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 Eu3+ heteroligand complexes containing these complexones was studied. The complexation of Eu3+ with the polymeric complexone and low-molecular-mass organic coligand, thenoyltrifluoroacetone (TTA), ensures efficient energy transfer from molecular orbitals of the polymeric ligand to Eu3+, allowing the Eu3+ luminescence intensity in aqueous solutions to be enhanced by more than 1–1.5 orders of magnitude. The maximal intensity of the Eu3+ luminescence in the heteroligand complex is observed at the [Eu3+]:[COO−] ratio of ∼1 and [Eu3+]/[TTA] = 1.2−1.5. In the presence of univalent metal salts, the Eu3+ luminescence intensity does not noticeably change up to their concentration of 0.4 M. Addition of Ca2+ or Mg2+ salts leads to a drastic decrease in the Eu3+ luminescence intensity in the solution.