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.

3,3′-N,N′-Bis(amino)-2,2′-bipyridine — An unusually methylation-resistant amine

2011 ◽  
Vol 89 (8) ◽  
pp. 971-977
Author(s):  
Danielle M. Chisholm ◽  
Robert McDonald ◽  
J. Scott McIndoe
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Complex Mixtures ◽  
Amino Groups ◽  
Intramolecular Hydrogen Bonds ◽  
X Ray ◽  
Intramolecular Hydrogen

Methylation of aromatic amino groups is usually straightforward, but the formation of two intramolecular hydrogen bonds in 3,3′-N,N′-bis(amino)-2,2′-bipyridine and (or) the potential for ring methylation prevents the clean tetramethylation of this molecule. Numerous attempts to make 3,3′-N,N′-bis(dimethylamino)-2,2′-bipyridine produced only complex mixtures of variously methylated products, and the only isolated molecule was 3,3′-N,N′-bis(methylamino)-2,2′-bipyridine, for which an X-ray crystal structure was obtained.

scholarly journals Does the Intramolecular Hydrogen Bond Affect the Spectroscopic Properties of Bicyclic Diazole Heterocycles?

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Paweł Misiak ◽  
Alina T. Dubis ◽  
Andrzej Łapiński
Keyword(s):  
Hydrogen Bond ◽  
Quantum Theory ◽  
Intramolecular Hydrogen Bond ◽  
Natural Bond Orbital ◽  
Spectroscopic Properties ◽  
Proton Donor ◽  
Proton Acceptor ◽  
Nbo Method ◽  
Acceptor Group ◽  
Intramolecular Hydrogen

The formation of an intramolecular hydrogen bond in pyrrolo[1,2-a]pyrazin-1(2H)-one bicyclic diazoles was analyzed, and the influence of N-substitution on HB formation is discussed in this study. B3LYP/aug-cc-pVDZ calculations were performed for the diazole, and the quantum theory of atoms in molecules (QTAIM) approach as well as the natural bond orbital (NBO) method was applied to analyze the strength of this interaction. It was found that the intramolecular hydrogen bond that closes an extra ring between the C=O proton acceptor group and the CH proton donor, that is, C=O⋯H–C, influences the spectroscopic properties of pyrrolopyrazine bicyclic diazoles, particularly the carbonyl frequencies. The influence of N-substitution on the aromaticity of heterocyclic rings is also discussed in this report.

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...

Theoretical study of the substituent effect on the intramolecular hydrogen bonds in di(4-hydroxycoumarin) derivatives

2006 ◽  
Vol 106 (6) ◽  
pp. 1304-1315 ◽  
Author(s):  
Tzvetan Mihaylov ◽  
Ivelina Georgieva ◽  
Günther Bauer ◽  
Irena Kostova ◽  
Ilia Manolov ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Substituent Effect ◽  
Theoretical Study ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen

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.

Solvent effects on the infrared spectra of anilines. VII. 2-Substituted 4-nitroanilines

1970 ◽  
Vol 23 (5) ◽  
pp. 947 ◽  
Author(s):  
LK Dyall
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Solvent Effects ◽  
Intermolecular Hydrogen Bond ◽  
Lone Pair ◽  
Acceptor Molecule ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen ◽  
Ortho Substituent

Measurements of N-H stretching frequencies of 4-nitroanilines in the presence of hydrogen bond acceptors show that the ease of forming a second intermolecular hydrogen bond in the presence of an ortho substituent decreases in the order hydrogen > methyl > bromo, methoxyl > nitro. This order demonstrates the importance of repulsions between lone pair orbitals on the ortho substituent and the acceptor molecule. Weak intramolecular hydrogen bonds are detected in 2-iodo- and 2-bromo-aniline, and such bonds can be strengthened by introduction of a 4-nitro substituent.

Universal prediction of intramolecular hydrogen bonds in organic crystals

2010 ◽  
Vol 66 (2) ◽  
pp. 237-252 ◽  
Author(s):  
Peter T. A. Galek ◽  
László Fábián ◽  
Frank H. Allen
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Probability Model ◽  
Organic Crystals ◽  
Intramolecular Hydrogen Bonds ◽  
Donor And Acceptor ◽  
Universal Prediction ◽  
Structural Database ◽  
Chemical Descriptors ◽  
Intramolecular Hydrogen

A complete exploration of intramolecular hydrogen bonds (IHBs) has been undertaken using a combination of statistical analyses of the Cambridge Structural Database and computation of ab initio interaction energies for prototypical hydrogen-bonded fragments. Notable correlations have been revealed between computed energies, hydrogen-bond geometries, donor and acceptor chemistry, and frequencies of occurrence. Significantly, we find that 95% of all observed IHBs correspond to the five-, six- or seven-membered rings. Our method to predict a propensity for hydrogen-bond occurrence in a crystal has been adapted for such IHBs, applying topological and chemical descriptors derived from our findings. In contrast to intermolecular hydrogen bonding, it is found that IHBs can be predicted across the complete chemical landscape from a single optimized probability model, which is presented. Predictivity of 85% has been obtained for generic organic structures, which can exceed 90% for discrete classes of IHB.

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