Luminescence properties of lanthanide tetrakis complexes as molecular light emitters

Research on luminescent tetrakis coordination compounds containing trivalent lanthanide ions (Ln3+) has greatly increased in the last two decades owing to their unique spectroscopic properties and advantages over traditional tris compounds. In this review, we target the synthesis, crystal structure, and luminescence properties of Ln3+ tetrakis coordination compounds Q[Ln(L)4] as molecular light emitters with various classes of ligands (L: β-diketonates, carbacylamidophosphonates, sulfonylamidophosphonates, alkyldithiocarbamate and carboxylates) and different counterions (Q+). Moreover, we describe their special photophysical features and the potential of lanthanide tetrakis complexes in molecular design to obtain efficient luminescent materials. It is also discussed the relationship between structural data and experimental-theoretical approaches for the modeling of luminescence properties of this class of compounds. Additionally, we highlight some potential applications of Ln3+ tetrakis coordination compounds as efficient luminescent materials.