Noncovalent interactions analysis

Noncovalent interactions, both inter- and intramolecular, are of considerable importance in determining the physical properties of molecules. Such interactions can be classified as hydrogen-bonding or non-hydrogen-bonding. In this section we will explore some recent uses of the electrostatic potential in the analysis of both types. 

Murray, J. S., K. Paulsen, and P. Politzer. 1994. Molecular Surface Electrostatic Potentials on the Analysis of Non-Hydrogen-Bonding Noncovalent Interactions. Proc. Ind. Acad. Sci. (Chem. Sci.) 106, 267. 

Charges are heavily delocalized in organic ions, which complicate the theoretical analysis of ion pairing. Between neutral polar molecules the electrostatic contributions comes mostly from dipole-dipole interactions. Perhaps van der Waals interactions are the most important class of dipole-dipole interactions where one or both molecules do not have a permanent dipole. These interactions are valid for any two atoms that come into close contact with each other, and are called van der Waals interactions. Another very important noncovalent interaction is the hydro-phobic interaction. As the term hydrophobic suggests, this interaction is an effective interaction between two nonpolar molecules that tend to avoid water and, as a result, prefer to cluster around each other. 

Analysis of supramolecular structures in ionic liquids Supramolecular assemblies are the molecular base for some of the unique properties of ILs. Therefore, the knowledge of the nature, type, and strength of these structures [23] is a prerequisite for a deeper understanding of ILs as well as for the tailor-made design of new compounds. The most important noncovalent interactions responsible for the formation of such a structure are C-H hydrogen bonds [25]. Other interactions encompass the formation of clusters by ion pairing, which can be found, for example, in chloroaluminates [12]. 

J.S. Murray et al., Molecular surface electrostatic potentials in the analysis of non-hydrogen-bonding noncovalent interactions. Proc. Indian Acad. Sci. 106, 267-275 (1994)... 

J.S. Murray, P. Politzer, Statistical analysis of the molecular surface electrostatic potential An approach to describing noncovalent interactions in condensed phases. J. Mol. Struct. (Theo-chem) 425, 107-114 (1998)... 

Mehler, E.L., Self-consistent, nonorthogonal group function approximation for polyatomic systems. II. Analysis of noncovalent interactions. J.Chem.Phys. (1981) 74 6298-6306. 

To benefit general readers, the discussion has been limited to methodologies that are accessible to nonspecialists and that can be carried out on commercially available spectrometers without special modifications. The chapter illustrates the principles of mass spectrometry by demonstrating how various techniques [MALDI, ESI, Fourier transform ion cyclotron resonance (FT-ICR), ion traps, and tandem mass spectrometry (MS-MS)] work. It also provides examples of utilizing mass spectrometry to solve biological and biochemical problems in the field of protein analysis, protein folding, and noncovalent interactions of protein-DNA complexes. 

Murray, J.S. and Politzer, P. (1998). Statistical Analysis of the Molecular Surface Electrostatic Potential An Approach to Describing Noncovalent Interactions in Condensed Phases. J.Mol. Struct.(Theochem), 425,107-114. 

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