Water-Soluble Polymeric Heteroligand Europium Complexes

Water-soluble polymeric complexones, N -vinylpyrrolidone- N -allyl- p -aminosalicylic acid copolymers with low content of chelating units, were synthesized. The formation of Eu 3+ heteroligand complexes containing these complexones was studied. The complexation of Eu 3+ with the polymeric complexone and low-molecular-mass organic coligand, thenoyltrifluoroacetone (TTA), ensures efficient energy transfer from molecular orbitals of the polymeric ligand to Eu 3+ , allowing the Eu 3+ luminescence intensity in aqueous solutions to be enhanced by more than 1–1.5 orders of magnitude. The maximal intensity of the Eu 3+ luminescence in the heteroligand complex is observed at the [Eu 3+ ]:[COO − ] ratio of ∼1 and [Eu 3+ ]/[TTA] = 1.2−1.5. In the presence of univalent metal salts, the Eu 3+ luminescence intensity does not noticeably change up to their concentration of 0.4 M. Addition of Ca 2+ or Mg 2+ salts leads to a drastic decrease in the Eu 3+ luminescence intensity in the solution.