Trivalent Europium Complexes Using Dendritic â-Diketone Ligands

Abstract

A series of photon harvesting lanthanide complexes have been synthesized by chelating dendritic â-diketone ligands to Eu+3. The ligands are modified benzoyltrifluoroacetone units (BTFA) with poly(aryl ether) dendron attachments. These ligands impose a very large asymmetric nature to the first coordination sphere of europium compared to previous dendritic compounds. These complexes exhibit europium emission with no residual emission from the ligands as the dendritic subunits increase from G-0 to G-3. This is due to both antenna and site isolation effects. These complexes mimic light harvesting organisms seen in Nature. When these intensities are compared throughout the series, an increase in intensity is seen where [(G2)BTFA]3Eu is the brightest, with [(G3)BTFA]3Eu being less intense than the G-2 complex. However, the lifetime data indicates that the G-3 complex is the longest lived species.