How Adsorption Onto TiO2 Modifies the Properties of Multiswitchable DTE Systems: Theoretical Insights

In order to best employ multiphotochromes as complex molecular gates, each isomer should ideally have a distinct optical profile to be selectively addressable. In this ab initio DFT and TD-DFT study, we have modeled the electronic and properties of a series of dithienylethene (DTE) dimers grafted onto an anatase (101) surface. We seek to investigate how grafting onto a TiO2 surface modifies the energy levels and UV-visible spectra the dimers and enhances the asymmetry of the isomers: By extracting information froth the density of states, we have qualified the distinct degrees of interaction between the substrate and each isomeric configuration as CO > CC> OC > OO in order of decreasing electronic coupling: We subsequently use this information to interpret the UV vis spectra computed for the isomers. The results show that the grafted systems present new peaks and shifted S-1 energies compared with the isolated photochrome, suggesting that adsorption onto a TiO2 surface may induce an asymmetric character in the DTE dyad.