Synthesis, spectroscopic and computational studies of photochromic azobenzene derivatives with 2-azabicycloalkane scaffold

Abstract

In this study we report the synthesis and photochromic properties of chiral azobenzene derivatives based on the 2-azabicycloalkane skeleton. The photochromic properties of newly synthesized family of azobenzene derivatives have been studied using the UV/Vis spectroscopy. The interpretation of spectral features was supported by the results of the electronic-structure calculations. The experimental data confirm - typical for azobenzene - the occurrence of the trans-cis and the cis-trans photochemical reactions upon irradiation with the visible and UV light, respectively. On the other side, atypical thermal relaxation processes were observed, especially after UV light irradiation, which indicate that thermal back reaction can be not as straightforward as one could expect. The substituents located on the 2-azabicycloalkane lead to some changes in the electronic structure of studied compounds reflected in the changes of the band shapes in the electronic spectra