Geometric conditions for the formation of short intramolecular hydrogen bonds in dicarboxylic acids and their acid salts. Crystal structures of two cyclopropane derivatives containing such bonds: ammonium hydrogen caronate and potassium hydrogen caronate hydrate

1993 ◽  
Vol 203 (2) ◽  
Author(s):  
H. Küppers ◽  
S. M. Jessen
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Dicarboxylic Acids ◽  
Intramolecular Hydrogen Bonds ◽  
Geometric Conditions ◽  
Ammonium Hydrogen ◽  
Potassium Hydrogen ◽  
Intramolecular Hydrogen ◽  
Cyclopropane Derivatives

Abstract(I) Ammonium hydrogen 3,3-dimethyl-cis-1,2-cyclopropanedicarboxylate (NHBoth compounds show short intramolecular hydrogen bonds with O…O distances of 2.477(5) Å in (I) and 2.425(3) Å in (II). The present structures complement a series of comparable chelate systems. The different geometries in these chelates influence the hydrogen bond lengths (O…O) and produce distortions of the anions to different extents. These considerations, which make the tendency to form

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.

Syntheses, Crystal Structures and an Overview of Alkali Metal Maleates

2009 ◽  
Vol 64 (5) ◽  
pp. 517-524 ◽  
Author(s):  
Michel Fleck ◽  
Ladislav Bohatý
Keyword(s):  
Hydrogen Bond ◽  
Crystal Structures ◽  
Maleic Acid ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
Hydrogen Atom Position ◽  
Potassium Hydrogen ◽  
Intramolecular Hydrogen ◽  
Atom Position

The crystal structures of four alkali salts of maleic acid have been determined by single crystal X-ray diffraction: crystals of rubidium hydrogen maleate, RbH(C4H2O4), are very nearly centrosymmetrical, i. e., only one hydrogen atom position in the crystal structure violates the centrosymmetry. Thus, the space group is Pbc21 rather than Pbcm. The compound is isotypic with potassium hydrogen maleate, KH(C4H2O4), which has previously been described in space group Pbcm. It has been reinvestigated to prove that the correct space group is also Pbc21. The isotypic pair of rubidium hydrogen maleate maleic acid, RbH(C4H2O4) H2(C4H2O4), and caesium hydrogen maleate maleic acid, CsH(C4H2O4)H2(C4H2O4), crystallise in the triclinic space group P1̄. The geometry of the maleate units in these compounds corresponds well to data of other metal maleates. The only significant variation, concerning the intra-anionic hydrogen bond, is discussed. Furthermore, an overview of previously reported metal maleate structures is given, with special regard to the symmetry of the intramolecular hydrogen bond.

Heterocyclic Tautomerism. II. 4-Acylpyrazolones. X-Ray Crystal Structures of 4-Benzoyl-5-methyl-2-phenylpyrazol-3(2H)-one and 4-Acetoacetyl-3-methyl-1-phenylpyrazol-5-ol

1985 ◽  
Vol 38 (3) ◽  
pp. 401 ◽  
Author(s):  
MJ O'Connell ◽  
CG Ramsay ◽  
PJ Steel
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Room Temperature ◽  
Crystalline Form ◽  
Intermolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen Bonds ◽  
X Ray ◽  
Intramolecular Hydrogen

The colourless crystalline form of the benzoylpyrazolone (2) has molecules with the NH structure (2c) stabilized by intermolecular hydrogen bonds. At room temperature crystals are monoclinic: P21/c, a 13.508(5), b 9.124(4), c 11.451(3)Ǻ, β 90.80(3)°, Z4; the structure was refined to R 0.059, Rw 0.048. The acetoacetylpyrazolone (3) has the OH structure (3c) with two intramolecular hydrogen bonds. At 193 K crystals are triclinic: Pī , a 7.142(2), b 13.704(8), c 14.699(7)Ǻ, α 117.36(3), β 96.87(3), γ 93.73(3)°, Z 4; the structure was refined to R 0.049, Rw 0.054.

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.

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