an example C-H···F containing model systems, namely F3CH*(HF)n molecular complexes and (F3CH)2-4 aggregates.
    Źródło:
    Wiadomości Chemiczne; 2023, 77, 9-10; 899--919
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-15 z 15

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