Efficient Luminescence Control In Dithienylethene Functionalized Cyclen Macrocyclic Lanthanide Complexes

We report the synthesis of an original ligand scaffold based on a dimethyl-cyclen platform Medo2pa with two dithienylethene units attached to each picolinate arm and the corresponding yttrium(iii), europium(iii) and ytterbium(iii) complexes. All three compounds show reversible photochromism with high photo-conversions. Photoluminescence experiments demonstrate that this design is versatile and adapted for both europium and ytterbium emission switching when measured in frozen organic glasses at 77 K. The OFF/ON luminescence ratio is excellent in the case of europium (4 to 8%) and still quite good in the case of ytterbium (around 13%).