scholarly journals Femtosecond Mid-Infrared Spectroscopy of Hydrogen-Bonded Liquids

1999 ◽  
Vol 19 (1-4) ◽  
pp. 83-90 ◽  
Author(s):  
S. Woutersen ◽  
U. Emmerichs ◽  
H. J. Bakker
Keyword(s):  
Hydrogen Bond ◽  
Infrared Spectroscopy ◽  
Hydrogen Bonds ◽  
Pump Probe ◽  
Mid Infrared ◽  
Hydrogen Bond Strength ◽  
Stretching Vibration ◽  
Probe Spectroscopy ◽  
Femtosecond Time Scale ◽  
Hydrogen Bonded

We perform femtosecond mid-infrared pump-probe spectroscopy on hydrogen-bonded ethanol dissolved in CCl4. We find that upon excitation of the OH-stretching vibration the hydrogen bonds are predissociated on a femtosecond time scale, and that the predissociation time constant depends strongly on the hydrogen-bond strength.

scholarly journals Di-μ-chlorido-bis[(2,2′-bipyridine-5,5′-dicarboxylic acid-κ2N,N′)chloridocopper(II)] dimethylformamide tetrasolvate

2013 ◽  
Vol 69 (2) ◽  
pp. m73-m74 ◽  
Author(s):  
Sigurd Øien ◽  
David Stephen Wragg ◽  
Karl Petter Lillerud ◽  
Mats Tilset
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Cooh Group ◽  
Stacking Interactions ◽  
Coordination Geometry ◽  
Complex Molecules ◽  
Centroid Distance ◽  
Solvent Molecules ◽  
Hydrogen Bonded

In the title compound, [Cu2Cl4(C12H8N2O4)2]·4C3H7NO, which contains a chloride-bridged centrosymmetric CuIIdimer, the CuIIatom is in a distorted square-pyramidal 4 + 1 coordination geometry defined by the N atoms of the chelating 2,2′-bipyridine ligand, a terminal chloride and two bridging chloride ligands. Of the two independent dimethylformamide molecules, one is hydrogen bonded to a single –COOH group, while one links two adjacent –COOH groupsviaa strong accepted O—H...O and a weak donated C(O)—H...O hydrogen bond. Two of these last molecules and the two –COOH groups form a centrosymmetric hydrogen-bonded ring in which the CH=O and the –COOH groups by disorder adopt two alternate orientations in a 0.44:0.56 ratio. These hydrogen bonds link the CuIIcomplex molecules and the dimethylformamide solvent molecules into infinite chains along [-111]. Slipped π–π stacking interactions between two centrosymmetric pyridine rings (centroid–centroid distance = 3.63 Å) contribute to the coherence of the structure along [0-11].

Redshift or Adduct Stabilization—A Computational Study of Hydrogen Bonding in Adducts of Protonated Carboxylic Acids

2009 ◽  
Vol 15 (2) ◽  
pp. 239-248 ◽  
Author(s):  
Solveig Gaarn Olesen ◽  
Steen Hammerum
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Bond Strength ◽  
Bond Length ◽  
Carboxylic Acids ◽  
Computational Study ◽  
Proton Affinities ◽  
Oh Groups ◽  
Hydrogen Bond Strength ◽  
Length Changes

It is generally expected that the hydrogen bond strength in a D–H•••A adduct is predicted by the difference between the proton affinities (Δ PA) of D and A, measured by the adduct stabilization, and demonstrated by the infrared (IR) redshift of the D–H bond stretching vibrational frequency. These criteria do not always yield consistent predictions, as illustrated by the hydrogen bonds formed by the E and Z OH groups of protonated carboxylic acids. The Δ PA and the stabilization of a series of hydrogen bonded adducts indicate that the E OH group forms the stronger hydrogen bonds, whereas the bond length changes and the redshift favor the Z OH group, matching the results of NBO and AIM calculations. This reflects that the thermochemistry of adduct formation is not a good measure of the hydrogen bond strength in charged adducts, and that the ionic interactions in the E and Z adducts of protonated carboxylic acids are different. The OH bond length and IR redshift afford the better measure of hydrogen bond strength.

scholarly journals Study on the unsaturated hydrogen bond behavior of bio-based polyamide 56

e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 23-31
Author(s):  
Shouyun Zhang ◽  
Jinghong Ma
Keyword(s):  
Hydrogen Bond ◽  
Infrared Spectroscopy ◽  
Hydrogen Bonds ◽  
Metal Oxides ◽  
Significant Influence ◽  
Polymer Chains ◽  
Experimental Results ◽  
Bond Behavior ◽  
Unit Structure

AbstractIn this paper, the unsaturated hydrogen bonds (H-bonds) of the bio-based polyamide 56 (PA56) with an odd-even unit structure were analyzed by infrared spectroscopy. It was proved that the bio-based PA56 had less saturated H-bonds, which became attenuated and blue-shifted at the temperature exceeding 260°C. Besides, as H-bond was decayed and broken, new unsaturated H-bonds readily formed. Moreover, the experimental results obtained strongly indicate that the unsaturated H-bonds of bio-based polyamide 56 could react with polar metal oxides. Besides, the intercalation of montmorillonite was found to have a significant influence on the hydrogen bond between polymer chains.

Two polymorphs and the diethylammonium salt of the barbiturate eldoral

2012 ◽  
Vol 68 (2) ◽  
pp. o65-o70 ◽  
Author(s):  
Thomas Gelbrich ◽  
Denise Rossi ◽  
Ulrich J. Griesser
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Barbituric Acid ◽  
Layer Structure ◽  
Chain Structure ◽  
Hydrogen Bond Acceptor ◽  
Layer Structures ◽  
A Chain ◽  
Derivatives Of ◽  
Hydrogen Bonded

Polymorph (Ia) of eldoral [5-ethyl-5-(piperidin-1-yl)barbituric acid or 5-ethyl-5-(piperidin-1-yl)-1,3-diazinane-2,4,6-trione], C11H17N3O3, displays a hydrogen-bonded layer structure parallel to (100). The piperidine N atom and the barbiturate carbonyl group in the 2-position are utilized in N—H...N and N—H...O=C hydrogen bonds, respectively. The structure of polymorph (Ib) contains pseudosymmetry elements. The two independent molecules of (Ib) are connectedviaN—H...O=C(4/6-position) and N—H...N(piperidine) hydrogen bonds to give a chain structure in the [100] direction. The hydrogen-bonded layers, parallel to (010), formed in the salt diethylammonium 5-ethyl-5-(piperidin-1-yl)barbiturate [or diethylammonium 5-ethyl-2,4,6-trioxo-5-(piperidin-1-yl)-1,3-diazinan-1-ide], C4H12N+·C11H16N3O3−, (II), closely resemble the corresponding hydrogen-bonded structure in polymorph (Ia). Like many other 5,5-disubstituted derivatives of barbituric acid, polymorphs (Ia) and (Ib) contain theR22(8) N—H...O=C hydrogen-bond motif. However, the overall hydrogen-bonded chain and layer structures of (Ia) and (Ib) are unique because of the involvement of the hydrogen-bond acceptor function in the piperidine group.

Two methyl 3-(1H-pyrazol-4-yl)octahydropyrrolo[3,4-c]pyrrole-1-carboxylates form different hydrogen-bonded sheets

2013 ◽  
Vol 69 (8) ◽  
pp. 915-919
Author(s):  
Jairo Quiroga ◽  
Jaime Gálvez ◽  
Justo Cobo ◽  
Christopher Glidewell
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Hydrogen Bonded

In the molecules of both methyl (1RS,3SR,3aRS,6aSR)-1-methyl-3-(3-methyl-1-phenyl-1H-pyrazol-4-yl)-4,6-dioxo-5-phenyloctahydropyrrolo[3,4-c]pyrrole-1-carboxylate, C25H24N4O4, (I), and methyl (1RS,3SR,3aRS,6aSR)-5-(4-chlorophenyl)-1-methyl-3-(3-methyl-1-phenyl-1H-pyrazol-4-yl)-4,6-dioxooctahydropyrrolo[3,4-c]pyrrole-1-carboxylate, C25H23ClN4O4, (II), the two rings of the pyrrolopyrrole fragment are both nonplanar, with conformations close to half-chair forms. The overall conformations of the molecules of (I) and (II) are very similar, apart from the orientation of the ester function. The molecules of (I) are linked into sheets by a combination of an N—H...π(pyrrole) hydrogen bond and three independent C—H...O hydrogen bonds. The molecules of (II) are also linked into sheets, which are generated by a combination of an N—H...N hydrogen bond and two independent C—H...O hydrogen bonds, weakly augmented by a C—H...π(arene) hydrogen bond.

scholarly journals (2E)-3-(6-Methoxynaphthalen-2-yl)-1-(pyridin-3-yl)prop-2-en-1-one and its cyclocondensation product with guanidine, (4RS)-2-amino-4-(6-methoxynaphthalen-2-yl)-6-(pyridin-3-yl)-3,4-dihydropyrimidine monohydrate: two types of hydrogen-bonded sheet

2014 ◽  
Vol 70 (11) ◽  
pp. 1011-1016 ◽  
Author(s):  
Prakash S. Nayak ◽  
Badiadka Narayana ◽  
Hemmige S. Yathirajan ◽  
Eric C. Hosten ◽  
Richard Betz ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Dihedral Angles ◽  
Form Complex ◽  
Molecular Components ◽  
Hydrogen Bonded

The structures of a chalcone and of its cyclocondensation product with guanidine are reported. In (2E)-3-(6-methoxynaphthalen-2-yl)-1-(pyridin-3-yl)prop-2-en-1-one, C19H15NO2, (I), the planes of the pyridine and naphthalene units make dihedral angles with that of the central spacer unit of 23.61 (13) and 23.57 (15)°, respectively, and a dihedral angle of 47.24 (9)° with each other. The molecules of (I) are linked into sheets by a combination of C—H...O and C—H...π(arene) hydrogen bonds. In the cyclocondensation product (4RS)-2-amino-4-(6-methoxynaphthalen-2-yl)-6-(pyridin-3-yl)-3,4-dihydropyrimidine monohydrate, C20H18N4O·H2O, (II), the dihydropyrimidine ring adopts a conformation best described as a shallow boat. The molecular components are linked by two N—H...O hydrogen bonds, two O—H...N hydrogen bonds and one N—H...N hydrogen bond to form complex sheets, with the methoxynaphthalene interdigitated between inversion-related pairs of sheets.

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