The evolution of self-assemblies in the mixed system of oleic acid–diethylenetriamine based on the transformation of electrostatic interactions and hydrogen bonds

Soft Matter ◽  
2014 ◽  
Vol 10 (40) ◽  
pp. 8023-8030 ◽  
Author(s):  
Chengcheng Zhou ◽  
Xinhao Cheng ◽  
Oudi Zhao ◽  
Shuai Liu ◽  
Chenjiang Liu ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Hydrogen Bonds ◽  
Electrostatic Interactions ◽  
Mixed System

scholarly journals Cooperation/Competition between Halogen Bonds and Hydrogen Bonds in Complexes of 2,6-Diaminopyridines and X-CY3 (X = Cl, Br; Y = H, F)

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 766
Author(s):  
Barbara Bankiewicz ◽  
Marcin Palusiak
Keyword(s):  
Complex Formation ◽  
Hydrogen Bonds ◽  
Dft Calculations ◽  
Electrostatic Interactions ◽  
Dipole Moments ◽  
Main Role ◽  
Halogen Bonds ◽  
Topological Parameters ◽  
Leading Role ◽  
The Impact

The DFT calculations have been performed on a series of two-element complexes formed by substituted 2,6-diaminopyridine (R−PDA) and pyridine (R−Pyr) with X−CY3 molecules (where X = Cl, Br and Y = H, F). The primary aim of this study was to examine the intermolecular hydrogen and halogen bonds in the condition of their mutual coexistence. Symmetry/antisymmetry of the interrelation between three individual interactions is addressed. It appears that halogen bonds play the main role in the stabilization of the structures of the selected systems. However, the occurrence of one or two hydrogen bonds was associated with the favourable geometry of the complexes. Moreover, the impact of different substituent groups attached in the para position to the aromatic ring of the 2,6-diaminopyridine and pyridine on the character of the intermolecular hydrogen and halogen bonds was examined. The results indicate that the presence of electron-donating substituents strengthens the bonds. In turn, the presence of electron-withdrawing substituents reduces the strength of halogen bonds. Additionally, when hydrogen and halogen bonds lose their leading role in the complex formation, the nonspecific electrostatic interactions between dipole moments take their place. Analysis was based on geometric, energetic, and topological parameters of the studied systems.

α-Cellulose-Based Films: Effect of Sodium Lignosulfonate (SLS) Incorporation on Physicochemical and Antibacterial Performance

2021 ◽  
Author(s):  
Xinyu Lu ◽  
Han Que ◽  
Haoquan Guo ◽  
Chenrong Ding ◽  
Xu Liu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Tensile Strength ◽  
Hydrogen Bonds ◽  
Composite Film ◽  
Raw Materials ◽  
Mixed System ◽  
Cellulose Film ◽  
Sodium Lignosulfonate ◽  
Pure Cellulose ◽  
Antibacterial Performance

Abstract A homogeneous α-cellulose film was prepared by regeneration method from ZnCl2/CaCl2/cellulose mixed system and was further combined with sodium lignosulfonate (SLS) by crosslinking through interaction hydrogen bonds and “bridge linkages”. The physicochemical and antibacterial performance of films were all investigated and results showed that modified films exhibited stronger tensile strength, higher thermal stability, lower hydrophilic effect, better UV shielding as compared with those of pure cellulose film, and especially, better antibacterial ability derived from the presence of phenolic and sulfonate groups in SLS. This study proposed a simple and sustainable method for fabricating a multifunctional and environmentally friendly composite film by using two main lignocellulose resources as raw materials.

scholarly journals Crystal structure from X-ray powder diffraction data, DFT-D calculation, Hirshfeld surface analysis, and energy frameworks of (RS)-trichlormethiazide

2022 ◽  
Vol 78 (2) ◽  
Author(s):  
Robert A. Toro ◽  
Analio Dugarte-Dugarte ◽  
Jacco van de Streek ◽  
José Antonio Henao ◽  
José Miguel Delgado ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Surface Analysis ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Electrostatic Interactions ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Π Interactions

The structure of racemic (RS)-trichlormethiazide [systematic name: (RS)-6-chloro-3-(dichloromethyl)-1,1-dioxo-3,4-dihydro-2H-1λ6,2,4-benzothiadiazine-7-sulfonamide], C8H8Cl3N3O4S2 (RS-TCMZ), a diuretic drug used in the treatment of oedema and hypertension, was determined from laboratory X-ray powder diffraction data using DASH [David et al. (2006). J. Appl. Cryst. 39, 910–915.], refined by the Rietveld method with TOPAS-Academic [Coelho (2018). J. Appl. Cryst. 51, 210–218], and optimized using DFT-D calculations. The extended structure consists of head-to-tail dimers connected by π–π interactions which, in turn, are connected by C—Cl...π interactions. They form chains propagating along [101], further connected by N—H...O hydrogen bonds to produce layers parallel to the ac plane that stack along the b-axis direction, connected by additional N—H...O hydrogen bonds. The Hirshfeld surface analysis indicates a major contribution of H...O and H...Cl interactions (32.2 and 21.7%, respectively). Energy framework calculations confirm the major contribution of electrostatic interactions (E elec) to the total energy (E tot). A comparison with the structure of S-TCMZ is also presented.

scholarly journals Synthesis and Characterization of [2-CH3CH2C6H4NH3]6P6O18⋅4H2O

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Houda Marouani ◽  
Salem Slayyem Al-Deyab ◽  
Mohamed Rzaigui
Keyword(s):  
Hydrogen Bonds ◽  
Electrostatic Interactions ◽  
Three Dimensional ◽  
Spectroscopic Studies ◽  
Monoclinic System ◽  
Dimensional Network ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Ir Spectroscopic

Single crystals of [2-CH3CH2C6H4NH3]6P6O18⋅4H2O are synthesized in aqueous solution by the interaction of cyclohexaphosphoric acid and 2-ethylaniline. This compound crystallizes in the monoclinic system with P21/c space group the unit cell dimensions are: a=16.220(4) Å, b=10.220(5) Å, c=20.328(4) Å, β=113.24(3)∘, Z=2, and V=3096.5(18) Å3. The atomic arrangement can be described by layers formed by cyclohexaphosphate anions P6O186− and water molecules connected by hydrogen bonds O–H⋯O. These inorganic layers are developed around bc planes at x=1/2 and are interconnected by the H-bonds created by ammonium groups of organic cations. All the hydrogen bonds, the van der Waals contacts and electrostatic interactions between the different entities give rise to a three-dimensional network in the structure and add stability to this compound. The thermal behaviour and the IR spectroscopic studies of this new cyclohexaphosphate are discussed.

scholarly journals Crystal Structure of a Cationic Bile Salt Derivative ([3,5,7,12]-3-(2-naphthyloylamino)-7,12-dihydroxycholan-24-triethylammonium iodide)

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 135
Author(s):  
Francisco Meijide ◽  
María Pilar Vázquez-Tato ◽  
Julio Seijas ◽  
Santiago de Frutos ◽  
Juan V. Trillo Novo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Quaternary Ammonium ◽  
Electrostatic Interactions ◽  
Amide Bond ◽  
Orthorhombic Space Group ◽  
Steroid Nucleus ◽  
Quaternary Ammonium Group ◽  
Group A ◽  
Hydroxy Groups

The crystal structure of the iodide salt of a quaternary ammonium derivative of cholic acid having a naphthalene group attached to the 3rd position of the steroid nucleus through an amide bond ([3,5,7,12]-3-(2-naphthyloylamino)-7,12-dihydroxycholan-24-triethylammonium iodide) has been resolved. The compound crystallizes in the P212121 orthorhombic space group (a/Å = 10.9458(3); b/Å = 12.1625(3); c/Å = 28.4706(7)). The lateral chain adopts a fully extended tttt conformation because the quaternary ammonium group cannot participate in the formation of hydrogen bonds. The iodide ion is involved in the formation of hydrogen bonds as well as the amide group and the two steroid hydroxy groups. Hirshfeld surface analysis confirms that these contacts, as well as the electrostatic interactions, stabilize the structure. The helixes around the 21 screw axis are right-handed ones.

scholarly journals Intra- and Interpolyelectrolyte Complexes of Polyampholytes

2018 ◽  
Author(s):  
Sarkyt Kudaibergenov ◽  
Nurxat Nuraje
Keyword(s):  
Complex Formation ◽  
Hydrogen Bonds ◽  
Electrostatic Interactions ◽  
Water Soluble ◽  
Polymer Complex ◽  
Dye Molecules ◽  
Interpolymer Complexes ◽  
Interpolyelectrolyte Complexes ◽  
Points Of View

At present, a large amount of research works from experimental and theoretical points of view have been done on interpolyelectrolyte complexes formed by electrostatic interactions and/or interpolymer complexes stabilized by hydrogen bonds. On the contrary, relatively less attention has been given to polymer-polymer complex formation with synthetic polyampholytes. In this review the complexation of polyampholytes with polyelectrolytes is considered from theoretical and application points of view. Formation of intra- and interpolyelectrolyte complexes of random, regular, block, dendritic polyampholytes are outlined. The separate subchapter is devoted to amphoteric behavior of interpolyelectrolyte complexes. The realization of so-called “isoelectric effect” for interpolyelectrolyte complexes of water-soluble polyampholytes, amphoteric hydrogels and cryogels with respect to surfactants, dye molecules, polyelectrolytes and proteins is demonstrated.

scholarly journals E484K mutation in SARS-CoV-2 RBD enhances binding affinity with hACE2 but reduces interactions with neutralizing antibodies and nanobodies: Binding free energy calculation studies

2021 ◽  
Author(s):  
Wei Bu Wang ◽  
Yu Liang ◽  
Yu Qin Jin ◽  
Jing Zhang ◽  
Ji Guo Su ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Electrostatic Interactions ◽  
Tight Binding ◽  
Energy Calculation ◽  
Binding Affinities ◽  
Loop Region ◽  
Binding Interface

AbstractThe pandemic of the COVID-19 disease caused by SARS-CoV-2 has led to more than 100 million infections and over 2 million deaths worldwide. The progress in the developments of effective vaccines and neutralizing antibody therapeutics brings hopes to eliminate the threat of COVID-19. However, SARS-CoV-2 continues to mutate, and several new variants have been emerged. Among the various naturally-occurring mutations, the E484K mutation shared by both the 501Y.V2 and 501Y.V3 variants attracted serious concerns, which may potentially enhance the receptor binding affinity and reduce the immune response. In the present study, the molecular mechanism behind the impacts of E484K mutation on the binding affinity of the receptor-binding domain (RBD) with the receptor human angiotensin-converting enzyme 2 (hACE2) was investigated by using the molecular dynamics (MD) simulations combined with the molecular mechanics-generalized Born surface area (MMGBSA) method. Our results indicate that the E484K mutation results in more favorable electrostatic interactions compensating the burial of the charged and polar groups upon the binding of RBD with hACE2, which significantly improves the RBD-hACE2 binding affinity. Besides that, the E484K mutation also causes the conformational rearrangements of the loop region containing the mutant residue, which leads to more tight binding interface of RBD with hACE2 and formation of some new hydrogen bonds. The more tight binding interface and the new hydrogen bonds formation also contribute to the improved binding affinity of RBD to the receptor hACE2. In addition, six neutralizing antibodies and nanobodies complexed with RBD were selected to explore the effects of E484K mutation on the recognition of these antibodies to RBD. The simulation results show that the E484K mutation significantly reduces the binding affinities to RBD for most of the studied neutralizing antibodies, and the decrease in the binding affinities is mainly owing to the unfavorable electrostatic interactions caused by the mutation. Our studies revealed that the E484K mutation may improve the binding affinity between RBD and the receptor hACE2, implying more transmissibility of the E484K-containing variants, and weaken the binding affinities between RBD and the studied neutralizing antibodies, indicating reduced effectiveness of these antibodies. Our results provide valuable information for the effective vaccine development and antibody drugs design.

scholarly journals Solvation of apolar compounds in protic ionic liquids: the non-synergistic effect of electrostatic interactions and hydrogen bonds

2017 ◽  
Vol 19 (37) ◽  
pp. 25352-25359 ◽  
Author(s):  
I. A. Sedov ◽  
T. I. Magsumov ◽  
T. M. Salikov ◽  
B. N. Solomonov
Keyword(s):  
Ionic Liquids ◽  
Hydrogen Bonds ◽  
Synergistic Effect ◽  
Electrostatic Interactions ◽  
Protic Ionic Liquids ◽  
Better Than

Protic ionic liquids can dissolve apolar compounds better than aprotic ionic liquids.

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