Properties of hydrogen bonds

Two hydrogen-bonded electronegative atoms can approach each other more closely than the sum of their molecular radii. In other words, the intermolecular distance between B. .. H is less than the value expected from summing the two van der Waals radii of 

In Section 2.1.4 we described the vibrational properties and potential wells of covalent bonds. Any bond possesses thermal motion, even at absolute zero, due to the zero point vibrational state. For a Dn-H bond, formation of a hydrogen bond to Ac restricts the motion of the hydrogen atom because the hydrogen is now restrained by two bonds rather than one. Using infrared spectroscopy to measure the vibrational frequencies of the Dn-H bond is therefore a good experimental tool for characterizing hydrogen bonds. The vibrational frequences of both the Dn-H bond and the H Ac bond can often be observed. 

Potential energy plots for the vibrational states of various hydrogen bonds. 

A normal hydrogen bond, B. a low-barrier hydrogen bond, and C. a no-barrier hydrogen bond. 

Characteristics Vibrational Modes for Normal Hydrogen Bonds, R-Dn-H Ac  

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Barone, V., Adamo, C., 1997b, Toward a General Protocol for the Study of Static and Dynamic Properties of Hydrogen-Bonded Systems , Int. J. Quant. Chem., 61, 429. 

Del Bene, J. E., Person, W. B., Szczepaniak, K., 1995, Properties of Hydrogen-Bonded Complexes Obtained from the B3LYP Functional With 6-31G(d,p) and 6-31+G(d,p) Basis Sets Comparison With MP2/6-31+G(d,p) Results and Experimental Data , 7. Phys. Chem., 99, 10705. 

Scheiner, S., 1991, Calculating the Properties of Hydrogen Bonds by Ab Initio Methods , Rev. Comput. Chem., 2, 165. 

We focus our review on the dynamical properties of hydrogen bonds X-H Y which have been widely studied by means of infrared spectroscopy. Indeed, the infrared (IR) spectra of hydrogen bonds (H bonds) appeared to be a very useful tool because the broad stretching band vs (X-H - Y) is very informative, containing complete information on the electronic and consequently nuclear... 

It is the sensitivity of hydrogen bonds to their external environment that provide the pH-dependence of physical properties of hydrogen-bonding interpolymer complexes that are of interest to us. 

The manner in which four characteristic properties of hydrogen bonds vary are shown diagrammatically in Fig. 4(a-d). In every case the lower limit of the hydrogen-bond length, -"B the very strong hydrogen... 

S. Scheiner Calculating the Properties of Hydrogen Bonds by ab initio Methods , in K.B. Lipkowitz and D.B. Boyd (Eds.), Reviews in Computational Chemistry II, VCH Publisher, New York, 165 (1991) ... 

In order to understand these extreme changes in physical and chemical properties of hydrogen-bonded systems, first attempts to model their dynamics were related to rather simple structures, as exhibited by the KDP family or squaric acid and its analogues. The isotope effects on their ferro- or anti-ferroelectric transition temperatures are listed in Table 1 together with the corresponding isotope exponent. 

E. R. Lippincott The proposed model is certainly empirical. However, the internuclear potential function used for the terms V1 and F2 may be derived from a quantum mechanical model which lends support to their use in such a treat-ment of hydrogen bond systems. Professor Pauling is quite right in suggesting that the terms Vx and F2 may include some electrostatic contribution, since it is known that the internuclear potential function used correlates properties fairly well for partial polar bonds. Nevertheless the fact that additional terms of the electrostatic type are not needed to describe a number of the important properties of hydrogen bond systems, suggests that the covalent, repulsion and dispersions energy contributions are more important than the electrostatic contribution. 

A detailed, advanced discussion of the structure and properties of hydrogen bonds, including those in water and biomolecules. 

Scheiner S. Calculating the properties of hydrogen bonds by ab initio methods. In Lipkowitz KB, Boyd DB, eds. Reviews in Computational Chemistry. Vol. 2. New York VCH, 1991 165-218. 

Table 1.5 Properties of hydrogen bonded interactions (A-H = hydrogen bond acid, B = hydrogen bond base).

Steve Scheiner, Calculating the Properties of Hydrogen Bonds by Ab Initio Methods. 

Legon, A.C. and Millen D.J. (1986). Gas-phase spectroscopy and the properties of hydrogen-bonded dimers HCN---HF as the spectroscopic prototype, Chem. Rev. 86, 635-657. 

The validity of the two approaches sketched above has been quite amply tested against the ability of reproducing various molecular properties of hydrogen-bonded systems (see elsewhere in this book) including vibrational spectroscopies [11,54-56], For example, in Figure 2.11 calculated versus experimental IR spectra of gallic acid in water solution are reported for different levels of treatment of the specific solute-solvent interaction [54],... 

L.F. Pacios, Change with the intermolecular distance of electron properties of hydrogen bond dimers at equilibrium and non-equilibrium geometries. Struct. Chem. 16, 223-241 (2005)... 

J. E. Del Bene, Anharmonicities, isotopes, and IR and NMR properties of hydrogen-bonded complexes, in Isotope Effects in Chemistry and Biology, A. Kohen and H.-H. Limbach, eds., CRC Press Taylor and Francis Group, Boca Raton, 2006, p. 153. 

Physical and Chemical Properties of Hydrogen-Bond Containing Complexes... 

ELECTRONIC PROPERTIES OF HYDROGEN BOND NETWORKS IMPLICATIONS FOR SOLVENT EFFECTS IN POLAR LIQUIDS... 

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