the synthesis, crystal structures and photophysical properties of thirty-one 4f and d-4f polynuclear complexes and coordination polymers based on nine flexible salen-type ligands are described in this review. most of these lanthanide complexes exhibit either interesting “twisted”, drum-like or polymeric structures. in these 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 complexes which have “twisted” and drum-like structures show impressive luminescence properties.
