scholarly journals Self-Assembly and Intermolecular Forces When Cellulose and Water Interact Using Molecular Modeling

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Ali Chami Khazraji ◽  
Sylvain Robert
Keyword(s):  
Hydrogen Bonds ◽  
Self Assembly ◽  
Intermolecular Forces ◽  
Electron Cloud ◽  
Water Molecules ◽  
Special Role ◽  
Structural Anisotropy ◽  
Intermolecular Hydrogen Bonds ◽  
Exothermic Reactions ◽  
Total Displacement

Cellulose chains are linear and aggregation occurs via both intra- and intermolecular hydrogen bonds. Cellulose has a strong affinity to itself and toward materials containing hydroxyls groups. Based on the preponderance of hydroxyl functional groups, cellulose is very reactive with water. At room temperature, cellulose chains will have at least a monomolecular layer of water associated to it. The formation of hydrogen bonds at the cellulose/water interface is shown to depend essentially on the adsorption site, for example, the equatorial hydroxyls or OH moieties pointing outward from the cellulose chains. The vdW forces also contribute significantly to the adsorption energy. They are a considerable cohesive energy into the cellulose network. At the surface of the cellulose chains, many intermolecular hydrogen bonds of the cellulose chains are lost. However, they are compensated by hydrogen bonds with water molecules. Electronic clouds can be distorted and create electrostatic dipoles. The large antibonding electron cloud that exists around the glucosidic bonds produces an induced polarization at the approach of water molecules. The electron cloud can be distorted and create an electrostatic dipole. It applies to the total displacement of the atoms within the material. Orbitals play a special role in reaction mechanism. Hydrophilic/hydrophobic nature of cellulose is based on its structural anisotropy. Cellulose-water interactions are exothermic reactions. These interactions may occur spontaneously and result in higher randomness of the system. They are denoted by a negative heat flow (heat is lost to the surroundings). Energy does not need to be inputted in order for cellulose-water interactions to occur.

scholarly journals SPECTRAL FEATURES AND HYDROGEN BOND STRUCTURE OF AQUEOUS SOLUTIONS OF ETHANOL

2021 ◽  
pp. 30-33
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bonds ◽  
Aqueous Solutions ◽  
Gaseous Medium ◽  
Water Molecules ◽  
Structural Reorganization ◽  
Intermolecular Hydrogen Bonds ◽  
Method Of Molecular Dynamics ◽  
Combined Use ◽  
Structure Of Aqueous Solutions

The aim of this work is develop an approach that makes it possible to study the spectral properties and structure of intermolecular hydrogen bonds in aqueous solutions of ethanol formed in systems whose existence in a gaseous medium or an isolated state is practically impossible. This approach bases on the combined use of infrared spectroscopy and molecular dynamics (MD) methods. An analysis give the structural reorganization of water molecules depending on the concentration of ethanol alcohol. It has been shown that the method of molecular dynamics with classical force fields makes it possible to explicitly take into account the molecules of the solvent and solute, and, thus, to investigate hydrogen bonds in the system and to interpret with the experimental data obtained by vibrational spectroscopy.

scholarly journals ISOLATION AND STRUCTURAL ELUCIDATION OF A NEW DEPSIDE OF LICHEN Everniopsis trulla

2021 ◽  
Vol 87 (2) ◽  
pp. 97-106
Author(s):  
Olivio Nino Castro ◽  
Jesús López Rodilla ◽  
Sofia Pombal ◽  
Francisca Sanz González ◽  
Julio Santiago Contreras
Keyword(s):  
Mass Spectrometry ◽  
Melting Point ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Spectroscopic Data ◽  
Intermolecular Forces ◽  
X Ray Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
Uv Visible

In this research, a new depside of the lichen Everniopsis trulla has been isolated. The extraction was carried out to 400 g of dry sample and ground with ethanol for 3 repetitions, then, it was fractionated by applying column chromatography with the CHCl3-MeOH system and purified by recrystallization with MeOH-Acetone (1: 1); Finally, white crystals in the form of needles (solid C) with a melting point of 198 ° C were obtained, whose structure was elucidated based on spectroscopic data (UV-Visible, IR, NMR-H1, NMR-C13, mass spectrometry and single crystal X-ray diffraction). According to the Science Finder databases, it is a new depside, called trullarin, and it is observed that molecular packing is influenced by both intramolecular and intermolecular forces. Intermolecular hydrogen bonds of O - H -O type binds neighboring molecules forming dimers.

scholarly journals Metallkomplexe mit Guanidinderivaten als Liganden: Kristallstrukturen von [Zn(cnge)2(SCN)2] · 2H2O und Zn(eoge)Br2 (enge = Cyanoguanidin; eoge = 1-Ethoxyiminomethylguanidin) / Metal Complexes with Guanidine Derivatives as Ligands: Crystal Structures of [Zn(cnge)2(SCN)2]·2H2O und Zn(eoge)Br2 (cnge = Cyanoguanidine; eoge = 1-Ethoxyim inom ethylguanidine)

1996 ◽  
Vol 51 (10) ◽  
pp. 1469-1472 ◽  
Author(s):  
Joachim Pickardt ◽  
Britta Kühn
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bonds ◽  
Metal Complexes ◽  
Crystal Structures ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Intermolecular Hydrogen Bonds ◽  
Crystal Water ◽  
Space Group ◽  
Guanidine Derivatives

Crystals of |Zn(cnge)2(SCN)2]-2H2O (1) were obtained by evaporation of an aqueous solution of Z n(SO4)·7H2O , KSCN, and cyanoguanidine. Crystals of Zn(eoge)Br2 (2) were obtained by reaction of ZnBr2 and cyanoguanidine in ethanol/water. Both compounds are monoclinic, space group C2/c, 1: Z = 4, a = 1919.6(7), b = 467.3(2), c = 1838.5(6) pm, β = 112.99(3)°, 2: Z = 8, a = 1799.5(6), b = 878.7(2), c = 1367.2(5) pm, β = 101.52(3)°. In 1 each Zn is bonded to two cyanoguanidine molecules and via the N atoms to two NCS groups. Intermolecular hydrogen bonds lead to chains along the a-axis, and these chains are again connected via hydrogen bonds to the two crystal water molecules. In the course of the formation of 2, the cyanoguanidine reacted with the ethanol to form 1-ethoxyiminomethylguanidine. This ligand forms chelate rings with the Zn atoms, which are tetrahedrally coordinated by the two imino N atoms of the ligand and by two bromine atoms.

Supramolecular Structure in the Cocrystal of 3, 5-Bispyridyl-1-H-1, 2, 4-Triazole and 4,4-Oxybis(Benzoic Acid)

2013 ◽  
Vol 781-784 ◽  
pp. 531-535
Author(s):  
Ting Li ◽  
Bing Li ◽  
Xiao Yan Chen ◽  
Jun Mei Wang ◽  
Lin Sun ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Benzoic Acid ◽  
Self Assembly ◽  
Cobalt Acetate ◽  
Intermolecular Hydrogen Bonds ◽  
Hydrogen Bond Interaction ◽  
Monoclinic System ◽  
One Dimensional ◽  
Carboxylate Groups ◽  
The One

A new cocrystal (3,4-Hbpt)-(H2oba) (3,4-Hbpt =3-(3-pyridyl)-5-(4-pyridyl)- 1-H-1,2,4-triazole and H2oba=4,4-oxybis (benzoic acid)), was prepared via self-assembly in the presence of cobalt acetate as template by hydrothermal reactions. The title complex was characterized by single-crystal X-ray diffraction, elemental analysis and IR spectroscopy. Structural analysis reveals that the complex belongs to monoclinic system, space group P21/c. The two carboxylate groups from H2oba are not deprotonated and form two kinds of strong intermolecular hydrogen bonds with 3,4-Hbpt, which linking the molecules into one-dimensional chains. Furthermore, the one-dimensional chains are connected by the hydrogen bond interaction to form two-dimensional lamellar structures. Intermolecular hydrogen bonds may be effective in the stabilization of the crystal structure.

Ornidazole hemihydrate

2007 ◽  
Vol 63 (11) ◽  
pp. o4204-o4204 ◽  
Author(s):  
Liping Deng ◽  
Wei Wang ◽  
Jianguo Lv
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Water Molecules ◽  
Asymmetric Unit ◽  
Intermolecular Hydrogen Bonds ◽  
Compound C ◽  
Independent Molecules

The asymmetric unit of the racemic title compound, C7H10ClN3O3·0.5H2O, has two independent molecules of ornidazole. The crystal structure is formed via intermolecular hydrogen bonds involving the water molecules.

scholarly journals Crystal structure ofcatena-poly[[[triaquastrontium]-di-μ2-glycinato] dibromide]

2015 ◽  
Vol 71 (7) ◽  
pp. 875-878 ◽  
Author(s):  
Palanisamy Revathi ◽  
Thangavelu Balakrishnan ◽  
Kandasamy Ramamurthi ◽  
Subbiah Thamotharan
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Alkaline Earth ◽  
Three Dimensional ◽  
Water Molecules ◽  
Intermolecular Hydrogen Bonds ◽  
Rotation Axes ◽  
Hydrogen Bonding Interactions ◽  
Carboxylate Groups ◽  
Glycine Molecule

In the title coordination polymer, {[Sr(C2H5NO2)2(H2O)3]Br2}n, the Sr2+ion and one of the water molecules are located on twofold rotation axes. The alkaline earth ion is nine-coordinated by three water O atoms and six O atoms of the carboxylate groups of four glycine ligands, two in a chelating mode and two in a monodentate mode. The glycine molecule exists in a zwitterionic form and bridges the cations into chains parallel to [001]. The Br−counter-anions are located between the chains. Intermolecular hydrogen bonds are formed between the amino and carboxylate groups of neighbouring glycine ligands, generating a head-to-tail sequence. Adjacent head-to-tail sequences are further interconnected by intermolecular N—H...Br hydrogen-bonding interactions into sheets parallel to (100). O—H...Br and O—H...O hydrogen bonds involving the coordinating water molecules are also present, consolidating the three-dimensional hydrogen-bonding network.

Hydrogen bonding in polyamino-polyalcohols: a monohydrated cocrystal of 1,3-diamino-5-azaniumyl-1,3,5-trideoxy-cis-inositol iodide and 1,3,5-triamino-1,3,5-trideoxy-cis-inositol

2014 ◽  
Vol 70 (4) ◽  
pp. 396-399 ◽  
Author(s):  
Christian Neis ◽  
Kaspar Hegetschweiler
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Chair Conformation ◽  
Structural Motif ◽  
Water Molecules ◽  
Intermolecular Hydrogen Bonds ◽  
Solvent Water ◽  
Entire Structure ◽  
Dimensional Network

In the title monohydrated cocrystal, namely 1,3-diamino-5-azaniumyl-1,3,5-trideoxy-cis-inositol iodide–1,3,5-triamino-1,3,5-trideoxy-cis-inositol–water (1/1/1), C6H16N3O3+·I−·C6H15N3O3·H2O, the neutral 1,3,5-triamino-1,3,5-trideoxy-cis-inositol (taci) molecule and the monoprotonated 1,3-diamino-5-azaniumyl-1,3,5-trideoxy-cis-inositol cation (Htaci+) both adopt a chair conformation, with the three O atoms in axial and the three N atoms in equatorial positions. The cation, but not the neutral taci unit, exhibits intramolecular O—H...O hydrogen bonding. The entire structure is stabilized by a complex three-dimensional network of intermolecular hydrogen bonds. The neutral taci entities and the Htaci+cations are each aligned into chains along [001]. In these chains, two O—H...N interactions generate a ten-membered ring as the predominant structural motif. The rings consist of vicinal 2-amino-1-hydroxyethylene units of neighbouring molecules, which are pairedviacentres of inversion. The chains are interconnected into undulating layers parallel to theacplane, and the layers are further held together by O—H...N hydrogen bonds and additional interactions with the iodide counter-anions and solvent water molecules.

Orthoamide und Iminiumsalze, LXX [1]. Zur Fixierung vonKohlendioxid mit organischen Basen (Teil 1) – Reaktionen von Diaminen mit Kohlendioxid / Orthoamides and Iminium Salts, LXX [1]. Capturing of Carbon Dioxide with Organic Bases (Part 1) – Reactions of Diamines with Carbon Dioxide

2011 ◽  
Vol 66 (2) ◽  
pp. 164-176
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Three Dimensional ◽  
Water Molecules ◽  
Intermolecular Hydrogen Bonds ◽  
Crystal Water ◽  
Organic Bases ◽  
Dimensional Network ◽  
Carbamate Group

The alkylammonium alkylcarbamates 2, 4a,b, 14 were prepared from the amines 1, 3a,b, 13 and CO2. The crystal structures of 2 and 4b show carbamate anions, which are connected by N-H···O hydrogen bonds to form centrosymmetric dimers. The zwitterionic carbamates 7a,b, 8a,b and 11 are formed in the reactions of the diamines 6a,b and 10 with CO2. The crystal structures of 7a and 8b show strong intermolecular hydrogen bonds involving water molecules, the ammonium and the carbamate groups. In these compounds the molecules are interconnected in an extended two- or three-dimensional network. Due to the absence of crystal water molecules, the structure of 11 contains intermolecular hydrogen bonds involving the ammonium and the carbamate group in double-stranded chains. The diamines 17a,b react with CO2 to give the zwitterionic carbamates 18a,b.

Triaquabis(4-formylbenzoato-κ2 O,O′)cadmium(II) trihydrate

2007 ◽  
Vol 63 (11) ◽  
pp. m2818-m2818
Author(s):  
Zhao-Peng Deng ◽  
Shan Gao ◽  
Li-Hua Huo ◽  
Hui Zhao
Keyword(s):  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Title Complex ◽  
Water Molecules ◽  
Supramolecular Network ◽  
Intermolecular Hydrogen Bonds ◽  
Hydrogen Bonded

The title complex, [Cd(C8H5O3)2(H2O)3]·3H2O, is a neutral mononuclear molecule consisting of a CdII atom chelated by two 4-formylbenzoate ligands and coordinated by three water molecules in a pentagonal–bipyramidal geometry. A three-dimensional hydrogen-bonded supramolecular network is formed by intermolecular hydrogen bonds.

1,2-Dimethyl-4-nitro-5-morpholinoimidazole and its hydrate: a case of a centrosymmetric–noncentrosymmetric ambiguity

2003 ◽  
Vol 59 (4) ◽  
pp. 487-491 ◽  
Author(s):  
Maciej Kubicki ◽  
Teresa Borowiak ◽  
Grzegorz Dutkiewicz ◽  
Stanisław Sobiak ◽  
Iwona Weidlich
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Van Der Waals Interactions ◽  
Water Molecules ◽  
Intermolecular Hydrogen Bonds ◽  
Strong Electron ◽  
Crystal Forms ◽  
Basic Character ◽  
Centrosymmetric Matrix ◽  
Water Hydrogen

The compound studied is 1,2-dimethyl-4-nitro-5-morpholinoimidazole (1) in its anhydrous (1) and hydrated [(1)·H2O] crystal forms. In spite of the strong electron-withdrawing effect of the nitro group, the unsubstituted N atom of the imidazole moiety retains its basic character and acts as an acceptor for intermolecular hydrogen bonds: either weak C—H...N bonds in (1) or strong O—H...N bonds, with the water molecules, in (1)·H2O. The packing in (1) is determined by weak C—H...N and C—H...O hydrogen bonds, van der Waals interactions and the stacking of imidazole fragments. The crystal structure of (1)·H2O is determined by strong O—H(water)...N3(imidazole) and O—H(water)...O(water) hydrogen bonds. This structure consists of a centrosymmetric `matrix' of imidazole derivative molecules and locally noncentrosymmetric arrays of hydrogen-bonded water molecules. Each of these arrays is strictly homodromic, i.e. it runs only in one direction: ...H—O...H—O...H—O... or ...O—H...O—H...O—H.... These homodromic domains are statistically distributed within the crystal.

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