SPECTROSCOPIC STUDIES OF ALCOHOLS: VI. INTRAMOLECULAR HYDROGEN BONDS IN ETHANOLAMINE AND ITS O- AND N-METHYL DERIVATIVES

1965 ◽  
Vol 43 (11) ◽  
pp. 2970-2977 ◽  
Author(s):  
P. J. Krueger ◽  
H. D. Mettee
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Temperature Dependence ◽  
Spectroscopic Studies ◽  
Intramolecular Hydrogen Bonds ◽  
Distinct Band ◽  
Conformational Equilibria ◽  
Methyl Derivatives ◽  
Intramolecular Hydrogen

The competitive intramolecular [Formula: see text] hydrogen bonding in ethanolamine and N-methylethanolamine has been studied in dilute C2Cl4 solution by means of the temperature dependence of the fundamental OH and NH stretching bands. Of the three conformers identified for each of these compounds, the least stable shows a distinct band which is assigned to a "terminal" OH group involved in an intramolecular [Formula: see text] hydrogen bond. Enthalpy differences between conformers are reported and discussed, and compared with those found for the conformational equilibria in 2-methoxyethylamine and N,N-dimethyl-ethanolamine.

Halogen Bonding Organocatalysis Enhanced through Intramolecular Hydrogen Bonds

2022 ◽  
Author(s):  
Asia Marie S Riel ◽  
Daniel Adam Decato ◽  
Jiyu Sun ◽  
Orion Berryman
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Halogen Bond ◽  
Direct Interaction ◽  
Halogen Bonding ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen

Recent results indicate a halogen bond donor is strengthened through direct interaction with a hydrogen bond to the electron-rich belt of the halogen. Here, this Hydrogen Bond enhanced Halogen Bond...

Intramolecular hydrogen bonds and the orientation of amino groupsin o-phenylenediamines

1967 ◽  
Vol 45 (19) ◽  
pp. 2135-2141 ◽  
Author(s):  
P. J. Krueger
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Infrared Absorption ◽  
Substituent Effect ◽  
Proton Donor ◽  
Proton Acceptor ◽  
Amino Groups ◽  
Intramolecular Hydrogen Bonds ◽  
Infrared Absorption Spectra ◽  
Intramolecular Hydrogen

The infrared absorption spectra of partially deuterated o-phenylenediamine and 4,5-di-methyl-, 4-methyl-, and 4-chloro-o-phenylenediamine in dilute CCl4 solution show double intramolecular [Formula: see text] hydrogen bonds in which the two NHD groups are equivalent and each group acts as both a proton donor and a proton acceptor. The ring substituent effect on this interaction in these compounds is small. In 4-methoxy-o-phenylenediamine, the amino groups are not equivalent, but double intramolecular hydrogen bonds are still present. In 4-nitro-o-phenylenediamine, only one intramolecular [Formula: see text] hydrogen bond appears to exist. The effect of N-substitution on some of these observations is discussed.

Intra- and inter-molecular hydrogen bonding in diphytanylglycerol phospholipids: an infrared spectroscopic investigation

1990 ◽  
Vol 68 (1) ◽  
pp. 266-273 ◽  
Author(s):  
L. C. Stewart ◽  
M. Kates ◽  
P. W. Yang ◽  
H. H. Mantsch
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bond ◽  
Membrane Lipids ◽  
Head Group ◽  
Exact Nature ◽  
Oh Groups ◽  
Intramolecular Hydrogen ◽  
Phosphate Groups

A series of diphytanylglycerol phospholipids, i.e., diphytanylglycerol phosphate (PA), diphytanylglycerol phosphoglycerophosphate (PGP), the tri- and tetra-methyl derivatives of PGP, and the 2-deoxyglycerol analogue of PGP (dPGP) were studied by Fourier transform infrared spectroscopy. The use of the "deoxy" and methylated analogues of PGP, as well as that of PA and PGP of varying degrees of ionization, allowed the assignment of characteristic infrared bands associated with the phosphate groups. Analysis of these phosphate bands showed that at neutral pH, each of the two phosphate moieties in PGP is singly ionized, whereas in dPGP the phosphomonoester is doubly ionized. This is a consequence of the marked increase in the pK of one of the P-OH groups on the terminal phosphate of PGP (pK > 11), owing to the formation of an intramolecular hydrogen bond between the head group glycerol hydroxyl and the phosphate groups of PGP. Such an intramolecular hydrogen bond can not be formed by the dPGP analogue, and thus both negative charges in dPGP are located at the terminal phosphomonoester group. The O=P—OH groups of PGP also forms a network of intermolecular hydrogen bonds, the exact nature of which depends on concentration and degree of ionization. The possibility of a complex network of hydrogen bonds within (intramolecular) and between (intermolecular) anionic membrane lipids such as that found in PGP, is consistent with the hypothesis that these lipids function as proton-conducting pathways in membranes.Key words: phospholipids, infrared, hydrogen bonding, phosphatidylglycerophosphate, 2-deoxyphosphatidylglycerophosphate.

Temperature dependence of chemical shifts of protons in hydrogen bonds. Experimental evidence on an intramolecular hydrogen bond

1968 ◽  
Vol 46 (17) ◽  
pp. 2865-2868 ◽  
Author(s):  
T. Schaefer ◽  
G. Kotowycz
Keyword(s):  
Hydrogen Bond ◽  
Carbon Tetrachloride ◽  
Chemical Shift ◽  
Hydrogen Bonds ◽  
Temperature Dependence ◽  
Intramolecular Hydrogen Bond ◽  
Chemical Shifts ◽  
Hydroxyl Proton ◽  
Intramolecular Hydrogen ◽  
Strong Intramolecular Hydrogen Bond

A temperature dependence of the chemical shift of the hydroxyl proton in the strong intramolecular hydrogen bond in 3,5-dichlorosalicylaldehyde is observed in carbon tetrachloride and benzene-d6 solutions. Its magnitude of 0.25 to 0.30 × 10−2 p.p.m. per ° C over a range of 100 °C is in agreement with the model described by Muller and Reiter (1).

scholarly journals Interactions of Aggregating Peptides Probed by IR-UV Action Spectroscopy

2018 ◽  
Author(s):  
Sjors Bakels ◽  
E.M. Meijer ◽  
Mart Greuell ◽  
Sebastiaan Porskamp ◽  
George Rouwhorst ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Self Assembly ◽  
Intermolecular Hydrogen Bond ◽  
Beta Sheet ◽  
Dispersion Interactions ◽  
Intramolecular Hydrogen Bonds ◽  
Action Spectroscopy ◽  
Hydrogen Bond Interactions ◽  
Intramolecular Hydrogen

Peptide aggregation, the self-assembly of peptides into structured beta-sheet fibril structures, is driven by a combination of intra- and intermolecular interactions. Here, the interplay between intramolecular and formed inter-sheet hydrogen bonds and the effect of dispersion interactions on the formation of neutral, isolated, peptide dimers is studied by infrared action spectroscopy. Therefore, four different homo- and hetereogeneous dimers formed from three different alanine-based model peptides have been studied under controlled and isolated conditions. The peptides differ from one another in the presence and location of a UV chromophore containing cap on either the C- or N-terminus. Conformations of the monomers of the peptides direct the final dimer structure: strongly hydrogen bonded or folded structures result in weakly bound dimers. Here the intramolecular hydrogen bonds are favored over new intermolecular hydrogen bond interactions. In contrast, linearly folded monomers are the ideal template to form parallel beta-sheet type structures. The weak intramolecular hydrogen bonds present in the linear monomers are replaced by the stronger inter-sheet hydrogen bond interactions. The influence of π-π disperion interactions on the structure of the dimer is minimal, the phenyl rings have the tendency to fold away from the peptide backbone to favour intermolecular hydrogen bond interactions. Quantum chemical calculations confirm our experimental observations.

scholarly journals Synthesis and Heterocyclization of 4-Hydroxy-3 - ((2-hydroxy-4,4-dimethyl-6-oxocyclohex1-en-1-yl) (aryl) methyl) -2H-chromen-2-ones

2020 ◽  
Vol 20 (4) ◽  
pp. 362-371
Author(s):  
Alexander Yu. Kostritskiy ◽  
◽  
Marina G. Nakonechnikova ◽  
Olga V. Fedotova ◽  
Nina V. Pchelintseva ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
13C Nmr ◽  
Intermediate Complex ◽  
Intramolecular Hydrogen Bonds ◽  
Propionic Anhydride ◽  
Intramolecular Hydrogen ◽  
Aryl Methyl

The possibility of obtaining asymmetric 1,5-diketones based on 4-hydroxy-2H-chromen-2-one and dimedone by three-component condensation in the presence of L-proline as a catalyst is shown. As a result, a series of 4-hydroxy3 - ((2-hydroxy-4,4-dimethyl-6-oxocyclohex1-en-1-yl) (aryl) methyl) -2H-chromen-2-ones was obtained with a yield of 25 up to 73%. The study revealed that the highest yield was observed for compounds containing fragments of ortho-substituted aldehydes capable of forming a hydrogen bond. For meta- and para-substituted – the lowest yield was observed. In the case of ortho-substitution this can be probably explained due to the stabilization of the intermediate complex by two intramolecular hydrogen bonds, which makes it possible to selectively obtain only one final product – 4-hydroxy-3 -((2-hydroxy4,4-dimethyl-6-oxocyclohex-1- en-1-yl) (aryl) methyl) -2Hchromen-2-one. The structure of the obtained products was confirmed by 1 H, 13C NMR, HSQC, HMBC spectroscopy. Considering the 1,5-diketone fragment for the above-described compounds, the possibility of their O-heterocyclization by propionic anhydride was suggested. Boiling 4-hydroxy-3 - ((2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl) (aryl) methyl) -2Hchromen-2-ones in anhydride medium for an hour resulted in obtaining a series of 7- (aryl) -10,10-dimethyl-7,9,10,11-tetrahydro-6H, 8H-chromeno [4,3-b] chromene-6,8-diones. Their structure was also confirmed by 1 H, 13C NMR, HSQC, HMBC spectroscopy.

NUCLEAR SHIELDING PARAMETERS FOR PROTONS IN HYDROGEN BONDS: II. CORRELATION OF CHEMICAL SHIFTS IN INTRAMOLECULAR HYDROGEN BONDS WITH INFRARED STRETCHING FREQUENCIES

1960 ◽  
Vol 38 (8) ◽  
pp. 1249-1254 ◽  
Author(s):  
L. W. Reeves ◽  
E. A. Allan ◽  
K. O. Strømme
Keyword(s):  
Hydrogen Bond ◽  
Chemical Shift ◽  
Hydrogen Bonds ◽  
Infinite Dilution ◽  
Chemical Shifts ◽  
Intramolecular Hydrogen Bonds ◽  
A Value ◽  
Nuclear Shielding ◽  
Intramolecular Hydrogen ◽  
Hydrogen Bonded

Nuclear shielding parameters have been obtained for 24 intramolecularly hydrogen-bonded phenols and naphthols. The shielding parameters are corrected for large diamagnetic anisotropies and a value ΔσOH obtained which represents the change in shielding parameter in parts per million with reference to the infinite dilution chemical shift of phenol, α-naphthol, or β-naphthol. These values of ΔσOH are approximately proportional to the change ΔvOH in the OH stretching frequency on formation of the hydrogen bond.

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