Solvent and substituent on the thermal isomerization of substituted azobenzenes. Flash spectroscopic study

Effects of Solvent Viscosity and Polarity on the Isomerization of Azobenzene

“…At the same time, only a little change was detected using a molecule with a simple aminic substitution. 11 An increase of the speed of the reaction in some azobenzene molecules was also reported by Gille 12 and Asano. 13 Bortolus reports an increase in quantum yield of cis-trans photoisomerization in nonpolar environment for azobenzene molecules.…”

The Kinetics of the Cis-to-Trans Thermal Isomerization of 4-Anilino-4’- Nitroazobenzene are Highly Influenced by Solvent Polarity

“…This polar transition state is indicative of a rotational mechanism for the isomerization of 4A4NAB [21,22,24]. This result is expected considering the strong electron withdrawing group (the nitro group) on 4A4NAB and is corroborated by computational studies [22,25,26]. The isomerization mechanism of 4A4NAB can thus be defined as a rotation around the azo bond assisted by a linearization of the angle of the ring attached to the electronwithdrawing substituent.…”

Photo-driven nano-impellers and nanovalves for on-command drug release

“…Early studies 13 have suggested a rotation mechanism of the phenyl ring about the N=N azo double bond, while some of the later works 14,15 proposed an inversion mechanism through a linear transition state. An array of these studies, both experimental and theoretical, each with a different approach and different set of parameters 16,17 , showed that there may not be one general mechanism but rather a competition between the two mechanisms, depending on the local environment 18 , its interaction with other probe molecules 19 and the substituent groups on the molecule 20 .…”