Circularly polarized luminescence and intermolecular energy transfer from terbium(III) to neodymium(III) aminopolycarboxylate complexes

Total luminescence (TL), circularly polarized luminescence (CPL) and luminescence decay measurements have been used to investigate the chiroptical structures and energy transfer processes of mixtures of Tb3+ and Nd3+ complexes in solution with (S,S)-ethylenediamine-N,N-disuccinate (edds) and L-alaninediacetate (alada) ligands. The decay and quenching profiles of the terbium luminescence reveal the energy transfer from Tb3+ to Nd3+ complexes with a quadratic dependence on acceptor concentration. The emission dissymmetry factor g(em), which is in the order of -0.03 near 18 400 cm(-1) in absence of neodymium complexes, is also quenched with increase of the neodymium concentration. In case of edds complexes the quenching of both luminescence and dissymmetry factors is significantly more pronounced than in case of alada complexes. Critical distances of 7.4 nm and 3.7 nm were obtained for edds and alada complexes, respectively.