Browsing by Author "Treto Suárez, Manuel A."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Rare-earth-based-metal-organic frameworks with improved visible light harvesting properties: a quantum chemistry study
    (2023) Hidalgo Rosa, Yoan; Saavedra Torres, Mario; Koivisto, Bryan D.; Treto Suárez, Manuel A.; Paez Hernández, Dayan; Zárate, Ximena; Schott Verdugo Eduardo Enrique
    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.
  • Thumbnail Image
    Item
    Tunable optical properties of isoreticular UiO-67 MOFs for photocatalysis: a theoretical study
    (2024) Treto Suárez, Manuel A.; Hidalgo Rosa, Yoan; Saavedra Torres, Mario; Koivisto, Bryan D.; Mena Ulecia, Karel; Páez Hernández, Dayan; Zarate, Ximena; Schott Verdugo, Eduardo
    A theoretical study of the reported photocatalytic systems based on Zr-based MOF (UiO-67) with biphenyl-4,4 '-dicarboxylic acid (bpdc) and 2,2 '-bipyridine-5,5 '-dicarboxylic acid (bpydc) as linkers was performed. Quantum chemical calculations were carried out to understand the optical properties of the materials and to facilitate the rational design of new UiO-67 derivatives with potentially improved features as photocatalysts under ambient conditions. Hence, the effect of the structural modifications on the optical properties was studied considering different designs based on the nature of the linkers: in 1 only the bpdc linker was considered, or the mixture 1 : 1 between bpdc and bpydc linkers (labeled as 1A). Also, substituents R, -NH2, and -SH, were included in the 1A MOF only over the bpdc linker (labeled as 1A-bpdc-R) and on both bpdc and bpydc linkers (labeled as 1A-R). Thus a family of six isoreticular UiO-67 derivatives was theoretically characterized using Density Functional Theory (DFT) calculations on the ground singlet (S0) and first excited states (singlet and triplet) using Time-Dependent Density Functional Theory (TD-DFT), multiconfigurational post-Hartree-Fock method via Complete Active Space Self-Consistent Field (CASSCF). In addition, the use of periodic DFT calculations suggest that the energy transfer (ET) channel between bpdc and bpydc linkers might generate more luminescence quenching of 1A when compare to 1. Besides, the results suggest that the 1A-R (R: -SH and NH2) can be used under ambient conditions; however, the ET exhibited by 1A, cannot take place in the same magnitude in these systems. These ET can favor the photocatalytic reduction of a potential metal ion, that can coordinate with the bpydc ligand, via LMCT transition. Consequently, the MOF might be photocatalytically active against molecules of interest (such as H2, N2, CO2, among others) with photo-reduced metal ions. These theoretical results serve as a useful tool to guide experimental efforts in the design of new photocatalytic MOF-based systems., A theoretical computational protocol was performed to understand the optical properties, the deactivation mechanisms, and the substituent effect for a photocatalytic MOF-based system.