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.

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.

scholarly journals Microscopic Structural Features of Water in Aqueous-Reline Mixture of Varying Composition

2020 ◽  
Author(s):  
Soham Sarkar ◽  
Atanu Maity ◽  
Rajarshi Chakrabarti
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Choline Chloride ◽  
Bond Formation ◽  
Orientational Order ◽  
Water Structure ◽  
Structural Features ◽  
Water Molecules ◽  
Hydrogen Bond Formation ◽  
Hydrogen Bonded

Reline, a mixture of urea and choline chloride in 2:1 molar ratio, is one of the most frequently used deep eutectic solvents. Pure reline and its aqueous solution have large scale industrial use. Owing to the presence of active hydrogen bond formation sites, urea and choline cation can disrupt the hydrogen-bonded network in water. However, a quantitative understanding of the microscopic structural features of water in the presence of reline is still lacking. We use extensive all-atom molecular dynamics simulations to elucidate the effect of the gradual addition of co-solvents on microscopic arrangements of water molecules. We consider four aqueous solutions of reline, between the wt% 26.3 to 91.4. A disruption of the local hydrogen-bonded water structure is observed on inclusion of urea and choline chloride. The extent of deviation of water structure from tetrahedrality is quantified using the orientational order parameter. Our analyses show a monotonic increase in structural disorder as the co-solvents are added. Increment in the values are observed when highly electro-negative hetero-atoms like Nitrogen, Oxygen of urea and choline cations are counted as the partners of the central water molecules. Further insights are drawn from the characterization of the hydrogen-bonded network of the water and we observe gradual rupturing of water-water hydrogen bonds and its subsequent replacement by the water-urea hydrogen bonds. A negligible contribution from the hydrogen bonds between water and bulky choline cation has also been found. Considering all the constituents as the hydrogen bond partner we calculate the possibility of successful hydrogen bond formation with a central water molecule. This gives a clear picture of the underlying mechanism of water replacement by urea.

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.

Molecular recognition studies of selected isoalloxazines with 2,6-diamidopyridine derivatives

2005 ◽  
Vol 2005 (11) ◽  
pp. 719-723 ◽  
Author(s):  
Geetanjali ◽  
Ram Singh ◽  
Shive Murat Singh Chauhan
Keyword(s):  
Hydrogen Bond ◽  
Molecular Recognition ◽  
Bond Formation ◽  
Hydrogen Bond Formation ◽  
Metal Free ◽  
Disulfide Formation ◽  
Pyridine Complex ◽  
Hydrogen Bonded

Triple hydrogen bond formation towards the uracil moiety of an isoalloxazine ring with 2,6-diamidopyridine derivatives has been observed in chloroform. A hydrogen bonded isoalloxazine–pyridine complex has been successfully utilised in disulfide formation as a metal-free organocatalyst.

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