Curcuminoid ligands for sensitization of near-infrared lanthanide emission.
Fluorescent lanthanide complexes were synthesized using a non-phenolic analog of curcumin as the principal chromophoric chelating ligand. Sensitized, near-infrared fluorescence is observed in these complexes as a result of photo-excitation of the chromophoric ligands, population of the molecular triplet state, and transfer of energy to the emitting lanthanide ion. For the purpose of intra-molecular energy transfer, the triplet states of curcuminoid ligands are more favorably matched with the excited electronic states of neodymium and ytterbium ions than those associated with less conjugated beta-diketonate ligands. Sensitization of fluorescence through an internal redox reaction, thought to occur in other ytterbium complexes, is predicted to be less probable under the present circumstances.
Seltzer
M D
MD
Chemistry and Materials Division, Naval Air Warfare Center, 1900 N. Knox Road Stop 6303, China Lake, California 93555-6106, USA. michael.seltzer@navy.mil
Fallis
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S
Hollins
R A
RA
Prokopuk
N
N
Bui
R N
RN