Molecules (Sep 2022)

Heterometallic Europium(III)–Lutetium(III) Terephthalates as Bright Luminescent Antenna MOFs

  • Viktor G. Nosov,
  • Arkady S. Kupryakov,
  • Ilya E. Kolesnikov,
  • Aleksandra A. Vidyakina,
  • Ilya I. Tumkin,
  • Stefaniia S. Kolesnik,
  • Mikhail N. Ryazantsev,
  • Nikita A. Bogachev,
  • Mikhail Yu. Skripkin,
  • Andrey S. Mereshchenko

DOI
https://doi.org/10.3390/molecules27185763
Journal volume & issue
Vol. 27, no. 18
p. 5763

Abstract

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A new series of luminescent heterometallic europium(III)–lutetium(III) terephthalate metal–organic frameworks, namely (EuxLu1−x)2bdc3·nH2O, was synthesized using a direct reaction in a water solution. At the Eu3+ concentration of 1–40 at %, the MOFs were formed as a binary mixture of the (EuxLu1−x)2bdc3 and (EuxLu1−x)2bdc3·4H2O crystalline phases, where the Ln2bdc3·4H2O crystalline phase was enriched by europium(III) ions. At an Eu3+ concentration of more than 40 at %, only one crystalline phase was formed: (EuxLu1−x)2bdc3·4H2O. All MOFs containing Eu3+ exhibited sensitization of bright Eu3+-centered luminescence upon the 280 nm excitation into a 1ππ* excited state of the terephthalate ion. The fine structure of the emission spectra of Eu3+ 5D0-7FJ (J = 0–4) significantly depended on the Eu3+ concentration. The luminescence quantum yield of Eu3+ was significantly larger for Eu-Lu terephthalates containing a low concentration of Eu3+ due to the absence of Eu-Eu energy migration and the presence of the Ln2bdc3 crystalline phase with a significantly smaller nonradiative decay rate compared to the Ln2bdc3·4H2O.

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