Synthesis and photophysical characterization of luminescent lanthanide complexes of nucleotide-functionalized cyclen-and dipicolinate-based ligands

Luminescent Eu(III)-and Tb(III)-complexes based on functionalized tetraazamacrocycle (cyclen) or dipicolinic acid (dpa) metal binding sites, and carrying 20-or 50-linked uridine moieties were prepared. The light-harvesting antennae were either a coumarin (in the cyclen-based architectures) or the dpa-moiety itself. Antenna excitation resulted in metal-centered emission for all complexes. The presence of the uridine resulted in less intense lanthanide emission compared to non-nucleotide-modified reference compounds. Nd(III)-complexes of cyclen ligands carrying a uridine but without a sensitizing antenna were also synthesized; these are envisioned as energy transfer acceptors to the Eu(III)-complexes. The possibility for Eu-to-Nd energy transfer was probed. The reported complexes are models for oligonucleotide- attached lanthanide probes. (C) 2016 The Author(s). Published by Elsevier B.V.