Van der Waals forces hydrogen bonding

Absorption, metaboHsm, and biological activities of organic compounds are influenced by molecular interactions with asymmetric biomolecules. These interactions, which involve hydrophobic, electrostatic, inductive, dipole—dipole, hydrogen bonding, van der Waals forces, steric hindrance, and inclusion complex formation give rise to enantioselective differentiation (1,2). Within a series of similar stmctures, substantial differences in biological effects, molecular mechanism of action, distribution, or metaboHc events may be observed. Eor example, (R)-carvone [6485-40-1] (1) has the odor of spearrnint whereas (5)-carvone [2244-16-8] (2) has the odor of caraway (3,4). 

Electronic characteristics and their effects on the ability of side chains to engage in ionic bonding, covalent bonding, hydrogen bonding, van der Waals forces, and acid-base chemistry... 

Nonmodified silica gel is used most commonly for the separation of substances of medical interest. The separation is based on the interactions (hydrogen bonding, van der Waals forces, and ionic bonding) between the molecules of drugs, lipids, bile acids, etc., and the silica gel. Alumina has similar properties but is rarely used. Successful separation of endogenous substances, drugs, or their metabolites can also be achieved using physically or chemically modified silica gel. 

The directed manipulation of intermolecular interactions (hydrogen bonding, van der Waals forces, metal coordination) gives access to a supramolecular engineering of molecular assemblies and of polymers (see, for instance, [7.10-7.13, 7.44, 9.142, 9.157, 9.161-9.163]) through the design of instructed monomeric and polymeric species. It leads to the development of a supramolecular materials chemistry (see Section 9.8). 

Intermolecular attractions include dipolar attractions, as well as van der Waals forces and hydrogen bonding. van der Waals forces are similar to dipolar attractions but result from instantaneous dissymmetry of charge, which may disappear the next instant. The more electrons in the molecule, the greater is the van der Waals force. However, van der Waals forces tend to be lower in magnitude than dipolar attractions. 

Molecular associations between polymer segments occur through the cooperation of several intermolecular forces such as hydrogen bonding, van der Waals forces, and electrostatic attractive and repulsive forces. The disruption of junction zones is associated with a high activation energy, further indicating that many intermolecular forces cooperate to retain the structure of each junction.f ... 

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