A theoretical spectroscopy investigation of bifunctional platinum-bridged diarylethenes

This Letter is a theoretical investigation of the ground and excited-state properties of diarylethenes coupled through a platinum-containing bridge. Our simulations are performed using (Time-Dependent) Density Functional Theory in conjunction with the Polarisable Continuum Model and aim at characterising the coupling between the two photochromes. It turns out that theory provides results in very good agreement with experiment for the IR, NMR and UV/Vis spectroscopies. The states and orbitals involved in the relevant UV transitions are analysed, allowing to obtain insights regarding the successive electro-cyclisations, the second probably using a triplet pathway.