On the Hydrogen Bond Breaking Ability of Fluorocarbons Containing Higher Halogens

1974 ◽  
Vol 52 (21) ◽  
pp. 3612-3622 ◽  
Author(s):  
Thérèse Di Paolo ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Bond Breaking ◽  
Anesthetic Activity ◽  
Competitive Mechanism ◽  
Infrared Measurements ◽  
Donor Acceptor

Infrared measurements show that fluorocarbons containing higher halogens are able to open O—H---O, N—H---N, S—H---S, N—H---O=C, type hydrogen bonds. This is probably due to a competitive mechanism of association consisting in the formation of donor–acceptor complexes. It is suggested that the breaking or perturbation of hydrogen bonds by this mechanism is of importance for the explanation of the anesthetic activity of these compounds.

Anesthesia and hydrogen bonding. A semi-quantitative infrared study at room temperature

1978 ◽  
Vol 56 (12) ◽  
pp. 1681-1686 ◽  
Author(s):  
Ginette Trudeau ◽  
K. C. Cole ◽  
Rachel Massuda ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Quantitative Relationship ◽  
Bond Breaking ◽  
Infrared Study ◽  
Text Types ◽  
Theories Of Anesthesia ◽  
Anesthetic Potency

It has been shown previously that certain anesthetics hinder the formation of hydrogen bonds of the [Formula: see text] types. An attempt bas now been made to correlate this hydrogen bond 'breaking' property with anesthetic potency. As a measure of the former, relative intensifies of infrared bands related to 'free' and hydrogen bonded species were used. The band which was chosen for this purpose is the OH or NH stretching + in-plane bending combination band. This made it possible to carry out the measurements at room temperature. A semi-quantitative relationship has been found. Its significance for the theories of anesthesia is discussed.

scholarly journals Investigation of the nature of hydrogen bonds in 3,5-dimethylpyrazole

2020 ◽  
Vol 61 (1) ◽  
pp. 9-13
Author(s):  
Tatiana G. Volkova ◽  
◽  
Konstantin A. Chicherin ◽  
Irina O. Talanova ◽  
◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Self Organization ◽  
Supramolecular Systems ◽  
Acceptor Interaction ◽  
Covalent Interaction ◽  
Wide Range ◽  
Main Motive ◽  
Donor Acceptor ◽  
Hydrogen Bound

Compounds containing a pyrazole fragment in their structure are part of many medicines and have a wide range of bioactivity (for example, antimicrobial, anti-tuberculosis, etc.), and are also successfully used for the development of various synthetic anti-tumor agents. Interest in them is also caused by the presence of hydrogen bonds, which are the main motive for self-organization of molecules. A theoretical study of the nature of hydrogen bonds in various hydrogen-bound motifs in 3,5-dimethylpyrazole was performed using the DFT/B3LYP/6-31G(d,p) method. The results obtained indicate the possible existence of dimeric, trimeric, and tetrameric cyclic forms. Geometric and energy parameters of hydrogen bonds N-H...N are determined and the energies of donor-acceptor interaction in possible forms of self-organization of the molecules of the studied compound are calculated. It has been established that the hydrogen bond (H-bond) is the result of the interaction of a hybrid unshielded pair of a nitrogen atom of one molecule and a loosening natural orbital between the nitrogen atoms of one molecule and the hydrogen of another molecule (σ* N-H). The formation of the binding σ-orbital of the H-bond indicates the predominance of covalent interaction in the hydrogen bond. The study and analysis of the results showed that the formation of supramolecular systems of 3,5-dimethylpyrazole most likely structures are trimers and tetramers.

scholarly journals Crystal structure of the 1,3,6,8-tetraazatricyclo[4.3.1.13,8]undecane (TATU)–4-nitrophenol (1/2) adduct: the role of anomeric effect in the formation of a second hydrogen-bond interaction

2015 ◽  
Vol 71 (11) ◽  
pp. 1356-1360 ◽  
Author(s):  
Augusto Rivera ◽  
Héctor Jairo Osorio ◽  
Juan Manuel Uribe ◽  
Jaime Ríos-Motta ◽  
Michael Bolte
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Normal Donor ◽  
Anomeric Effect ◽  
Hydrogen Bond Interaction ◽  
Hydrogen Bond Formation ◽  
Dimensional Network ◽  
Crystalline Adduct ◽  
Donor Acceptor

In the title ternary co-crystalline adduct, C7H14N4·2C6H5NO3, molecules are linked by two intermolecular O—H...N hydrogen bonds, forming a tricomponent aggregates in the asymmetric unit. The hydrogen-bond formation to one of the N atoms is enough to induce structural stereoelectronic effects in the normal donor→acceptor direction. In the title adduct, the two independent nitrophenol molecules are essentially planar, with maximum deviations of 0.0157 (13) and 0.0039 (13) Å. The dihedral angles between the planes of the nitro group and the attached benzene rings are 4.04 (17) and 5.79 (17)°. In the crystal, aggregates are connected by C—H...O hydrogen bonds, forming a supramolecular dimer enclosing anR66(32) ring motif. Additional C—H...O intermolecular hydrogen-bonding interactions form a second supramolecular inversion dimer with anR22(10) motif. These units are linkedviaC—H...O and C—H...N hydrogen bonds, forming a three-dimensional network.

scholarly journals Sodium sulfite heptahydrate and its relation to sodium carbonate heptahydrate

2020 ◽  
Vol 76 (5) ◽  
pp. 427-432
Author(s):  
Matthias Weil ◽  
Kurt Mereiter
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Sodium Sulfite ◽  
Monoclinic Crystal ◽  
Organic Sulfur Compounds ◽  
Monoclinic Crystal Structure ◽  
Structural Relationships ◽  
Water Layers ◽  
Donor Acceptor

The monoclinic crystal structure of Na2SO3(H2O)7 is characterized by an alternating stacking of (100) cationic sodium–water layers and anionic sulfite layers along [100]. The cationic layers are made up from two types of [Na(H2O)6] octahedra that form linear 1 ∞[Na(H2O)4/2(H2O)2/1] chains linked by dimeric [Na(H2O)2/2(H2O)4/1]2 units on both sides of the chains. The isolated trigonal–pyramidal sulfite anions are connected to the cationic layers through an intricate network of O—H...O hydrogen bonds, together with a remarkable O—H...S hydrogen bond, with an O...S donor–acceptor distance of 3.2582 (6) Å, which is about 0.05 Å shorter than the average for O—H...S hydrogen bonds in thiosalt hydrates and organic sulfur compounds of the type Y—S—Z (Y/Z = C, N, O or S). Structural relationships between monoclinic Na2SO3(H2O)7 and orthorhombic Na2CO3(H2O)7 are discussed in detail.

The Influence of Small Monovalent Cations on Neighbouring Hydrogen Bonds of Aquo-Protein Complexes

1981 ◽  
Vol 36 (12) ◽  
pp. 1357-1360 ◽  
Author(s):  
Kritsana P. Sagarik ◽  
Bernd M. Rode
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Metal Ion ◽  
Protein Complexes ◽  
Basis Sets ◽  
Monovalent Cations ◽  
Hydrogen Bond Energy ◽  
Acceptor Interaction ◽  
Monovalent Metal ◽  
Donor Acceptor

AbstractThe influence of small monovalent metal ions on hydrogen bonds of aquo-protein complexes is studied on Li+/HCONH2-OH2 as an example. Using results obtained from ab initio calculations with minimal GLO basis sets, the remarkable changes in the hydrogen bond energy and charge distribution, due to metal ion complex formation, are discussed. The metal ion seems to enhance strongly the donor-acceptor interaction of the O ... H-N-C=0 hydrogen-bonded system.

scholarly journals Fluctuating hydrogen-bond networks govern anomalous electron transfer kinetics in a blue copper protein

2018 ◽  
Vol 115 (24) ◽  
pp. 6129-6134 ◽  
Author(s):  
Joshua S. Kretchmer ◽  
Nicholas Boekelheide ◽  
Jeffrey J. Warren ◽  
Jay R. Winkler ◽  
Harry B. Gray ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Electron Transfer ◽  
Hydrogen Bonds ◽  
Long Range ◽  
Driving Forces ◽  
Reorganization Energy ◽  
Electronic Coupling ◽  
Hydrogen Bond Networks ◽  
Donor Acceptor ◽  
Network Of Hydrogen Bonds

We combine experimental and computational methods to address the anomalous kinetics of long-range electron transfer (ET) in mutants of Pseudomonas aeruginosa azurin. ET rates and driving forces for wild type (WT) and three N47X mutants (X = L, S, and D) of Ru(2,2′-bipyridine)2 (imidazole)(His83) azurin are reported. An enhanced ET rate for the N47L mutant suggests either an increase of the donor–acceptor (DA) electronic coupling or a decrease in the reorganization energy for the reaction. The underlying atomistic features are investigated using a recently developed nonadiabatic molecular dynamics method to simulate ET in each of the azurin mutants, revealing unexpected aspects of DA electronic coupling. In particular, WT azurin and all studied mutants exhibit more DA compression during ET (>2 Å) than previously recognized. Moreover, it is found that DA compression involves an extended network of hydrogen bonds, the fluctuations of which gate the ET reaction, such that DA compression is facilitated by transiently rupturing hydrogen bonds. It is found that the N47L mutant intrinsically disrupts this hydrogen-bond network, enabling particularly facile DA compression. This work, which reveals the surprisingly fluctional nature of ET in azurin, suggests that hydrogen-bond networks can modulate the efficiency of long-range biological ET.

The influence of pressure on the infrared spectra of hydrogen-bonded solids. III. Compounds with N-H...X bonds

1976 ◽  
Vol 29 (8) ◽  
pp. 1641 ◽  
Author(s):  
SD Hamann ◽  
M Linton
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Infrared Measurements ◽  
Hydrogen Bonded

Infrared measurements have been made of the influence of pressures between 0 and 40 kbar on the stretching and bending frequencies of N-H groups in a range of crystalline compounds which have N-H. . .N, N-H. . .O, N-H. . .S or N-H. . .Cl hydrogen bonds. The frequencies have been found to change in accordance with rules that were derived and tested in Parts I and I1 for other kinds of hydrogen-bond systems.

Synthesis and Structural Characterization of Diisopropylammonium Trifluoroacetate and Diisoproplyammonium Pentafluoropropionate

2010 ◽  
Vol 65 (4) ◽  
pp. 479-484 ◽  
Author(s):  
Guido J. Reiß ◽  
Michaela K. Meyer
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Van Der Waals Interactions ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Donor Acceptor ◽  
Double Hydrogen

Diisopropylammonium trifluoroacetate ({[iPr2NH2][CF3COO]}; dip tfa; 1) and diisopropylammonium pentafluoropropionate ({[iPr2NH2][C2F5COO]}; dip pfp; 2) have been synthesized and structurally characterized by X-ray diffraction and spectroscopic methods. Both compounds form hydrogen-bonded cyclic dimers (Etter symbol: R44 (12)) in the solid state. The asymmetric unit of 1 contains one trifluoroacetate anion and one dip cation in the centrosymmetric space group Pī. The asymmetric unit of 2 consists of two crystallographically independent pentafluoropropionate anions and two independent dip cations forming dimers in the form of rings, both lying around centers of symmetry in the space group Pī. In dip tfa and dip pfp the cations act as double hydrogen bond donors, and each of the two oxygen atoms of the carboxyl group are single hydrogen bond acceptors. The donor acceptor distances of the N-H...O hydrogen bonds are within the expected range for medium strong hydrogen bonds. The quasi-molecular cyclic dimers are connected with neighboring units only by van der Waals interactions.

Hydrogen bonds in N-(3-chloro-2-benzo[b]thienocarbonyl)- and N-(2-benzo[b]thienocarbonyl)-N'-monosubstituted thioureas

1987 ◽  
Vol 52 (11) ◽  
pp. 2673-2679 ◽  
Author(s):  
Oľga Hritzová ◽  
Peter Kutschy ◽  
Ján Imrich ◽  
Thomas Schöffmann
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Strong Hydrogen Bond ◽  
Cyclic Form ◽  
Thiourea Derivatives

N-(3-Chloro-2-benzo[b]thienocarbonyl)-N'-monosubstituted thiourea derivatives undergo photocyclizations with lower yields than those obtained from analogous N',N'-disubstituted derivatives. This decreased reactivity is caused by the existence of a six-membered cyclic form with the very strong hydrogen bond NH···O=C. The possibility of formation of various conformers has been found with N-(2-benzo[b]thienocarbonyl)-N'-monosubstituted thiourea derivatives as a consequence of the rotation around the C(2)-C(O) connecting line.

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