scholarly journals Controlling hydrogel properties by tuning non-covalent interactions in a charge complementary multicomponent system

2021 ◽  
Author(s):  
Santanu Panja ◽  
Annela Seddon ◽  
Dave Adams
Keyword(s):  
Small Molecule ◽  
Multicomponent System ◽  
System P ◽  
Non Covalent Interactions ◽  
The Individual ◽  
A Charge ◽  
Covalent Interactions

Mixing small molecule gelators is a promising route to prepare useful and exciting materials that cannot be accessed from any of the individual components. Here, we describe pH-triggered hydrogelation by...

scholarly journals Supramolecular interactions between catalytic species allow rational control over reaction kinetics

2019 ◽  
Vol 10 (39) ◽  
pp. 9115-9124 ◽  
Author(s):  
Abraham J. P. Teunissen ◽  
Tim F. E. Paffen ◽  
Ivo A. W. Filot ◽  
Menno D. Lanting ◽  
Roy J. C. van der Haas ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Reaction Kinetics ◽  
Phase Transfer ◽  
Supramolecular Interactions ◽  
Two Phase ◽  
Phase Transfer Catalysts ◽  
System P ◽  
Non Covalent Interactions ◽  
Rational Control ◽  
Covalent Interactions

The non-covalent interactions between two phase-transfer catalysts allow tuning of reaction kinetics from bimolecular, to pseudo 0th order, to sigmoidal. Kinetic models and DFT calculations are used to obtain detailed insight in the system.

Weak interactions and their impact on cellulose dissolution in an alkali/urea aqueous system

2017 ◽  
Vol 19 (27) ◽  
pp. 17909-17917 ◽  
Author(s):  
Sen Wang ◽  
Peng Sun ◽  
Maili Liu ◽  
Ang Lu ◽  
Lina Zhang
Keyword(s):  
Physical Chemistry ◽  
Weak Interactions ◽  
Aqueous System ◽  
Cellulose Dissolution ◽  
System P ◽  
Non Covalent Interactions ◽  
Covalent Interactions

This work exhibited the indispensability and significance of weak non-covalent interactions between urea and macromolecules in a sophisticated physical chemistry process.

scholarly journals Ability of B12N12 fullerènes like nano-cage for sensing and improving the antioxidant activity of juglone and its derivative: DFT investigation

2021 ◽  
Author(s):  
Vincent de Paul Zoua ◽  
Aymard Fouegue ◽  
Désiré Mama ◽  
Julius Ghogomu ◽  
Rahman Abdoul Ntieche
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Nbo Analysis ◽  
Hydrogen Atom Transfer ◽  
Carbonyl Groups ◽  
Functional Theory ◽  
Non Covalent Interactions ◽  
A Charge ◽  
Covalent Interactions ◽  
Theoretical Results

Density functional theory (DFT) calculations were adopted in this work to investigate the ability of the B12N12 fullerene like nano-cage for sensing juglone (Jug) and one of its derivative (Jug-OH) using DFT based methods in gas phase, pentyl ethanoate (PE) and water. Results showed that B12N12 is able to adsorbed Jug preferentially by binding to one of the O-atom of its carbonyl groups. Based on NBO analysis, a charge transfer from the oxygen atoms of Jug and Jug-OH to the anti-bonding orbital of B was revealed. QTAIM analysis showed that the B12N12-Jug and B12N12-Jug-OH complexes are stabilized by a partially covalent B-O bond in addition to attractive non covalent interactions. The ability of Jug, Jug-OH as well as their complexes A and A-OH to scavenge radicals has been investigated via the usual hydrogen atom transfer (HAT) mechanism in the three media of study previously stated. Theoretical results revealed that in PE and water, the complexes are better antioxidant than Jug and Jug-OH. These results provide fundamental knowledge for the development of new antioxidant delivery careers.

scholarly journals Conformational trimorphism of bis(2,6-dimesitylphenyl)ditelluride

2018 ◽  
Vol 233 (9-10) ◽  
pp. 707-721 ◽  
Author(s):  
Simon Grabowsky ◽  
Ole Mallow ◽  
Rumpa Pal ◽  
Yves Pergandé ◽  
Enno Lork ◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Torsion Angles ◽  
Thermoanalytical Investigations ◽  
Crystallization Experiments ◽  
Polymorphic Modifications ◽  
Non Covalent Interactions ◽  
London Dispersion ◽  
The Individual ◽  
Covalent Interactions ◽  
Intramolecular Forces

Abstract Besides the previously known α-form (monoclinic, P21/c, Z=4) of bis(2,6-dimesitylphenyl)ditelluride, two new polymorphic modifications, namely the β-form (monoclinic, P21/c, Z=8) and the γ-form (triclinic, P1̅, Z=2), were obtained serendipitously during chemical reactions. In all three modifications, the individual molecules possess significantly different conformations and bond parameters, such as Te–Te bond lengths, C–Te–Te bond angles, C–Te–Te–C torsion angles and intramolecular Menshutkin interactions, which is also reflected in their non-covalent interactions with adjacent molecules in the crystal lattice via London dispersion and electrostatic forces. The interplay between intermolecular and intramolecular forces in these conformational polymorphs was investigated using quantum chemical calculations, which reveal that the β-form should be thermodynamically stable at absolute zero. In contrast, crystallization experiments and thermoanalytical investigations indicate that the α-form is stable at high temperatures and therefore, both forms might be related by enantiotropism.

Non-covalent interactions in the multicomponent crystal of 1-aminocyclopentane carboxylic acid, oxalic acid and water: a crystallographic and a theoretical approach

2017 ◽  
Vol 73 (5) ◽  
pp. 968-980 ◽  
Author(s):  
Asiloé J. Mora ◽  
Lusbely M. Belandria ◽  
Gerzon E. Delgado ◽  
Luis E. Seijas ◽  
Angel Lunar ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Amino Acid ◽  
Critical Points ◽  
Three Dimensional ◽  
Dispersion Interactions ◽  
X Ray Diffraction ◽  
Carboxylate Groups ◽  
Non Covalent Interactions ◽  
A Charge ◽  
Covalent Interactions

Single-crystal X-ray diffraction and quantum mechanical theories were used to examine in detail the subtle nature of non-covalent interactions in the [2:1:1] multicomponent crystal of 1,1-aminocyclopentanecarboxylic acid:oxalic acid:water. The crystal, which is a hydrate salt of the amino acid with the hydrogen-oxalate ion, also contains the zwitterion of the amino acid in equal proportions. It was found that a dimeric cation [Acc5(Z)...Acc5(C)]+bonded by an O—H...O hydrogen bond exists due to a charge transfer between acid and carboxylate groups. The three-dimensional crystal is built by blocks stacked along the [101] direction by dispersion interactions, with each block growing along two directions: a hydrogen oxalate HOX−...HOX−catameric supramolecular structure along the [010] direction; and double ...HOX−—W—[Acc5(Z)... Acc5(C)]+... chains related by inversion centers along the [1 0 {\bar 1}] direction. A PBE-DFT optimization, under periodic boundary conditions, was carried out. The fully optimized structure obtained was used to extract the coordinates to calculate the stabilization energy between the dimers under the crystal field, employing the M062X/aug-cc-pVTZ level of theory. The non-covalent index isosurfaces employed here allow the visualization of where the hydrogen bond and dispersion interactions contribute within the crystal. The crystal atomic arrangements are analyzed by employing the Atoms in Molecules and electron localization function theories. Within this context, the presence of density bond critical points is employed as a criterion for proving the existence of the hydrogen bond and it was found that these results agree with those rendered by the crystallographic geometrical analysis, with only three exceptions, for which bond critical points were not found.

scholarly journals Hydrazone-Based Small-Molecule Chemosensors

2020 ◽  
Author(s):  
Thiago Moreira Pereira ◽  
Arthur Eugen Kümmerle
Keyword(s):  
Small Molecule ◽  
Functional Group ◽  
Structural Characteristics ◽  
Biological Interest ◽  
Non Covalent Interactions ◽  
Covalent Interactions

The hydrazone functional group is widely applied in several fields. The versatility and large use of this chemotype are attributed to its easy and straightforward synthesis and unique structural characteristics which is useful for different chemical and biological purposes. Recently hydrazone scaffold has been widely adopted in the design of small-molecule fluorescent and colorimetric chemosensors for detecting metals and anions because of its corresponding non-covalent interactions. This chapter provides an overview of hydrazone-based fluorescent and colorimetric chemosensors for anions and metals of biological interest, with their representative rational designs in the last 15 years. We hope this chapter inspires the development of novel and powerful fluorescent and colorimetric chemosensors for a broad range of applications.

NON COVALENT INTERACTIONS IN LARGE DIAMONDOID DIMERS IN THE GAS PHASE - A MICROWAVE STUDY

2017 ◽  
Author(s):  
Cristobal Perez ◽  
Melanie Schnell ◽  
Peter Schreiner ◽  
Norbert Mitzel ◽  
Yury Vishnevskiy ◽  
...  
Keyword(s):  
Gas Phase ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Vapour Pressure Isotope Effect on Evaporation from Pure Organic Phases - a PIMD Approach

2020 ◽  
Author(s):  
Luis Vasquez ◽  
Agnieszka Dybala-Defratyka
Keyword(s):  
Path Integral ◽  
Vapour Pressure ◽  
Density Functional ◽  
Isotope Effects ◽  
Tight Binding ◽  
Decomposition Analysis ◽  
Energy Decomposition Analysis ◽  
Special Importance ◽  
Non Covalent Interactions ◽  
Covalent Interactions

<p></p><p>Very often in order to understand physical and chemical processes taking place among several phases fractionation of naturally abundant isotopes is monitored. Its measurement can be accompanied by theoretical determination to provide a more insightful interpretation of observed phenomena. Predictions are challenging due to the complexity of the effects involved in fractionation such as solvent effects and non-covalent interactions governing the behavior of the system which results in the necessity of using large models of those systems. This is sometimes a bottleneck and limits the theoretical description to only a few methods.<br> In this work vapour pressure isotope effects on evaporation from various organic solvents (ethanol, bromobenzene, dibromomethane, and trichloromethane) in the pure phase are estimated by combining force field or self-consistent charge density-functional tight-binding (SCC-DFTB) atomistic simulations with path integral principle. Furthermore, the recently developed Suzuki-Chin path integral is tested. In general, isotope effects are predicted qualitatively for most of the cases, however, the distinction between position-specific isotope effects observed for ethanol was only reproduced by SCC-DFTB, which indicates the importance of using non-harmonic bond approximations.<br> Energy decomposition analysis performed using the symmetry-adapted perturbation theory (SAPT) revealed sometimes quite substantial differences in interaction energy depending on whether the studied system was treated classically or quantum mechanically. Those observed differences might be the source of different magnitudes of isotope effects predicted using these two different levels of theory which is of special importance for the systems governed by non-covalent interactions.</p><br><p></p>

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