Département de chimie moléculaire

The design and synthesis of dinuclear-lanthanide complexes possessing triazole-based bridges, formed by using Cu catalyzed 1,3-cycloaddn. reactions between heptadentate alkyne functionalized cyclen Eu or Tb complexes and di-azides (CuAAC reactions), are described. While this click reaction worked well for the formation of the homo-Eu(III) and Tb(III) bis-tri-arm cyclen N,N-dimethylacetamide complexes, 2Eu and 2Tb, and for the homo-Eu(III) chiral N-methylnaphthalene based complexes 3Eu (S,S,S) and 4Eu (R,R,R), the formation of the Eu(III) complex of the primary amide analog of 2, 1Eu, was not successful, clearly demonstrating the effect that the nature of the pendant arms has on this reaction. Also, the click reactions between the free alkyne cyclen bis-derivs. (5-8) and the di-azide were unsuccessful, most likely due to the high affinity of the cyclen macrocycles for Cu(II). The Eu(III) complexes of 2-4 and 2Tb all gave rise to sensitized metal ion centered emission upon excitation of the triazole or the naphthalene antennae in MeOH soln., and their hydration states were detd., which showed that while the Eu(III) mono-nuclear complexes had q ∼ 2, the click products all had q ∼ 1. In the case of 3Eu (S,S,S) and 4Eu (R,R,R), the circular polarized emission (CPL) was also obsd. for both, demonstrating the chiral environment of the lanthanide centers. [on SciFinder(R)]