Photoluminescence of Homoleptic Lanthanide Complexes With Tris(benzotriazol-1-yl)borate

Abstract

Bright photoluminescent neutral complexes having general formula [Ln(tbtz)3] (Ln = Eu, Tb; tbtz = tris(benzotriazol-1-yl)borate) were obtained by reacting K[tbtz] with EuCl3 and TbCl3. The emissions in the visible range, related to the f-f transitions of the trivalent lanthanide ions, are observable upon excitation with wavelengths shorter than 350 nm. The most intense emission bands correspond to the 5D0 → 7F4 transition at 699 nm for the europium complex and to the 5D4 → 7F5 transition at 542 nm for the terbium derivative. The luminescence is in all the cases mostly associated with the antenna-effect from the coordinated tbtz ligands. The synthetic approach was successfully extended to the preparation of the analogous yttrium and gadolinium derivatives. Tricapped trigonal prismatic geometry was attributed to the complexes on the basis of luminescence data and DFT calculations. Highly photoluminescent plastic materials were obtained by embedding small amounts of [Eu(tbtz)3] or [Tb(tbtz)3] in poly(methyl methacrylate).

In situ pyrazolylborate ligand synthesis and coordination behaviours in aluminum oxo clusters

“…Therefore, the in situ ligands play an important role in inducing the aggregation of cluster compounds. Compared with the reported monomers and dimers bridged by classically prepared scorpionates, 14,[25][26][27] we successfully isolated a series of aluminum oxo clusters (AlOCs) via the in situ generation method. These ligands chelate two Al ions at the same time, acting as "edge" ligands and constructing dimeric, tetrahedral and belt-like hexanuclear clusters (Fig.…”

Utility of all-pyrazole heteroscorpionates in f-element chemistry

“…[8][9][10] Tp − , the first example of a scorpionate, is a homoscorpionate: all of the donor sites are equivalent ( pyrazole N); on the other hand, heteroscorpionates are an evolution of scorpionates, defined as anionic, 6e − donor, face-capping ligand where not all three donor sites are identical. 11 Most research efforts involving scorpionates focus on generating different types of homologous scorpionate ligands (and derivative metal-scorpionate complexes) including: trisimidazolylborate, 12 trisbenzotriazolylborate, 13 trismercaptoarylborates and phenyltris(2-pyridyl) borates, 14 and tris(2-pyridyl)amines/phosphines. 15 We recommend the following reviews by Marques and coworkers for f-element scorpionate materials 3,4 and Smith, 2 and Pawar et al, 14 for the versatility of scorpionate ligands in coordination chemistry.…”