Spurgeon Smith
Tanzania
Research Article
The Kinetics of the Cis-to-Trans Thermal Isomerization of 4-Anilino-4’-Nitroazobenzene are Highly Influenced by Solvent Polarity
Author(s): Spurgeon Smith and Fadi Bou-AbdallahSpurgeon Smith and Fadi Bou-Abdallah
The thermally stable trans isomers of donor-acceptor substituted azobenzene dyes can be easily transformed into unstable cis-form by light. Although azobenzene and its derivatives have been extensively investigated over the years, many aspects of the isomerization reaction kinetics are still unclear or controversial at best. Here, we investigate the kinetics of the thermal cis-trans isomerization of 4-anilino-4'-nitroazobenzene (4A4NAB) in six solvents of different polarities by means of flash photolysis. Using the transition state theory, we were able to determine a number of thermodynamic quantities including the standard enthalpy of activation Δ‡H0, the standard entropy of activation Δ‡S0, the Gibbs free energy of activation Δ‡G0, and the quasi-equilibrium constant K‡ of the isomerization reaction. Higher rates of isomerization and .. View More»
