Intramolecular Hydrogen Bonding in Bilirubin.

Conventional and Unconventional Intramolecular Hydrogen Bonding in some Beta-diketones

This study presents our view of unconventional and conventional intramolecular hydrogen bonds (HBs) for some beta-diketones theoretically and experimentally. According to our results, the groups such as Phenyl and t-But in beta positions increase and CF3 group decrease IHB strength, respectively. For better understanding of the substitution effects, the compounds with similar and different subs...

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...

Normal coordinate analysis of bilirubin vibrational spectra: effects of intramolecular hydrogen bonding

Ah&act-Normal coordinate analyses are presented for half-bilirnbin molecules. Calculations for the A-B pyrromethenone include intramolecular hydrogen bonds, while those for the C-D chromophore exclude intramolecular hydrogen bonds. Valence force-held parameters have been optimized to correlate closely with the IR and Raman spectra of the target molecules. The results of the calculations are com...

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