The influence of cation-π interactions on the strength and nature of intramolecular O...H hydrogen bond has been investigated by quantum chemical calculations in orthohydroxy benzaldehyde (HBA) compound. Ab initio calculations have been performed at MP2/6-311++G** level of theory. Vibrational frequencies and physical properties such as chemical potential and chemical hardness of these compounds...

The presence of an intramolecular hydrogen bond has been proposed to play a key role in the catalysis of amide isomerization by peptidylprolyl isomerases (PPIases), which are highly conserved and ubiquitous rotamase enzymes that catalyze the cis-trans isomerization of proline residues in peptides and proteins. We present herein kinetic and spectroscopic evidence that indicates the existence of ...

In the mol-ecule of the title compound, C(12)H(16)N(2)O(4), an intra-molecular N-H⋯O hydrogen bond results in the formation of a six-membered ring having an envelope conformation. In the crystal structure, a bifurcated intra/intermolecular N-H⋯(O,O) hydrogen bond generates inversion dimers.

In this study, we synthesized two novel carboxylic acid and carboxylate compounds, both of which had an amide group linked with an azomethine moiety to introduce photoinduced switching of the intramolecular NH...O hydrogen bond. We suggest that the cis-carboxylate compound forms a stronger intramolecular NH...O hydrogen bond than the cis-carboxylic acid compound.

The non-symmetric title mol-ecule, C32H34N2O5, is based on a tetra-substituted ethyl-enedi-amine backbone. The mol-ecular structure consists of three hy-droxy-benzyl groups and one 2-hy-droxy-5-methyl-benzaldehyde group bonded to the N atoms of the di-amine unit. The ethyl-enedi-amine skeleton shows a regular extended conformation, while the spatial orientation of the phenol arms is governed by...

Three N-substituted 5-chlorosalicylamides (4-chlorophenyl, 2a; benzyl, 2b; phenethyl 2c) differing in the length of the 'linker' between the benzene ring and the amide moiety were prepared in order to compare their supramolecular architecture. The intramolecular NH··O(H) hydrogen bond and the intermolecular C=O··H–O hydrogen bond were found in the crystal structure of 2a and 2c thus forming an ...

The conformational isomerism and stereoelectronic interactions present in 2'-haloflavonols were computationally analyzed. On the basis of the quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analysis, the conformer stabilities of 2'-haloflavonols were found to be dictated mainly by a C=O···H-O intramolecular hydrogen bond, but an unusual C-F···H-O hydrogen-bond and in...

2D 1H-15N HMBC NMR acquired at natural abundance and DMSO titration monitored by 1D 1H NMR verified the existence of an intramolecular hydrogen bond that was designed to mimic the pyrimidinone ring of a class of kinase inhibitors. A scalar coupling across the hydrogen bond was detected in organic and aqueous solvent, suggesting a simple and general approach for testing the propensity of intramo...

An analysis of hydrogen bonds involving ester Osp3 atoms as acceptors has been performed based on the data extracted from the Cambridge Structural Database [Allen (2002). Acta Cryst. B58, 380-388; version 5.25, November 2003], using the ConQuest package to evaluate the stereochemical and electronic properties of the acceptors. Evidence for the existence of this particular type of hydrogen bond ...

The title compound, C24H22N4O5, crystallizes with two mol-ecules in the asymmetric unit (Z' = 2) oriented almost perpendicular to each other [dihedral angle between the central core of each mol-ecule = 77.95 (3)°]. The two mol-ecules exhibit similar conformations with an extended structure. An intra-molecular C-H⋯N hydrogen bond occurs in each mol-ecule. The two mol-ecules are linked by a bifur...