Defining the hydrogen bond: An account (original) (raw)
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Defining the hydrogen bond: An account (IUPAC Technical Report)
Pure and Applied Chemistry, 2000
The term “hydrogen bond” has been used in the literature for nearly a century now. While its importance has been realized by physicists, chemists, biologists, and material scientists, there has been a continual debate about what this term means. This debate has intensified following some important experimental results, especially in the last decade, which questioned the basis of the traditional view on hydrogen bonding. Most important among them are the direct experimental evidence for a partial covalent nature and the observation of a blue-shift in stretching frequency following X
The Nature of Hydrogen Bond : New Iinsights Into Old Theories
2008
Almost hundred years old concepts on hydrogen bonding are brought into light to be compared to the contemporary views and theories. The first findings were based on qualitative grounds and relied upon observations of simple experiments and very much on human imagination. It is a challenge to contrast the old and new views and to see if they could be verified or revised. Over the last decades there has been tremendous development of methods for structure elucidation and many hydrogen bonded molecular structures were determined and deposited in structural data bases. The structural aspect of hydrogen bond in the solid state is well defined. However, the knowledge of hydrogen bonded structures in the liquid state is still limited. Studies on hydrogen bond dynamics, which are in progress, with new experimental methods will help to better understand processes in solutions. In many systems the functioning of hydrogen bonding at atomic level has been still an enigma. In biological reaction...
Physical Nature of Hydrogen Bond
Ukrainian Journal of Physics, 2015
The physical nature and the correct definition of hydrogen bond (H-bond) are considered. The influence of H-bonds on the thermodynamic, kinetic, and spectroscopic properties of water is analyzed. The conventional model of H-bonds as sharply directed and saturated bridges between water molecules is incompatible with the behavior of the specific volume, evaporation heat, and self-diffusion and kinematic shear viscosity coefficients of water. On the other hand, it is shown that the variation of the dipole moment of a water molecule and the frequency shift of valence vibrations of a hydroxyl group can be totally explained in the framework of the electrostatic model of H-bond. At the same time, the temperature dependences of the heat capacity of water in the liquid and vapor states clearly testify to the existence of weak H-bonds. The analysis of a water dimer shows that the contribution of weak H-bonds to its ground state energy is approximately 4-5 times lower in comparison with the energy of electrostatic interaction between water molecules. A conclusion is made that H-bonds have the same nature in all other cases where they occur. K e y w o r d s: hydrogen valence vibrations of a water molecule, frequency shift, hydrogen bond, electrostatic origin. The hydrogen bond is a phlogiston of the 20-th century.
2022
Hydrogen bonding has proved to be signi cantly important in all elds of physical sciences, and particularly in biology as was predicted by Nobel Laureate Linus Pauling. The nature and characteristics of hydrogen bond are, however, still being debated after almost a century of its rst recognition. The paper here, provides unequivocal differentiation between covalent character and electrostatic character of the hydrogen bond, on the basis of the 15 N-H spin-spin coupling in covalent bonding, and absence of any such spin-spin coupling across in the electrostatic bonding in 15 N labelled compounds. Hydrogen is, therefore, de nitely covalently bonded to its residence site. This NMR study also provides a direction towards gadolinium(III)-free contrast materials for MRI (Magnetic Resonance Imaging) diagnosis, due to concerns of safety. Moreover, the paper describes reactivity and selectivity in chemical reactions, aided and abated by intramolecular hydrogen bondings, and the characterization of cis-THI and Trans-THI, a novel synthetic chromophore related to naturally occurring trichosiderins, contained in human and animal keratinic materials. Trichosiderins, derived biochemically from sulphur containing amino acids, are now nding increased interest in medicinal research due to melanoma studies.
Hydrogen–Hydrogen Bonding: A Stabilizing Interaction in Molecules and Crystals
Chemistry: A European Journal, 2003
Bond paths linking two bonded hydrogen atoms that bear identical or similar charges are found between the ortho-hydrogen atoms in planar biphenyl, between the hydrogen atoms bonded to the C1 ± C4 carbon atoms in phenanthrene and other angular polybenzenoids, and between the methyl hydrogen atoms in the cyclobutadiene, tetrahedrane and indacene molecules corseted with tertiary-tetra-butyl groups. It is shown that each such H ± H interaction, rather than denoting the presence of ™nonbonded steric repulsions∫, makes a stabilizing contribution of up to 10 kcal mol À1 to the energy of the molecule in which it occurs. The quantum Keywords: bond path ¥ density functional calculations ¥ hydrogen bonds ¥ hydrogen ± hydrogen interaction [a] Prof. R.
A comprehensive analysis of hydrogen bond interactions based on local vibrational modes
International Journal of Quantum Chemistry, 2012
Local stretching modes for 69 different DH single bonds and 58 H• • • A H-bonds are calculated at the ωB97X-D/aug-cc-pVTZ level of theory to describe the changes in donor D and acceptor A upon forming the hydrogen-bonded complex. The intrinsic strength of the DH and AH interactions is determined utilizing the properties of a well-defined set of local, uncoupled vibrational modes. The local mode stretching force constant k a (HA) provides a unique measure of bond strength for both covalently and electrostatically bonded complexes. Generally applicable bond orders are derived, which can be related to the binding energies of the hydrogen bonded complexes. Although the red shifts in the DH stretching frequencies can be used to detect hydrogen bonding, they are not sufficient to assess the strength of hydrogen bonding. It is demonstrated that the calculated BSSE-corrected binding energies of hydrogen bonded complexes are related to the sum of bond order changes caused by hydrogen bonding.The covalent character of charge assisted hydrogen bonds is explained. Because local mode frequencies can also be derived from experimental normal mode frequencies, a new dimension in the study of hydrogen bonding is gained.
One Hundred Years After the Latimer and Rodebush Paper, Hydrogen Bonding Remains an Elephant!
Journal of the Indian Institute of Science, 2019
In the year 1920, Wendell M. Latimer and Worth H. Rodebush published a paper 1 in the Journal of the American Chemical Society titled "Polarity and Ionization from the Standpoint of the Lewis Theory of Valence". Reading this title today, it would not be obvious that this paper was credited by Linus Pauling in his classic book 2 as the first to mention hydrogen bond. Latimer and Rodebush start by discussing some previous work by Abegg and Bodlander 3 on strong and weak electrolytes, in which they introduced a property called 'electro-affinity' for elements! They point out that this property was commonly designated as electronegative and electropositive character of an element and it was related to its position in the periodic table! However, their paper focuses on Lewis's theory of 'two dots' (an electron pair) between two atoms as a bond, 4 extended and renamed as covalent bond by Langmuir. 5 Interestingly, the title of the paper by Lewis was "The Atom and the Molecules" and that of Langmuir was "The Arrangement of Electrons in Atoms and Molecules". Latimer and Rodebush explored 'associated liquids' and they had to worry about how the molecules arrange themselves together in
Nature of Hydrogen Bond in Water
Ukrainian Journal of Physics, 2012
The work is devoted to the investigation of the physical nature of H-bonds. The H-bond potential ΦH (r, Ω ) is studied as an irreducible part of the interaction energy of water molecules. It is defined as a difference between the generalized Stillinger–David potential and the sum of dispersive and multipole interactionpotentials. The relative contribution of ΦH (r, Ω ) to the intermolecular potential does not exceed (10–15)%.
H-Bond: Τhe Chemistry-BiologyH-Bridge
ChemistrySelect, 2016
This article is dedicated to the memory of Paul Cordopatis, beloved friend and colleague, with gratitude. H-bonding, as a non covalent stabilizing interaction of diverse nature, has a central role in the structure, function and dynamics of chemical and biological processes, pivotal to molecular recognition and eventually to drug design. Types of conventional and non conventional (HÀH, dihydrogen, H-p, CH-p, anti-, proton coordination and HÀS) H-bonding interactions are discussed as well as features emerging from their interplay, such as cooperativity (s-and p-) effects and allostery. Its utility in many applications is described. Catalysis, proton and electron transfer processes in various materials or supramolecular architectures of preorganized hosts for guest binding, are front-line technology. The H-bond-related concept of proton transfer (PT) addresses energy issues or deciphering the mechanism of many natural and synthetic processes. PT is also of paramount importance in the functions of cells and is assisted by large complex proteins embedded in membranes. Both intermolecular and intramolecular PT in H-bonded systems has received attention, theoretically and experimentally, using prototype molecules. It is found in rearrangement reactions, protein functions, and enzyme reactions or across proton channels and pumps. Investigations on the competition between intra-and intermolecular H bonding are discussed. Of particular interest is the H-bond furcation, a common phenomenon in protein-ligand binding. Multiple H-bonding (H-bond furcation) is observed in supramolecular structures.