Impressive near-infrared brightness and singlet oxygen generation from strategic lanthanide–porphyrin double-decker complexes in aqueous solution

Abstract

Although lanthanide double-decker complexes with hetero-macrocyclic ligands as functional luminescent and magnetic materials have promising properties, their inferior water solubility has negated their biomedical applications. Herein, four water-soluble homoleptic lanthanide (<b>Ln</b> <b>=</b> <b>Gd</b>, <b>Er</b>, <b>Yb</b> and <b>La</b>) sandwiches with diethylene-glycol-disubstituted porphyrins (<b>DD</b>) are reported, with their structures proven by both quantum chemical calculations and scanning tunneling microscopy. Our findings demonstrate that the near-infrared emission intensity and singlet oxygen (¹O₂) quantum yields of <b>YbDD</b> and <b>GdDD</b> in aqueous media are higher than those of the reported capped lanthanide monoporphyrinato analogues, <b>YbN</b> and <b>GdN</b>; the brightness and luminescence lifetime in water of <b>YbDD</b> are greater than those of <b>YbN</b>. This work provides a new dimension for the future design and development of molecular theranostics-based water-soluble double-decker lanthanide bisporphyrinates.