Related Experiment Video
Updated: Jun 19, 2026

Facile Preparation of 4-Substituted Quinazoline Derivatives
Published on: February 15, 2016
Experimental and quantum chemical study of photochemical properties of 4-hydroxyquinoline
Peter S Sherin1, Nina P Gritsan, Yuri P Tsentalovich
1International Tomography Center SB RAS, Institutskaya 3a, 630090, Novosibirsk, Russia.
Abstract:
UV irradiation of aqueous 4-hydroxyquinoline (4HQN) solutions results in the formation of the triplet states with the quantum yields 30%, 35%, and 7.5% in acidic, neutral, and basic solutions, respectively. In neutral solutions, the keto form is the major tautomeric structure for ground, excited singlet and triplet states of 4HQN. Triplet 4HQN reacts with amino acids tryptophan and tyrosine and with antioxidant ascorbate via the mechanism of electron transfer. The individual experimental and calculated UV-Vis spectra of different acid-base forms of 4HQN in the ground and triplet excited states, as well as reduced and oxidized forms of 4HQN, are reported. Under intense laser irradiation 4HQN undergoes biphotonic ionization, the excited singlet state being the precursor for photoionization.
Related Concept Videos
Oxidation of Phenols to Quinones
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Thermal and Photochemical Electrocyclic Reactions: Overview
Variables Affecting Phosphorescence and Fluorescence
Radical Chain-Growth Polymerization: Overview

![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)