Journal article

Self-assembly of highly luminescent lanthanide complexes promoted by pyridine-tetrazolate ligands

Two tridentate pyridine-tetrazolate ligands (H 2pytz and H 2pytzc), analogues of the well-known dipicolinate (H 2dpa) ligand, have been synthesized in a straightforward manner and used for lanthanide(iii) coordination. The structures of the resulting tris-ligand complexes were determined in solution ( 1H-NMR), where they remain undissociated, as well as in the solid state (X-ray diffraction). The solubility of these anionic complexes can be easily tuned by changing the countercation. The bis-tetrazolate-pyridine ligand H 2pytz sensitizes very efficiently both the visible and near-IR emission of the lanthanides, with unusually high luminescence quantum yields in solid state (61% and 65% for Eu and Tb, respectively, and 0.21% for Nd) and in water (63% for Tb and 18% for Eu). Furthermore, the absorption window of the complexes is significantly extended towards the visible region up to 330 nm. The results show that the bis-tetrazolate-pyridine ligand provides a very attractive alternative to the classic dipicolinate ligand. © 2012 The Royal Society of Chemistry.


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