Hydrogen bonding—definition

Brovchenko I, Oleinikova A. Four phases of amorphous water simulations versus experiment. 1. Chem. Phys. 2006 124 164505. Kumar R, Schmidt IR, Skinner IL. Hydrogen bonding definitions and dynamics in liquid water. 1. Chem. Phys. 2007 126 204107. Geiger A, StiUinger FH, Rahman A. Aspects of the percolation process for hydrogen-bond networks in water. 1. Chem. Phys. 1979 70 4185-4193. 

Keywords Hydrogen bonding definition of hydrogen bond classification of hydrogen bonding... 

Kumar R, Schmidt JR, Skinner JL (2007) hydrogen bond definitions and dynamics in hquid water. J Chem Phys 126 204107-1-204107-12... 

Much of our current knowledge of intermolecular interactions has been derived from the study of crystal structures. For example, it was not until an extensive survey of 1509 N—H---0=C hydrogen bonds in CSD structures that the O lone pair directionality of this key interaction was first recognized [31]. Another example is the detailed study of hydrogen bond geometries in 15 globular proteins carried out by Baker and Hubbard [32] and these hydrogen bond definitions, derived nearly 30 years... 

H-Bonds. Hydrogen bonding analyses of the protein and ligand complexes use a geometric hydrogen bond definition adopted in terms of the proton donor and lone pair acceptor positions. This information is useful to estimate the number of favorable hydrogen bonds for each inhibitor. 

In full accord with the hydrogen-bond definition [18], dihydrogen bonds feature short contacts H - -H + (less than the sum of the van der Waals radii, 2.4 A) and close to the linear -H +-X arrangement of atoms [13, 19]. As a result of the interacting bonds, both M-H and H-X are slightly elongated (by 0.003-0.030 A). The deviations of proton from... 

R. Kumar, J. R. Schmidt, and J. L. Skinner,/. Chem. Phys., 126,204107 (2007). Hydrogen Bonding Definitions and Dynamics in Liquid Water. 

In order to include other interactions such as dipolar or hydrogen bonding, many semiempirical approaches have been tried [196, 197, 200], including adding terms to Eq. X-45 [198, 201] or modifying the definition of [202, 199]. Perhaps the most well-known of these approaches comes from Fowkes [203, 204] suggestion that the interactions across a water-hydrocarbon interface are dominated by dispersion forces such that Eq. X-45 could be modified as... 

FIG. 13 Average number of hydrogen bonds (for definition see text) as a function of p in five simulations at different levels of hydration in a Vycor pore. Full hues show the number of water-water bonds, long-dashed hnes show the number of bonds between water molecules and Vycor, and short-dashed lines denote the sum of the two. From top to bottom, the frames correspond to a water content of about 96, 74, 55, 37, and 19% of the maximum possible (corresponding to 2600, 2000,1500, 1000, and 500 water molecules in a cylindrical cavity of about 4nm diameter and 7.13 nm length). (From Ref. 24.)... 

The three-dimensional conformation of a protein is called its tertiary structure. An a-helix can be either twisted, folded, or folded and twisted into a definite geometric pattern. These structures are stabilized by dispersion forces, hydrogen bonding, and other intermo-lecular forces. 

Human embryonic kidney cells, 21 Human genome, 2 Hydrogen bonding, 10 Hypothesis testing definition of, 239 description of, 227, 233 dose-response curves for, 239-243 F-test, 242t... 

It has been pointed out321-324 that the two groups of solvents differ by some definite structural features. In particular, ED, 1,2-BD, and 1,3-BD possess vicinal OH groups that can form intramolecular hydrogen bonds. For these solvents, the ability of the organic molecule to interact with neighboring molecules is reduced. This results in the possibility of a different orientation at the interface because of different interactions of the OH groups with the Hg surface.323 The different molecular structure leads to different dipolar cooperative effects. As a result, the dependence of C on the bulk permittivity follows two different linear dependencies. 

An alcohol, by definition, will contain an OH group in its structure. Therefore, we expect hydrogen bonding to occur ... 

Partitioning or cell-based methods provide an absolute measure of the chemical space covered by a collection of compounds. They are based on the definition of a low-dimensional chemistry space, for example, one based on a small number of physicochemical properties such as molecular weight, calculated logP, and number of hydrogen bond donors [45]. Each property defines an axis of the chemistry-space. The range of values for each property is divided into a set of bins, and the combinatorial product of all bins then defines the set of cells or partitions that make up the space. 

Although Lewis and Bronsted bases comprise the same species, the same is not true of their acids. Lewis acids include bare metal cations, while Bronsted-Lowry acids do not. Also, Bell (1973) and Day Selbin (1969) have pointed out that Bronsted or protonic acids fit awkwardly into the Lewis definition. Protonic acids cannot accept an electron pair as is required in the Lewis definition, and a typical Lewis protonic add appears to be an adduct between a base and the add (Luder, 1940 Kolthoff, 1944). Thus, a protonic acid can only be regarded as a Lewis add in the sense that its reaction with a base involves the transient formation of an unstable hydrogen bond adduct. For this reason, advocates of the Lewis theory have sometimes termed protonic adds secondary acids (Bell, 1973). This is an unfortunate term for the traditional adds. 

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