Ukrainian Chemistry Journal, Год журнала: 2024, Номер 90(3), С. 3 - 17

Опубликована: Апрель 29, 2024

The study presents the synthesis, characterization, and photophysical investigation of novel Ln(III)complexes with 1,2,4-triazole-based Salen-type ligands, focusing on europium-centered optical pro­perties. An optimized synthetic method for Ln(III) complex formation was developed use various salts, solvents, deprotonating agents, methanol, triethylamine, triethylorthoformate yielding best results. This approach produced light-yellow crystalline products a 65–70% yield. Structural characterization through IR spectroscopy mass spectrometry confirmed coordination by nitrogen oxygen atoms, as evidenced shifts in vibrational bands indicative Eu–N bonds alterationsin phenolic OH CO stretching modes. UV-Vis absorption spectra revealed bathochromic shifts, indicating changes electron density increased conjugation resulting from formation. Upon excitation, complexes exhibited fluorescence 400–500 nm range phosphorescence 450–550 range, demonstrating effective energy transfer within system. CIE chromaticity coordinates EuL1 (x=0,631, y=0,368) EuL2 (x=0,603, y=0,396) denote deep red emission color purity correlated temperature (CCT) values 2017,94 K 1720,92 K, respectively, their potential high-purity emissions optoelectronic applications. Lifetime measurements (0,544 ms at 298 0,706 77 K) indicate non-radiative relaxation processes that may be modulated local symmetry, suggested distinctive splitting Eu(III) transitions. Emission prominent transitions typical ions, extensive low-symmetry environment, likely C₂ᵥ or Cs point groups. analysis supports number 8, suggesting polyhedral arrangements like bicapped trigonal prism. route effectively produces tunable luminescent properties, revealing key structure-property relationships enabling tailored emissions, making these promising precursors display lighting technologies.

Язык: Английский