Wydział Chemii

Konstantin P. Zhuravlev

Łukasz Michnik

Paula Gawryszewska

Vera I. Tsaryuk

Valentina A. Kudryashova

2019

Inorganica Chimica Acta

492

1-7

10.1016/j.ica.2019.04.014

Naukowa

Angielski

Artykuł

Lanthanide pyrrole-2-carboxylates [{Ln(L)₃(H₂O)₂}·H₂O]_n (Ln = Eu, Gd, Tb) were synthesized and investigated using single crystal X-ray diffraction and optical spectroscopy (luminescence, luminescence excitation and vibrational IR spectra). The europium pyrrole-2-carboxylate crystallizes as a 2D network structure in the P2₁/c space group. The Eu³⁺ coordination polyhedron formed by five carboxylic groups and two water molecules can be described as a distorted single-capped square antiprism. The luminescence spectra indicate a low symmetry of the charge distribution around the Ln³⁺ ion that corresponds to the C₁ symmetry of the coordination environment of Eu³⁺ ion in the [{Eu(L)₃(H₂O)₂}·H₂O]_n crystal lattice. The low-energy ligand–metal charge transfer (LMCT) state was identified in the europium compound. The shortening of the ⁵D₀ (Eu³⁺) lifetime in the 230–295 K temperature region, when the compound is heated from 77 to 295 K, and the low luminescence intensity of the europium pyrrole-2-carboxylate are caused by the participation of the LMCT state in quenching processes. The energy of activation determined for the ⁵D₀ – LMCT crossover is 3900 ± 100 cm⁻¹.

Eu3+, Tb3+, Pyrrole-2-carboxylate, Luminescence, LMCT, X-ray crystal structure

http://dx.doi.org/10.1016/j.ica.2019.04.014

http://www.elsevier.com