scholarly journals Dynamic intermolecular interactions through hydrogen bonding of water promote heat conduction in hydrogels

2020 ◽  
Vol 7 (11) ◽  
pp. 2936-2943 ◽  
Author(s):  
Jiawei Zhou ◽  
Shaoting Lin ◽  
Hongxia Zeng ◽  
Ji Liu ◽  
Buxuan Li ◽  
...  

Dynamic intermolecular forces through hydrogen bonding between water and polymer chains are shown to enhance thermal transport in soft materials.

CrystEngComm ◽  
2019 ◽  
Vol 21 (35) ◽  
pp. 5206-5210 ◽  
Author(s):  
Tania Hill ◽  
Rudolph M. Erasmus ◽  
Demetrius C. Levendis ◽  
Andreas Lemmerer

Coloured three component complexes are made using both charge transfer and hydrogen bonding intermolecular interactions.


Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4125
Author(s):  
Viraj De Silva ◽  
Boris B. Averkiev ◽  
Abhijeet S. Sinha ◽  
Christer B. Aakeröy

In order to explore how specific atom-to-atom replacements change the electrostatic potentials on 1,3,4-chalcogenadiazole derivatives, and to deliberately alter the balance between intermolecular interactions, four target molecules were synthesized and characterized. DFT calculations indicated that the atom-to-atom substitution of Br with I, and S with Se enhanced the σ-hole potentials, thus increasing the structure directing ability of halogen bonds and chalcogen bonds as compared to intermolecular hydrogen bonding. The delicate balance between these intermolecular forces was further underlined by the formation of two polymorphs of 5-(4-iodophenyl)-1,3,4-thiadiazol-2-amine; Form I displayed all three interactions while Form II only showed hydrogen and chalcogen bonding. The results emphasize that the deliberate alterations of the electrostatic potential on polarizable atoms can cause specific and deliberate changes to the main synthons and subsequent assemblies in the structures of this family of compounds.


2001 ◽  
Vol 66 (8) ◽  
pp. 1208-1218 ◽  
Author(s):  
Guofeng Li ◽  
Mira Josowicz ◽  
Jiří Janata

Structural and electronic transitions in poly(thiophenyleneiminophenylene), usually referred to as poly(phenylenesulfidephenyleneamine) (PPSA) upon electrochemical doping with LiClO4 have been investigated. The unusual electrochemical behavior of PPSA indicates that the dopant anions are bound in two energetically different sites. In the so-called "binding site", the ClO4- anion is Coulombically attracted to the positively charged S or N sites on one chain and simultaneously hydrogen-bonded with the N-H group on a neighboring polymer chain. This strong interaction causes a re-organization of the polymer chains, resulting in the formation of a networked structure linked together by these ClO4- Coulombic/hydrogen bonding "bridges". However, in the "non-binding site", the ClO4- anion is very weakly bound, involves only the electrostatic interaction and can be reversibly exchanged when the doped polymer is reduced. In the repeated cycling, the continuous and alternating influx and expulsion of ClO4- ions serves as a self-organizing process for such networked structures, giving rise to a diminishing number of available "non-binding" sites. The occurrence of these ordered structures has a major impact on the electrochemical activity and the morphology of the doped polymer. Also due to stabilization of the dopant ions, the doped polymer can be kept in a stable and desirable oxidation state, thus both work function and conductivity of the polymer can be electrochemically controlled.


2006 ◽  
Vol 84 (7) ◽  
pp. 949-959 ◽  
Author(s):  
Letitia M Gruia ◽  
Fernande D Rochon ◽  
André L Beauchamp

The trischelate [Cr(H2biim)3](NO3)3 complex of 2,2′-biimidazole (H2biim) was obtained by reacting CrCl3·3THF with [Ag(H2biim)](NO3) in methanol. In the solvent-free material, each ligand forms two N-H···O bonds to a nitrate ion and generates locally neutral [Cr(H2biim)3](NO3)3 units. A methanol solvate was also obtained in which intermolecular interactions involve optimal use of the hydrogen-bonding ability of the [Cr(H2biim)3]3+ cations, NO3– anions, and methanol molecules. In both cases, there is no long-range regular organization of the complex units. Deprotonation of [Cr(H2biim)3](NO3)3 with NaOCH3 yielded neutral Cr(Hbiim)3. Its powder pattern is similar to that of Ru(Hbiim)3, suggesting that it also consists of mutually perpendicular interlocked honeycomb sheets. Recrystallization by slow diffusion of diisopropyl ether into a methanol solution yielded a porous material of composition Cr(Hbiim)3·2.6C6H14O in which superposed honeycomb sheets create infinite channels (~13 Å diameter) filled with disordered solvent molecules. A totally different structure is adopted by the solvate Cr(Hbiim)3·C6H6·2H2O, where the benzene molecule is encapsulated in a cavity created by five complex molecules.Key words: chromium, biimidazole, supramolecular, crystal structure, hydrogen bonding.


IUCrData ◽  
2018 ◽  
Vol 3 (11) ◽  
Author(s):  
Moaz M. Abdou ◽  
Magdalini Matziari ◽  
Paul M. O'Neill ◽  
Eric Amigues ◽  
Ruixue Zhou ◽  
...  

The title compound, C10H12O3, crystallizes in the orthorhombicP212121space group. The structure contains a phenolic group with the OH being coplanar with the phenyl ring. The structure exhibits significant hydrogen bonding between the O—H group of one molecule and the CO group of an adjacent one. These O—H...O=C interactions form chains of molecules parallel to thebaxis. No π–π or C—H...π intermolecular interactions are observed.


Author(s):  
Suresh Suganya ◽  
Kandasamy Saravanan ◽  
Ramakrishnan Jaganathan ◽  
Poomani Kumaradhas

The intermolecular interactions and salt formation of acridine with 4-aminosalicylic acid, 5-chlorosalicylic acid and hippuric acid were investigated. The salts obtained were acridin-1-ium 4-aminosalicylate (4-amino-2-hydroxybenzoate), C13H10N+·C7H6NO3 − (I), acridin-1-ium 5-chlorosalicylate (5-chloro-2-hydroxybenzoate), C13H10N+·C7H4ClO3 − (II), and acridin-1-ium hippurate (2-benzamidoacetate) monohydrate, C13H10N+·C9H8NO3 −·H2O (III). Acridine is involved in strong intermolecular interactions with the hydroxy group of the three acids, enabling it to form supramolecular assemblies. Hirshfeld surfaces, fingerprint plots and enrichment ratios were generated and investigated, and the intermolecular interactions were analyzed, revealing their quantitative contributions in the crystal packing of salts I, II and III. A quantum theory of atoms in molecules (QTAIM) analysis shows the charge–density distribution of the intermolecular interactions. The isosurfaces of the noncovalent interactions were studied, which allows visualization of where the hydrogen-bonding and dispersion interactions contribute within the crystal.


2006 ◽  
Vol 84 (5) ◽  
pp. 804-811 ◽  
Author(s):  
David Wolstenholme ◽  
Manuel AS Aquino ◽  
T Stanley Cameron ◽  
Joseph D Ferrara ◽  
Katherine N Robertson

The tetraphenylphosphonium squarate salt crystallizes with a number of diverse interactions, which all have the potential to be classified as hydrogen bonds. The squarate anions are found as dimers linked by O-H···O interactions. The multipole refinement of the tetraphenylphosphonium squarate was performed using the Hansen–Coppens model followed by topological analysis of its intermolecular interactions. A total of 28 interactions were found among the symmetry related molecules, which include a number of C-H···Cπ, C-H···O, and C-H···H-C interactions, along with the O-H···O interaction. With the criteria for hydrogen bonding proposed by Popelier and Koch, it is possible to determine which of these interactions are hydrogen bonds and which are van der Waals interactions. Both linear and exponentially dependent correlations can be seen for the properties of the bond critical points involving the intermolecular interactions that fulfill these criteria. All this leads to a better understanding of the role that hydrogen bonds play in the formation of small organic compounds.Key words: electron density, multiple refinement, hydrogen bonds.


Author(s):  
Mariem M. Abrougui ◽  
Modesto T. Lopez-Lopez ◽  
Juan D. G. Duran

Magnetic gels (ferrogels) are heterogeneous systems structured at the nanoscale that contains magnetic particles dispersed in three-dimensional networks of polymer chains. In the present work, the magnetic particles were synthesized with a core–shell structure, consisting of sepiolite particles covered by magnetite nanoparticles. These composite particles had a rod-like shape with a high aspect ratio. The obtained sepiolite–magnetite particles showed a high enough susceptibility and saturation magnetization. The magneto-rheological (MR) properties, and the intensity of the MR effect, of aqueous suspensions of the synthesized particles were studied. The particles, functionalized by adsorption of alginate molecules, were imbedded in alginate hydrogels to get homogeneous soft materials. The particles were linked to the polymer chains as the knots in a network and dominated in a great extent the mechanical properties of the materials. After determining the optimal compositions of the ferrogels, their viscoelastic properties were measured in the absence/presence of magnetic fields. The results pointed out that the MR effect provided by the clay–magnetite particles was considerably more intense than those achieved in ferrogels that contain spherical magnetic microparticles. Therefore, the imbedding of rod-shaped magnetic particles in hydrogels allows controlling the mechanical properties in a wider range than in conventional ferrogels. This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.


2003 ◽  
Vol 59 (2) ◽  
pp. 263-276 ◽  
Author(s):  
Manuel Melguizo ◽  
Antonio Quesada ◽  
John N. Low ◽  
Christopher Glidewell

The molecular and supramolecular structures of eight N 4-substituted 2,4-diamino-6-benzyloxy-5-nitrosopyrimidines are discussed, along with one analogue containing no nitroso substituent. The nitroso derivatives all exhibit polarized molecular-electronic structures leading to extensive charge-assisted hydrogen bonding between the molecules. The intermolecular interactions include hard hydrogen bonds of N—H...O and N—H...N types, together with O—H...O and O—H...N types in the monohydrate of 2-amino-6-benzyloxy-4-piperidino-5-nitrosopyrimidine, soft hydrogen bonds of C—H...O, C—H...π(arene) and N—H...π(arene) types and aromatic π...π stacking interactions. The predominant supramolecular structure types take the form of chains and sheets, but no two of the structures determined here exhibit the same combination of hydrogen-bond types.


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