On the geometries and UV/Vis spectra of substituted trans-azobenzenes

Using wavefunction and density-based ab initio approaches, we have evaluated the structural parameters and the electronic absorption spectra of three para disubstituted trans azobenzene derivatives: 4,4′-Cl, 4,4′-NO2, and 4,4′-NMe2. These calculations were performed in both gas-phase and ethanol, and large basis set effects have been unravelled at the second-order Møller–Plesset level. All three derivatives are found to present a planar azobenzene core.