Spectroscopic analysis and kinetics of intermolecular hydrogen bond formation in poly-pyridobisimidazole (M5) fiber

2009 ◽  
Vol 47 (18) ◽  
pp. 1809-1824 ◽  
Author(s):  
A. Andres Leal ◽  
Joseph M. Deitzel ◽  
Steven H. McKnight ◽  
John W. Gillespie
Keyword(s):  
Hydrogen Bond ◽  
Spectroscopic Analysis ◽  
Bond Formation ◽  
Intermolecular Hydrogen Bond ◽  
Hydrogen Bond Formation ◽  
Kinetics Of

Intramolecular hydrogen bonds: common motifs, probabilities of formation and implications for supramolecular organization

2000 ◽  
Vol 56 (5) ◽  
pp. 849-856 ◽  
Author(s):  
Clair Bilton ◽  
Frank H. Allen ◽  
Gregory P. Shields ◽  
Judith A. K. Howard
Keyword(s):  
Hydrogen Bond ◽  
Bond Formation ◽  
Intermolecular Hydrogen Bond ◽  
The Other ◽  
Supramolecular Organization ◽  
Intermolecular Bond ◽  
Hydrogen Bond Formation ◽  
Ability To Act ◽  
Structural Database ◽  
Intramolecular Hydrogen

A systematic survey of the Cambridge Structural Database (CSD) has identified all intramolecular hydrogen-bonded ring motifs comprising less than 20 atoms with N and O donors and acceptors. The probabilities of formation Pm of the 50 most common motifs, which chiefly comprise five- and six-membered rings, have been derived by considering the number of intramolecular motifs which could possibly form. The most probable motifs (Pm > 85%) are planar conjugated six-membered rings with a propensity for resonance-assisted hydrogen bonding and these form the shortest contacts, whilst saturated six-membered rings typically have Pm < 10%. The influence of intramolecular-motif formation on intermolecular hydrogen-bond formation has been assessed for a planar conjugated model substructure, showing that a donor-H is considerably less likely to form an intermolecular bond if it forms an intramolecular one. On the other hand, the involvement of a carbonyl acceptor in an intramolecular bond does not significantly affect its ability to act as an intermolecular acceptor and thus carbonyl acceptors display a substantially higher inclination for bifurcation if one hydrogen bond is intramolecular.

scholarly journals Excited-state intramolecular proton transfer in a bioactive flavonoid provides fluorescence observables for recognizing its engagement with target proteins

2019 ◽  
Vol 18 (9) ◽  
pp. 2270-2280 ◽  
Author(s):  
Davide Vanossi ◽  
Monica Caselli ◽  
Giorgia Pavesi ◽  
Chiara Borsari ◽  
Pasquale Linciano ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Excited State ◽  
Proton Transfer ◽  
Bond Formation ◽  
Intermolecular Hydrogen Bond ◽  
Intramolecular Proton Transfer ◽  
Hydrogen Bond Formation ◽  
Target Proteins ◽  
Emission Properties

Intra- vs. intermolecular hydrogen-bond formation and ESIPT in a bioactive flavonoid result in different emission properties and provide a clue for recognizing its binding to target proteins.

Optical and electron paramagnetic resonance studies of the excited triplet states of UV-B absorbers: 2-ethylhexyl salicylate and homomenthyl salicylate

2015 ◽  
Vol 14 (9) ◽  
pp. 1651-1659 ◽  
Author(s):  
Kazuto Sugiyama ◽  
Takumi Tsuchiya ◽  
Azusa Kikuchi ◽  
Mikio Yagi
Keyword(s):  
Hydrogen Bond ◽  
Electron Paramagnetic Resonance ◽  
Bond Formation ◽  
Intermolecular Hydrogen Bond ◽  
Triplet States ◽  
Paramagnetic Resonance ◽  
Hydrogen Bond Formation ◽  
Excited Triplet ◽  
Electron Paramagnetic ◽  
Excited Triplet States

UV-B absorbers, 2-ethylhexyl salicylate and homomenthyl salicylate, show a photoinduced phosphorescence enhancement, which originates from the photoinduced intermolecular hydrogen-bond formation.

scholarly journals Structural characterization of hydrogen bonding for antipyrine derivatives: Single-crystal X-ray diffraction and theoretical studies

2021 ◽  
Vol 16 (2) ◽  
pp. 113-137
Author(s):  
N. S. Rukk ◽  
R. S. Shamsiev ◽  
D. V. Albov ◽  
S. N. Mudretsova
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Electron Density ◽  
Bond Formation ◽  
Intermolecular Hydrogen Bond ◽  
X Ray Diffraction ◽  
Compound I ◽  
Hydrogen Bond Formation ◽  
Compound Ii

Objectives. The paper is devoted to the crystal structure characterization of 5-methyl-2-phenyl4H-pyrazol-3-one (compound I) and 2-(4-chlorophenyl)-5-methyl-4H-pyrazol-3-one (compound II).Methods. Single-crystal X-ray diffraction studies and theoretical calculations: Density functional theory and quantum theory of atoms in molecules.Results. In the solid state, the crystal structure of compound I is characterized by the alternation of OH and NH tautomers connected via O–H---O and N–H---N hydrogen bonds. For compound II, the existence of chains built from the NH monomers via hydrogen bonding can be explained by the peculiarities of cooperative effects. In the framework of quantum theory of atoms in molecules, the following topological characteristics are calculated for all dimers: electron density, Laplacian of electron density, density of kinetic, potential, and total energy in the critical point of the intermolecular hydrogen bond. It is concluded that the hydrogen bond in dimers 1–4, 7 (compound I), and 8–11 (compound II) can be assigned to the intermediate (between covalent and dispersion types) interaction owing to hydrogen bond formation with the participation of electronegative oxygen- (and/or nitrogen-) atoms, whereas H-bond in dimers 5 and 6 (compound I) can be attributed to the dispersion one (no hydrogen bond formation or weak H-bond formation), and it represents the weak interaction, being in agreement with length for intermolecular hydrogen bond in dimers. The electron density and total energy density values demonstrate that the strongest intermolecular H-bonds take place in dimers 1 (OH---O), 4 (OH---O), 7 (OH---N), 8 (OH---O), 9 (NH---N), and 11 (OH---N). The results obtained for compounds I and II are compared with data for antipyrine (1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one; compound III)Conclusions. An important role of intermolecular hydrogen bonding in the crystal packing, molecule association and self-organization via dimer- or more extended species formation has been demonstrated. 

Hydrogen bonded interactions of methanol and water with purines and pyrimidines

1983 ◽  
Vol 61 (12) ◽  
pp. 2695-2698 ◽  
Author(s):  
J. N. Spencer ◽  
S. W. Barton ◽  
K. A. Smith ◽  
W. S. Wolbach ◽  
J. F. Powell ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Bond Formation ◽  
Intermolecular Hydrogen Bond ◽  
Solvation Shell ◽  
The Self ◽  
Hydrogen Bond Formation ◽  
Interaction Site ◽  
Self Association ◽  
Purines And Pyrimidines ◽  
Hydrogen Bonded

The solvation of benzimidazole, 4-azabenzimidazole, purine, adenine, uracil, thymine, and cytosine in water and methanol was determined by a combination of calorimetric and spectral analysis. Specific enthalpies have been assigned to each interaction site in the first solvation shell. Calculations, based on the enthalpies of hydrogen bond formation with water, and estimates for intermolecular hydrogen bond enthalpies, show that the self-association of purine and adenine in water through hydrogen bonded interactions is enthalpically possible.

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