Synthesis of 7-amino-4-trifluoromethyl-2-(1H)-quinolinone and its use as an antenna molecule for luminescent europium polyaminocarboxylates chelates

7-Amino-4-trifluoromethyl-2-(1H)-quinolinone (cs124-CF₃), has been synthesized and found to be an effective antenna molecule (or sensitizer) for europium, but not terbium, luminescence. Specifically, cs124-CF₃ has been covalently attached to the chelates diethylenetriamine-pentaacetic acid (DTPA) and triethylenepentamine-hexanoic acid (TTHA). When bound to europium, excitation in the absorption band (<365nm) of the cs124-CF₃ leads to characteristic europium luminescence: a sharply-spiked emission spectrum, and long-lived emission, including 1.19ms excited-state lifetime for TTHA-CS(CF₃)-Eu³⁺ and 0.62ms for DTPA-cs124-CF₃-Eu³⁺. Emission from DTPA-cs124-CF₃-Eu³⁺ (TTHA-CS(CF₃)-Eu³⁺ ) is about three times (1.7) brighter than that of the non-fluorinated parent compound, 7-amino-4-methyl-2-(1H)-quinolinone (cs124), which we have previously shown to be a valuable lanthanide sensitizer. The excitation of DTPA-cs124-CF₃-Eu³⁺ is red-shifted approximately 15nm, enabling excitation at 355 and 365nm, thereby matching two commonly available excitation sources. The chemical stability of DTPA-cs124-CF₃-Eu³⁺ is also excellent, in contrast to the similar compound, 7-amino-4-trifluoromethyl-2-coumarin. It is expected that cs124-CF₃ will be a valuable sensitizer for europium luminescence in time-resolved fluorescence assays, and will also aide in the design of future sensitizers. It may also be a useful fluorescent dye, independent of lanthanides.