Examinando por Autor "Hidalgo-Rosa, Yoan"

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    Ítem
    Rare-earth-based metal–organic frameworks with improved visible-light-harvesting properties: a quantum chemistry study
    (Springer, 2023-05-25) Hidalgo-Rosa, Yoan
    This report proves that improving the visible-light-harvesting properties in rare-earth-based metal–organic frameworks (RE-MOFs) (labelled as RE–UiO-66, UiO = University of Oslo MOFs), with the aim of performing as potential visible-light-driven photocatalysts, is achievable. Thus, the design of MOFs with specific applications, especially those involving sunlight and material interactions, represents a growing field, which has been addressed in the herein work using quantum mechanical tools. We achieved to relate the light absorption properties with the structure in systems Y–UiO-66, Sc–UiO-66 and La–UiO-66, by evaluating the inclusion of well-known electron donor substituents in the structure of the 1,4-benzenedicarboxylate (BDC) linker (i.e. BDC-R, R: –CH3, –OH, –SH and –NH2). The electronic structure and optical properties of Y–UiO-66 were rigorously investigated using computational techniques combining molecular and periodic density functional theory (DFT) calculations. As a remarkable result, it was shown that including the groups –SH or –NH2 in the BDC linker, induced a shift in the absorption bands to the visible region (≥ 400 nm). Hence, a group of new RE-MOFs materials with optimal structural and photocatalytic properties is proposed. This could encourage researchers to prepare these new materials to be tested in photocatalysis, such as cleaving the C–H bond, water splitting or photocatalytic degradation of organic contaminants.
  • Miniatura
    Ítem
    Tuning the sensitization pathway T1→ 5DJ in Eu-based MOF through modification of the antenna ligand: a theoretical approach via multiconfigurational quantum calculations
    (Elsevier, 2023-04-27) Hidalgo-Rosa, Yoan
    The current study demonstrates the possibility of improving the efficiency of Eu3+ sensitization in an Eu-based MOF, labelled as EuL-R, by modifying the antenna ligand. The electronic structure of seven antenna ligand derivatives with the form R-4-(pyrimidin-5-yl) benzoic acid (L-R) ligand derivates was thoroughly examined in this research. Also, the most likely energy transfer channels for the sensitization pathway of Eu3+ ions in the EuL-R systems (R: CH3, –OH, –SH and –NH2) was studied. The efficiency in the intersystem crossing (ISC) process from S1 to T1 in the antenna make plausible a subsequent energy transfer to the emissive state in the Eu3+. This process was studied via multireference CASSCF/NEVPT2 calculations due to the multiconfigurational character of Eu3+ ions. Based on Latva and Reindhout's empirical rules, the 4-(2-(thiophen-2-yl)pyrimidin-5-yl)benzoic acid (L6) was chosen as efficient antenna for the sensitization process in this system. In conclusion, it was discovered that including the thiophenyl group at the L antenna (L6), increased the energy gaps S1→T1 and T1→5DJ (Eu3+) to an optimal range for the ISC and subsequent energy transfer. Finally, a deeply understanding of the sensitization and emission mechanisms was possible from the excited-state dynamics analysis of the L6 antenna, via fluorescence, inter-system crossing (ISC), phosphorescence, and kF, kISC, and kP, rates calculations. This study therefore highlights the importance of a thorough theoretical procedure via a robust quantum mechanical tool to guide the development of novel luminescent lanthanide-based MOFs.