Browsing by Author "Lancheros Sánchez, Andrés Fernando"

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    New Pillar-MOF with Nitrogen-Donor Sites for CO2 Adsorption
    (2024) Lancheros Sánchez, Andrés Fernando; Goswami, Subhadip; Zarate, Ximena; Blanco, Elodie; Schott Verdugo, Eduardo Enrique; Hupp, Joseph T.
    A new pillar-MOF [Zn2(L)(DABCO)] was solvo-thermally synthesized by using a new linker (L = 4,4′-(1,4-phenylenebis(3,5-dimethyl-1H-pyrazole-4,1-diyl))dibenzoic acid),Zn(NO3)2·6H2O, and triethylenediamine (DABCO) as pillarlinker. It was characterized using single-crystal X-ray diffraction,powder X-ray diffraction (PXRD), thermogravimetric analysis(TGA), and scanning electron microscopy (SEM) and tested forCO2 adsorption. It exhibits dinuclear paddle−wheel nodes wherethe Zn(II) cations are coordinated by four equatorial L linkersgenerating two-dimensional sheets. DABCO acted as a pillarbinding the sheets to obtain a neutral three-dimensional frameworkthat shows one-dimensional square channels. The new pillar-layered MOF presents micro- and mesopores, and its crystallinity is preserved after activation at 160 °C × 16 h and adsorption ofCO2. Due to the presence of the pyrazole nitrogen atoms in the framework, which have an increased affinity toward CO2, this newmaterial exhibited a reasonable CO2 uptake capacity and a low isosteric enthalpy of adsorption (Hads)
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    Nitrogen-enriched flexible metal-organic framework for CO2 adsorption
    (2024) Lancheros Sánchez, Andrés Fernando; Goswami, Subhadip; Zarate, Ximena; Schott Verdugo, Eduardo Enrique; Hupp, Joseph T.
    A novel MOF named [Zn-2(L)(DMF)] was synthesized using solvothermal methods from the reaction of the new linker (4,4 ',4 ''-(4,4 ',4 ''-(benzene-1,3,5-triyltris(methylene))tris(3,5-dimethyl-1H-pyrazole-4,1-diyl))tribenzoic acid) and Zn(NO3)(2)6H(2)O. This new MOF was characterized by means of different techniques: powder X-ray diffraction, N-2 adsorption and desorption isotherms, thermogravimetric analysis, and scanning electron microscopy. Furthermore, suitable crystals were obtained, which allowed us to perform the X-Ray structure determination of this MOF. The capability of these new MOF to adsorb CO2 at different temperatures was measured and its isosteric enthalpy of adsorption was calculated. The novel MOF shows an uncommon node composed of a Zn-3(-COO)(6)(DMF)(2), and the asymmetric unit contains one crystallographically independent linker, one DMF molecule, and two Zn atoms. The [Zn-2(L)(DMF)] MOF is a microporous material with high crystallinity and stability up to 250 degrees C. The multiple nitrogenated pyrazole linkers in its framework enhance its CO2 adsorption capabilities. This material exhibits a low CO2 isosteric enthalpy of adsorption (H-ads), comparable to previously reported values for similar nitrogenated materials. All the observed CO2 adsorption capacities were further supported by DFT calculations.
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    Novel pillar-layered metal organic frameworks based on pyrazole-carboxylate linkers for CO2 adsorption
    (2023) Lancheros Sánchez, Andrés Fernando; Schott Verdugo, Eduardo; Pontificia Universidad Católica de Chile. Facultad de Química y Farmacia
    With an increasing global population and energy requirement, the concentration of greenhouse gases, especially CO2, grows rapidly in the atmosphere. One of the solutions to mitigate this problem is to develop materials that can effectively capture and store CO2. The conventional method relies on using amine solvents to bind to CO2 chemically, but it is still not widely accepted because of the price of its regeneration. Porous solid materials such as Metal-Organic Frameworks (MOFs) have been suggested as CO2 adsorbents due to their-well defined molecular scale porosity, crystallinity, synthetic tunability, and high CO2 uptake capacity and selectivity. This Chemistry Ph.D. project first synthesized and characterized three novel carboxylate-pyrazole linkers (Ap, Bp, and Cp). Those linkers allowed the synthesis of novel MOFs using Zn(II)/Cu(II) metal nodes and 4,4’-bipyridine/DABCO pillaring linkers. Five MOFs were obtained, three from the Ap linker, one from Bp, and one from Cp. The carboxylate groups and pyridyl nitrogens are engaged in coordination bond formation with the metal node that propagates in generating 3D porous structures, and the pyrazole nitrogens remain free to interact with CO2. All the materials have shown excellent structural stability and crystallinity. The CO2 uptake was between 3.4-7.20% wt% at 273 K and 75 kPa. For Ap MOFs, changing the metal node from Zn(II) to Cu (II) and replacing the pillaring linker from 4,4’-bipyridine to DABCO makes it possible to increase CO2 adsorption. The isosteric enthalpy of adsorption (Hads) of CO2 adsorption for all of them was between 23-40 kJ/mol, making it more cost-effective for the MOF’s regeneration after CO2 storage. All five MOFs are good candidates for CO2 adsorption because of their stability, capture capabilities, and energy required for CO2 adsorption and regeneration.