An organic ligand derived from the aminodipicolinic acid is complexed with three different lanthanide ions, Eu(III), Tb(III), Gd(III), to form triple-helical complexes that lead to chiral emitting species. We hypothesize circularly polarized luminescence (CPL) spectroscopy will confirm the chiroptical activity of these complexes later. We will also determine the stability constants for the different forms of the ligand:metal complexes (i.e. 1:1, 2:1 and 3:1); most importantly the stability constant for the 3:1 complex. Direct excitation spectroscopy was used to study the speciation of the Ln(III):ligand complex solution, whereas the efficiency of the energy transfer from the ligand to the metal ions was investigated using steady-state and time-resolved luminescence measurements. An efficient ligand-lanthanide(III) energy transfer was confirmed with these measurements, but a weak metal-centered luminescent quantum yield may be due to an incomplete intersystem-crossing transfer. The stability constants were determined through spectrophotometric titrations.

Lanthanide triple helical complexes with an aminodipicolinic acid derivative

245th National Meeting (2013)

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