Design and synthesis of europium luminescent bio-probes featuring sulfobetaine moieties

Herein we report the straightforward preparation of chromophore-functionalized TACN ligand via Cu-free cross-coupling reactions using a common halogenated platform. This versatile methodology allows the preparation of original macrocyclic ligand featuring both optimized antenna for the sensitization of europium luminescence and sulfobetaine zwitterionic groups to ensure water solubility of the complex. In addition preliminary two-photon excited microscopy imaging experiments of fixed cells reveal that sulfobetaine groups are able to limit undesirable non specific interactions with biological surrounding.