An Efficient Design for the Rigid Assembly of Four Bidentate Chromophores in Water‐Stable Highly Luminescent Lanthanide Complexes

A simple bridge solves a difficult architectural problem. Ligand H4tpaen, with an ethylenediamine backbone that has ten donor atoms, yields ten-coordinate lanthanide complexes, thus providing highly effective protection of the metal center from interaction with the solvent molecules. As a result, the EuIII and TbIII complexes of (tpaen)4− show a bright and long-lived luminescence in H2O combined with high solubility and stability.