文摘
The synthesis, crystal structures, and photophysical properties of twenty-three 4f and d-4f clusters based on eight salen-type Schiff base ligands are described in this chapter. Most of these lanthanide-based clusters exhibit interesting “enclosed” structures, such as multi-decker, “twisted,” and drum-like structures. In these polynuclear complexes, the multidentate salen-type ligands can efficiently sensitize lanthanide emissions by serving as antennas that absorb excitation light and transfer the energy to the lanthanide centers. With the lanthanide ions encapsulated by chromophoric salen-type ligands and shielded from solvent molecules which can quench the emissions from lanthanide ions, those lanthanide-based clusters with “enclosed” structures show impressive luminescence properties.