Synthesis and photoinduced switching properties of C₇-heteroatom containing push–pull norbornadiene derivatives

We report the synthesis and characterization of heteroatom-incorporated norbornadiene (NBD) derivatives. Push-pull substitution on the 2 and 3 position as well as introduction of oxygen or nitrogen at position 7 of the NBD scaffold have led to the development of a new family of photoswitches. We studied the potential conversion of norbornadiene to quadricyclane (QC) isomers. As main investigation tools, UV-vis and NMR spectroscopy were utilized. We determined significant spectral features of the formed NBD species, including λ_max and λ_onset values, all of which exhibit redshifts compared to their isocyclic counterparts. Additionally, the selected QC isomers were subjected to thermal and catalytic back-conversion studies.