Abstract
We successfully demonstrate that metal-organic frameworks (MOFs) can be designed to be excited and emit within the biological diagnostic window (650-1450 nm). An isoreticular series of anionic rare earth MOFs with fcu topology was synthesized using 10 different rare earth elements (Y(3+), Eu(3+), Gd(3+), Tb(3+), Dy(3+), Ho(3+), Er(3+), Tm(3+), Yb(3+), Lu(3+)) and common linear ditopic ligands. Five different cationic dye molecules were incorporated into the MOFs via ion exchange. When LDS 750, which exhibits low-energy absorption in the range 450-770 nm, is loaded into an Yb(3+)-MOF, it can be used as an antenna to sensitize the near-infrared (NIR) emission of Yb(3+) centred at 980 nm.