Intramolecular energy transfer processes in rare-earth beta-diketonate complexes investigated by means of transient absorption spectroscopy

• Grant number: 20/16795-6
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: May 01, 2021
• End date: March 11, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Hermi Felinto de Brito
• Grantee: Lucca Blois Guimarães
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 22/13386-3 - Intramolecular energy transfer processes in lanthanide ²-diketone complexes investigated by time-resolved spectroscopy, BE.EP.DD

Abstract

Lanthanide beta-diketonate complexes have been known for a long time in both tris and tetrakis forms. These complexes present characteristic 4f-4f emission of the Ln3+ ion even when the excitation is at the ligand absorption due to the intramolecular energy transfer processes. While the theoretical model for the energy transfer is already well stablished, few experimental techniques are able to observe and track the phenomenon directly. Among these techniques, transient absorption spectroscopy is an interesting candidate since it operates with simple principles while still managing to observe via excited state absorption species that cannot be seen by luminescence techniques. This work main objective is the study of the excited state dynamics in rare earths ²-diketonate complexes with formulae [Ln(L3)(L')n] and Q[Ln(L)4], L stands for the ligands acetylacetone (acac) and thenoyltrifluoroacetone (tta), L': dibenzylsulfoxide (dbso) and phenantroline (phen) and Q: tetrabutylammonium (Bu4N+) and 1-alkyl-3-methylimidazolium (Cnmim+). The compounds will be synthesized and characterized. The excited state dynamics will be investigated by means of electronic spectroscopy in the transient and steady state regime. This work aims to determine the function of the ancillary ligands and counterion in the sensitization process using time resolved techniques. These experiments will be a new approach to study the energy transfer processes, and crucial but still unobserved data can be obtained, such as intersystem crossing rates and lifetime of non-emitting states. This work will be a new contribution to the field of light-converting devices that operates by mean of intramolecular energy transfer. (AU)

Scientific publications

(5)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

ASSUNCAO, ISRAEL P.; BLOIS, LUCCA; CAULI, FLORA P.; FELINTO, MARIA CLAUDIA F. C.; MALTA, OSCAR L.; BRITO, HERMI F.. Luminescence under UV(A, B and C) and sunlight exposure of tetrakis Tb3+carboxylate complexes doped in different polymers. Journal of Alloys and Compounds, v. 1002, p. 11-pg., 2024-07-02. (21/08111-2, 20/16795-6)

ASSUNCAO, ISRAEL P.; COSTA, ISRAEL F.; BLOIS, LUCCA; FELINTO, MARIA CLAUDIA F. C.; DEFLON, VICTOR M.; ANDO, ROMULO A.; MALTA, OSCAR L.; BRITO, HERMI F.. High red luminescence intensity under sunlight exposure of a PMMA polymer doped with a tetrakis Eu³⁺ β-diketonate complex containing a benzimidazolium counterion. RSC ADVANCES, v. 15, n. 1, p. 11-pg., 2025-01-02. (22/12709-3, 21/08111-2, 22/11983-4, 20/16795-6)

BLOIS, LUCCA; NETO, ALBANO N. CARNEIRO; LONGO, RICARDO L.; COSTA, ISRAEL F.; PAOLINI, TIAGO B.; BRITO, HERMI F.; MALTA, OSCAR L.. On the Experimental Determination of 4f-4f Intensity Parameters from the Emission Spectra of Europium (III) Compounds. OPTICS AND SPECTROSCOPY, v. 130, n. 1, p. 8-pg., 2022-01-01. (20/16795-6)

BLOIS, LUCCA; NETO, ALBANO N. CARNEIRO; MALTA, OSCAR L.; BRITO, HERMI F.. The role of the Eu(3+7)F1 level in the direct sensitization of the D-5(0) emitting level through intramolecular energy transfer. Journal of Luminescence, v. 247, p. 7-pg., 2022-07-01. (20/16795-6)

COSTA, ISRAEL F.; BLOIS, LUCCA; PAOLINI, TIAGO B.; ASSUNCA, ISRAEL P.; TEOTONIO, ERCULES E. S.; FELINTO, MARIA CLAUDIA F. C.; MOURA, RENALDO T., JR.; LONGO, RICARDO L.; FAUSTINO, WAGNER M.; CARLOS, LUIS D.; et al. Luminescence properties of lanthanide tetrakis complexes as molecular light emitters. Coordination Chemistry Reviews, v. 502, p. 46-pg., 2023-12-21. (20/16795-6, 22/12709-3, 21/08111-2)