Amide-amide hydrogen bonds have been implicated in directing protein folding and enhancing protein stability. Inversion transfer (13)C NMR spectroscopy and IR spectroscopy were used to compare the ability of various amide solvents and of water to alter the rate of the cis-trans isomerization of the prolyl peptide bond of Ac-Gly-[β,δ-(13)C]Pro-OMe and the amide I vibrational mode of [(13)C=O]Ac-...

a new metal-organic compound, [fe(pydc)(dmso)(h2o)cl], (where pydc is pyridine-2, 6-dicarboxylate and dmso is dimethyl sulfoxide), has been synthesized and characterized by singlecrystal x-ray diffraction, tga/dta, ir and raman spectroscopy. green-yellow crystals,crystallized in the monoclinic system, space group p21/n, a = 7.2461(4) å, b = 10.3018(4) å, c =17.7667(10) å, α = 90°, β = 90.014°(5...

the effect of interactions of various ia and iia cations with two positions of the adenine-thymine (a−t) and guanine-cytosine (g−c) base pairs on the geometries and individual hydrogen bond (hb) energies have been investigated by using the atoms in molecules (aim) method at the b3lyp/6-311++g(d,p) level of theory. the cations that possess higher charge/radius (q/rad) ratio make higher changes o...

The hydrogen bond (HB) is one of the fundamental noncovalent interactions between a drug molecule and its local environment. For drug molecules, this local environment may be a biological target, a biological off-target, aqueous solution, a lipid membrane, or even a crystalline solid. Consequently, hydrogen bonding impacts a wide range of molecular properties critical to drug design including p...

It is generally accepted that the distinctive properties of water can be ascribed to hydrogen bonding [1]. The fundamental dynamical process of the liquid is the making and breaking of hydrogen bonds. This dynamics, however, is far from being completely understood. Experiments such as infrared absorption and Raman scattering [2], depolarized light scattering [3], and inelastic neutron scatterin...

The title compound, C(4)H(10)N(3)O(2)(+) x C(2)H(2)NO(3)(-) x C(2)H(3)NO(3), contains at least 11 distinct hydrogen-bond interactions showing a great variety of bond strengths. The shortest and strongest hydrogen bond [O...O = 2.5004 (12) A] is found between the uncharged oxamic acid molecule and the oxamate monoanion. The grouping formed by such a strong hydrogen bond can thus be considered as...

A hydrogen bond for a local-minimum-energy structure can be identified according to the definition of the International Union of Pure and Applied Chemistry (IUPAC recommendation 2011) or by finding a special bond critical point on the density map of the structure in the framework of the atoms-in-molecules theory. Nonetheless, a given structural conformation may be simply favored by electrostati...

Anabaena apoflavodoxin contains a single histidine residue (H34) that interacts with two aromatic residues (F7 and Y47). The histidine and phenylalanine rings are almost coplanar and they can establish a cation-pi interaction when the histidine is protonated. The histidine and tyrosine side-chains are engaged in a hydrogen bond, which is their only contact. We analyse the energetics of these in...

Stereo-selectively synthesized 1,3-poly-alcohols are introduced as low-dimensional spectroscopic model systems for molecular dynamics in hydrogen-bonded networks. The molecular and vibrational structures of the artificial networks are studied by means of density functional theory. The flexibility of the networks and the time scales associated with hydrogen-bond breakage and formation are invest...