Conventional and Unconventional Intramolecular Hydrogen Bonding in some Beta-diketones

Special issue: intramolecular hydrogen bonding.

Intramolecular hydrogen bonds play critical structure- and function-serving roles in biological and synthetic molecular systems. This special issue, through eight contributions, showcases the prominence of these non-covalent interactions within several scientific disciplines, and in various structural contexts and environments. Reported, for example, are the consequences of intramolecular hydro...

Intramolecular hydrogen bonding in flavin adenine dinucleotide.

Data obtained by means of proton magnetic resonance spectroscopy indicate that specific association of FMN occurs with AMP in aqueous solution, because much weaker interaction is observed with FMN of either GMP or CMP. A comparison of FAD with a 1:1 mixture of FMN and AMP suggests that the flavin is involved in an intramolecular hydrogen bonding with the adenine moiety of FAD. The temperature d...

Energetics and cooperativity in three-center hydrogen bonding interactions. II. Intramolecular hydrogen bonding systems

Some Brief Notes on Theoretical and Experimental Investigations of Intramolecular Hydrogen Bonding.

A review of selected literature data related to intramolecular hydrogen bonding in ortho-hydroxyaryl Schiff bases, ortho-hydroxyaryl ketones, ortho-hydroxyaryl amides, proton sponges and ortho-hydroxyaryl Mannich bases is presented. The paper reports on the application of experimental spectroscopic measurements (IR and NMR) and quantum-mechanical calculations for investigations of the proton tr...

Intramolecular C-H···O hydrogen bonding in 1,4-dihydropyridine derivatives.

The diastereotopy of the methylene protons at positions 2 and 6 in 1,4-dihydropiridine derivatives with various substituents has been investigated. NMR spectroscopy and quantum chemistry calculations show that the CH···O intramolecular hydrogen bond is one of the factors amplifying the chemical shift differences in the 1H-NMR spectra.

Intramolecular hydrogen bonding of azo dyes in aqueous solution.

in 0.1 M ionic strength aqueous solution at 120 for the following: 2,4-dihydroxy4'-nitroazobenzene (I), 2,4-dihydroxy-4'-sulfonateazobenzene (II), and p-(2hydroxy-l-naphthylazo) benzenesulfonic acid (III). The reported values of k231 were 4O X 105, 3.6 X 105, and 3.6 X 106 M-1 sec-1. They attributed the much lower values of k23, for these acids than the value3 k23, 2 X 109 M-1 sec-1 kn,' for th...