Related Experiment Video
Updated: Mar 29, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Cooperating Dinitrogen and Phenyl Rotations in trans-Azobenzene Photoisomerization
José A Gámez1, Oliver Weingart2, Axel Koslowski1
1Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.
Abstract:
Semiempirical OM2/MRCI surface-hopping simulations have been performed to study the trans-to-cis photoisomerization of azobenzene upon excitation to the S1 state. The decay dynamics to the ground state shows an oscillatory pattern that can be attributed to an out-of-plane rotation of the N2 moiety. The reaction is thus initially driven by N2 rotation which triggers phenyl rotations around the C-N bonds. The cis isomer is produced most effectively when the phenyl rings rotate in phase. Mode-specific excitations cause variations in the computed decay times and product yields.
Related Concept Videos
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
Thermal and Photochemical Electrocyclic Reactions: Overview
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
NMR Spectroscopy of Benzene Derivatives
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds

