Related Experiment Video
Updated: May 7, 2026

Evaluation of Oxidative Stress in Biological Samples Using the Thiobarbituric Acid Reactive Substances Assay
Published on: May 12, 2020
Photoinduced tautomerism of 2-thiobarbituric Acid studied by theoretical and experimental methods
Abstract:
Combined, theoretical and experimental, investigation was performed to study the mechanism of the photoinduced tautomerism of 2-thiobarbituric acid (TBA). The irradiation of the solution of TBA in polar aprotic solvent with UV light (maximum at 366 nm) showed oxo-hydroxy photoisomerization of the triketo form of TBA to the hydroxy-imino tautomer. The studied mechanisms (TD DFT) of the photoinduced NH and OH dissociations in the keto and enol tautomer revealed that the proton detachment in the triketo tautomer occurs in the bright 1nSσ* excited state. In the hydroxy-imino tautomer this mechanism is driven by the repulsive 1πσ* excited state. The excited-state relaxation mechanisms occur by low-lying So-S1 conical intersections.
More Related Videos
09:54Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes
Published on: September 12, 2018
07:49Characterizing Lewis Pairs Using Titration Coupled with In Situ Infrared Spectroscopy
Published on: February 20, 2020
Related Concept Videos
Keto–Enol Tautomerism: Mechanism
Classification of Titrimetric Analysis Based on Reaction Types
Titrations between an acid and a base lead to neutralization reactions that form...
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
IR and UV–Vis Spectroscopy of Carboxylic Acids
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency, 1710 cm−1. The C=O bond of the...
Reactions of Aldehydes and Ketones: Baeyer–Villiger Oxidation
The carbonyl center is activated by...