Hydrogen bonding, 39 - Electrostatic interactions, 40 - Hydrophobicity, 44 - Dispersion forces

The interactions between molecules of polysaccharides and proteins, can be given by covalent bonds, known as conjugated, they form veiy stable structures. There also are physical forces, non-covalent interactions such as electrostatic, hydrophobic, steric, hydrogen bonding, and Van der Waals forces. These interactions are involved in the formation and stabilization of dispersions [80]. 

Fig. 7. Simple schematic diagram representing three conformational states of proteins The expanded denatured state whose structure is determined by steric interactions the compact denatured state, with structure determined by hydrophobic buril and the native state, with structure determined by dispersion forces, hydrogen bonds, and electrostatics.

Solvent-resistant elastomers, 9 560-562 Solvent-resistant membranes, 27 656 Solvent-resistant rubber, 22 583-584 Solvent selection, in liquid-liquid extraction, 70 746-749 Solvent-solute interactions, 26 855,23 91-96 acid/base interactions in, 23 96 dispersion in, 23 92-93 electrostatic forces in, 23 91-92 hydrogen bonding in, 23 94-95 hydrophobic interactions in, 23 95 polarization in, 23 92 repulsion in, 23 93-94 Solvent strength, of pure fluids, 24 3-4 Solvent systems, for acid gas removal, 72 376-377... 

Electrostatic interactions occur between the ionic head groups of the surfactant and the oppositely charged solid surface (head down adsorption with monolayer structure) [56]. Acid-base interactions occur due to hydrogen bonding or Lewis acid-Lewis base reactions between solid surface and surfactant molecules (head down with monolayer structure) [57]. Polarisation of jt electrons occurs between the surfactant head group which has electron-rich aromatic nuclei and the positively charged solid surface (head down with monolayer structure) [58]. Dispersion forces occur due to London-van der Waals forces between the surfactant molecules and the solid surface (hydrophobic tail lies flat on the hydrophobic solid surface while hydrophilic head orients towards polar liquid) [59]. 

Several artificial systems in which intermolecular and noncovalent bonds between two or more chemical entities have been formed have been reported. The driving forces which hold together these entities are mainly dealing with electrostatic interactions, metal coordination, hydrogen bond, n-n stacking as well as hydrophobic, van der Waals, and dispersion interactions. Therefore, such concept has paved the way for designing and building systems with specific and novel features, whose properties could be far beyond the simple sum of... 

The various properties of molecules that can be used in a QSAR are often designed to quantitate the tendency of the molecules to participate in one of the fundamental types of intermolecular interactions electrostatic, hydrogen bonding, dispersion forces, and hydrophobic interactions. In addition, the possibility of steric interference with an interaction is considered. Other methods capitalize on the fact that the 2D structure of a molecule indirectly encodes its properties, instead generate descriptors without an explicit relationship to some physical property. 

The noncovalent forces that bind the substrate to the active site are the same forces that account for the conformations of proteins dispersion forces, electrostatic forces, hydrogen bonding, and hydrophobic interactions. The amino acids located in the active site are arranged so that they can interact specifically with the substrate. 

Intermolecular interaction A collective term for the attractive (and repulsive) forces that control the association of two or more molecular entities. Intermolecular interactions include electrostatic (Coulombic) forces, van der Waals forces including dispersion (London) forces, hydrogen bonding interactions, Lewis acid—Lewis base interactions, electron-donor—electron-acceptor interactions, and the hydrophobic (solvophobic) effect. The same types of interactions can also occur between parts of the same molecular entity (intramolecular interactions). Although some interactions are weak relative to a covalent bond, others are not. The term includes a range of bonding characters from predominantly covalent, polar covalent, or ionic. 

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