Luminescent lanthanide complex with seven-coordination geometry

According to the crystal field theory, the forbidden selection rules in lanthanide’s 4f-4f transition can be relaxed by highly asymmetric structures around the lanthanide ion. Their radiative rates can be increased, facilitating for strong luminescent complex. Geometries of seven-coordination structures are more asymmetric than those of most common eight-coordination ones. In this review, luminescent seven-coordinated lanthanide complexes were introduced. Their photophysical properties are dependent on antenna molecules, ancillary ligands and surrounding media. Photophysical properties and applications using seven-coordinate lanthanide complexes are also presented in this review.