Chemistry of Non-Covalent Interactions

Non-covalent interactions govern phenomena related to condensation, solvation, adsorption, and crystallization. A role of non-covalent interactions in biology spans from controlling of protein folding and functions of nucleic acids to drug design, molecular recognition, and enzyme catalysis. 

EFPl and general EFP methods were extensively used to investigate non-covalent interactions in clusters and liquids. For example, EFPl water potential was used to characterize structures and binding energies in water clusters and liquid water [31-33]. General EFP method was employed in studies of alcohol-water clusters and mixtures [34-35] and solvation of ions [36-37], benzene and substituted benzene dimers [14, 38], water-benzene complexes [39], intermolecular interactions in st3mene clusters [40] and DNA base pairs [5,41]. 

Detailed and balanced description of different parts of intermolecular interactions is unique feature of the EFP method, which enables predictive investigations of heterogeneous systems. One vivid example of structural heterogeneity is observed in water-benzene complexes due to interplay among H-bonding, tz-tz bonding, and tt-H bonding. 

EFP interaction energies in the water dimer, benzene dimers, and water-benzene dimers are compared in Fig. 5.1 [39]. Interaction in the water dimer is dominated by the Coulomb term (—8.6 Real/ mol), whereas the polarization and dispersion components are almost 10 times weaker. Contrarily, dispersion forces (—4.9 Real/ mol) determine binding in the parallel-displaced benzene dimer. Interestingly, the two structures of the benzene-water dimer and the T-shaped benzene dimer exhibit significant contributions from 

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For the purposes of this review the criterion has been refined to include only those porphyrin complexes where there is direct structural or spectroscopic evidence for a metal-carbon interaction. This interaction will not, however, be limited to covalent bonds. The last decade has seen the rise in importance of supramolecular chemistry and non-covalent interactions, and a small set of examples involving porphyrin complexes will be included as the last section in the review. 

Noncovalent interactions play a special role in synthetic procedures used to assemble various types of supramolecular species. These syntheses rely on the stabilization provided by non-covalent interactions between recognition sites incorporated within precursors. Various types of non-covalent interactions can be used as a recognition motif utilized to guide the synthesis.Targeted synthesis of macro- and supramolecular structures of various sizes, shapes, and functionality has now become possible. Supramolecular chemistry offers incredible applications in various fields such as medicinal chemistry (drug delivery systems),host-guest chemistry,catalysis,and molecular electronics. ... 

C.A. Schalley, Supramolecular chemistry goes gas phase The mass spectrometric examination of non-covalent interactions in host-guest chemistry and molecular recognition. Int. J. Mass Spectrom. 11, 11-39 (2000)... 

Abstract The preparation of chiral functional materials with new, improved, and interesting properties is aided tremendously by control of the spatial arrangement of the functional units within them. The use of non-covalent interactions is absolutely critical in this regard, and the molecular-supramolecular balance has to be strictly controlled. The conducting, magnetic and optical properties of chiral materials whose function is profoundly influenced by supramolecular chemistry will be reviewed. Special emphasis is placed on the control of helical arrangements in liquid crystalline systems, in which both chiral induction and spontaneous resolution are important phenomena which can be controlled. 

One of the key goals in nanochemistry is the creation of devices that can function on the nanometre scale. The benefits that accrue with such miniaturisation include increased component density, lower costs and faster speeds, with longterm goals in molecular computing. A device can be described as an object that is invented and has a purpose. However, what is a device on the supramolecular level Thus far, we have considered the definition of supramolecular chemistry in terms of non-covalent interactions. However, we can consider a supramolecular device to be a system made up of linked molecular components with identifiable properties that are intrinsic to each component. The interaction energy between... 

The functional diversity of flavoproteins results from the broad range of redox potentials that are accessible to the flavin cofactors, as well as their ability to switch between one or two electron redox chemistry. In solution, flavins are found in equilibrium between the oxidized, reduced and the semi-quinone radical forms, and have a redox potential of about —210 mV (versus the normal hydrogen electrode) at neutral pH. However, in the protein-bound form, the redox equilibrium can be shifted and the redox potential may span up to 600 mV (Massey 2000). This arises from the fact that flavin-protein interactions may engage a number of non-covalent interactions such as 7i-stacking, hydrophobic effects, hydrogen bonding and electrostatic interactions, which will ultimately determine the flavin redox potential. 

Chemistry beyond the molecule , bearing on the organized entities of higher complexity that result from the association of two or more chemical species held together by intermolecular forces. Its development requires the use of all resources of molecular chemistry combined with the designed manipulation of non-covalent interactions so as to form supramolecular entities, supramolecules possessing features as well defined as those of molecules themselves. ... 

Non-covalent bonding is the dominant type of inter-molecular force in supramolecular chemistry. These non-covalent interactions include ionic bond, hydrophobic interactions, hydrogen bonds, Van der Waals forces and dipole-dipole bonds. 

Quantum Monte Carlo (QMC) effectively solves the many-body problem by a random walk through the electronic configuration space it has been shown to be a promising method in quantum chemistry. One of the major advantages of QMC is the ability to perform massively parallel calculations, which can effectively increase the scope of what is computational tractable by distributing the work over hundreds or even thousands of processors. QMC is a general method and, therefore, also has been applied recently to the computation of non-covalent interactions (e.g., the S22 data set) (Korth et al. 2008). 

Hydrogen bonds are ubiquitous in nature. As arguably the most important type of non-covalent interactions, hydrogen bonds are crucial for various processes of life and also allow for the specific binding of substrates in enzyme pockets [1]. Consequently, generations of researchers have mimicked nature to develop applications of hydrogen bonds in chemistry with ever-increasing complexity and control [2, 3]. 

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