How relevant is anisotropy in bimolecular electron transfer reactions in liquid crystals?

This work aims to describe anisotropy effects on chemical reactions imposed by the structure of liquid crystals. Photo-induced intermolecular electron transfer is studied by means of fluorescence quenching. The charge shift and charge separation reactions are investigated in two different chemical systems. Steady state and time resolved measurements are performed to track the reaction kinetics. In order to extract the electron transfer parameters which are independent of the solvent, the reactions are also conducted in isotropic media at different temperatures and viscosities. A set of diffusion-reaction models with different levels of anisotropy has been developed as well as a numerical method to solve the corresponding partial differential equations. Only the model which introduces anisotropic diffusion and reactivity gives physically meaningful values for all parameters entering the reactivity. It is therefore shown how to adapt diffusion-reaction models able to accommodate any sort of reactivity to complex environments. [Display omitted] •Photo-induced intermolecular electron transfer is studied by means of fluorescence quenching in liquid crystals.•The anisotropy of the nematic phase affects the diffusion assisted reactions.•The electron transfer reactivity is also affected by the anisotropy of the medium.