Showing papers by "Daniel Maspoch published in 2018"
TL;DR: It is shown that truncated rhombic dodecahedral particles of the metal-organic framework (MOF) ZIF-8 can self-assemble into millimetre-sized superstructures with an underlying three-dimensional rhombohedral lattice that behave as photonic crystals.
Abstract: Self-assembly of particles into long-range, three-dimensional, ordered superstructures is crucial for the design of a variety of materials, including plasmonic sensing materials, energy or gas storage systems, catalysts and photonic crystals. Here, we have combined experimental and simulation data to show that truncated rhombic dodecahedral particles of the metal-organic framework (MOF) ZIF-8 can self-assemble into millimetre-sized superstructures with an underlying three-dimensional rhombohedral lattice that behave as photonic crystals. Those superstructures feature a photonic bandgap that can be tuned by controlling the size of the ZIF-8 particles and is also responsive to the adsorption of guest substances in the micropores of the ZIF-8 particles. In addition, superstructures with different lattices can also be assembled by tuning the truncation of ZIF-8 particles, or by using octahedral UiO-66 MOF particles instead. These well-ordered, sub-micrometre-sized superstructures might ultimately facilitate the design of three-dimensional photonic materials for applications in sensing.
244 citations
TL;DR: A novel, ozone-based method for postsynthetic generation of mesoporosity in metal-organic frameworks (MOFs) by selectively breaking the cleavable ligand via ozonolysis to trigger fusion of micropores into mesopores within the MOF framework.
Abstract: Herein we report a novel, ozone-based method for postsynthetic generation of mesoporosity in metal–organic frameworks (MOFs). By carefully selecting mixed-ligand Zr-fcu-MOFs based on organic ligand pairs in which one ligand has ozone-cleavable olefin bonds and the other ligand is ozone-resistant, we were able to selectively break the cleavable ligand via ozonolysis to trigger fusion of micropores into mesopores within the MOF framework. This solid–gas phase method is performed at room-temperature, and, depending on the cleavable ligand used, the resultant ligand-fragments can be removed from the ozonated MOF by either washing or sublimation. Compared to the corresponding highly microporous starting MOFs, the highly mesoporous product MOFs exhibit radically distinct gas sorption properties.
81 citations
TL;DR: A novel one-step method based on the photothermal effect induced by directly irradiating MOFs with a UV-vis lamp enables a very fast solvent removal, thereby significantly reducing the activation time to as low as 30 min and suppressing the need for time-consuming solvent-exchange procedures and vacuum conditions.
Abstract: Metal–organic frameworks (MOFs) usually require meticulous removal of the solvent molecules to unlock their potential porosity. Herein, we report a novel one-step method for activating MOFs based on the photothermal effect induced by directly irradiating them with a UV–vis lamp. The localized light-to-heat conversion produced in the MOF crystals upon irradiation enables a very fast solvent removal, thereby significantly reducing the activation time to as low as 30 min and suppressing the need for time-consuming solvent-exchange procedures and vacuum conditions. This approach is successful for a broad range of MOFs, including HKUST-1, UiO-66–NH2, ZIF-67, CPO-27–M (M = Zn, Ni, and Mg), Fe–MIL-101–NH2, and IRMOF-3, all of which exhibit absorption bands in the light emission range. In addition, we anticipate that this photothermal activation can also be used to activate covalent organic frameworks (COFs).
69 citations
TL;DR: Remarkably, the host-guest studies revealed that 1⋅(BArF)8 is able to discriminate EMFs with the same carbon cage but with different encapsulated cluster and computational studies provide support for these observations.
Abstract: We acknowledge financial support from GenCat (2017 SGR 264 and 2017 SGR 629) and MINECO‐Spain (CTQ2016‐77989‐P and CTQ2017‐87269‐P). L.E. thanks the US National Science Foundation (NSF) for generous support of this work under the NSF‐PREM program (DMR‐1205302) and CHE‐1408865. The Robert A. Welch Foundation is also gratefully acknowledged for an endowed chair to L.E. (Grant AH‐0033). ICN2 acknowledges the support of the Spanish MINECO through the Severo Ochoa Centers of Excellence Program under Grant SEV‐2013‐0295. X.R. and J.M.P. are also grateful to ICREA foundation for ICREA‐Academia awards. We acknowledge Prof. M. Costas for helpful discussions. F.G. acknowledges MINECO for funding through the “Ramon y Cajal” program.
64 citations
TL;DR: This work shows that incorporating crystals of the flexible MOF MIL-88A into a polyvinylidene difluoride (PVDF) matrix affords a polymer composite film that undergoes reversible shape transformations upon exposure to polar solvents and vapours.
Abstract: Herein, we exploit the well-known swelling behaviour of metal-organic frameworks (MOFs) to create a self-folding polymer film. Namely, we show that incorporating crystals of the flexible MOF MIL-88A into a polyvinylidene difluoride (PVDF) matrix affords a polymer composite film that undergoes reversible shape transformations upon exposure to polar solvents and vapours. Since the self-folding properties of this film correlate directly with the swelling properties of the MIL-88A crystals, it selectively bends to certain solvents and its degree of folding can be controlled by controlling the relative humidity. Moreover, it shows a shape-memory effect at relative humidity values from 60 % to 90 %. As proof of concept, we demonstrate that these composite films can lift cargo and can be used to assemble 3D structures from 2D patterns. Our strategy is a straightforward method for designing autonomous soft materials with folding properties that can be tuned by judicious choice of the constituent flexible MOF.
61 citations
TL;DR: The topological influence of zigzag ligands in the assembly of Zr(IV) metal-organic frameworks (MOFs) is described and the value of the transversal parameter in organic ligands for dictating MOF architectures is underscored.
Abstract: Herein we describe the topological influence of zigzag ligands in the assembly of Zr(IV) metal–organic frameworks (MOFs). Through a transversal design strategy using reticular chemistry, we were able to synthesize a family of isoreticular Zr(IV)-based MOFs exhibiting the bcu—rather than the fcu—topology. Our findings underscore the value of the transversal parameter in organic ligands for dictating MOF architectures.
54 citations
TL;DR: In this paper, a continuous-flow spray-drying method was proposed for the simultaneous synthesis and shaping of spherical MOF microbeads in a mixture of water and acetic acid.
51 citations
TL;DR: In this paper, the fabrication of an optical CO2 sensor by integration of a metal-organic framework (MOF) onto bimodal optical waveguides is reported, which is constructed via self-assembly of a transparent film of zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (size: 32 ± 5 nm).
Abstract: The development of devices for sensing and monitoring CO2 levels is crucial for many fields such as food packaging and for human safety indoors. Herein the fabrication of an optical CO2 sensor by integration of a metal–organic framework (MOF) onto bimodal optical waveguides is reported. This sensor is constructed via self-assembly of a transparent film of zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (size: 32 ± 5 nm) on the waveguides. The nanoZIF-8-based sensor exhibits a broad linear response, with limits of detection of 3130 ppm at room temperature and 774 ppm at 278 K. Furthermore, it is robust, selective, fast and reusable, and can be stored under humid conditions with no loss in performance.
51 citations
TL;DR: In this article, a one-pot reaction between Cu(BF4)2·xH2O and 4-mercaptobenzoic acid in acetone or methanol gives rise to the formation of lamellar microcrystals of two Cu(I)-thiophenolate-based coordination polymers.
Abstract: A one-pot reaction between Cu(BF4)2·xH2O and 4-mercaptobenzoic acid in acetone or methanol gives rise to the formation of lamellar microcrystals of two Cu(I)-thiophenolate-based coordination polymers (CPs) with the formulas [CuCT] n (1) (CT = 4-carboxy-thiophenolate) and [CuMCT]n (2) (MCT = 4-methoxycarbonyl-thiophenolate). Both 1 and 2 show a reversible luminescent thermochromic behavior upon cooling, changing their color from pale yellow to green to orange in the case of 1, and from pale orange to green in the case of 2. It is shown that the lamellar character of these crystals, which exhibit micrometer lateral dimensions and sub-micrometer/nanometer thicknesses, allows processing them with an organic polymer such as polyvinylidene difluoride (PVDF) to form thermochromic 1@PVDF and 2@PVDF thin films. These thermal stimuli-responsive thin films are freestanding, free of macroscopic defects, and robust under mechanical bending stress, opening up the possibility to use them in, for example, 2D imaging sensor films.
49 citations
TL;DR: The herein reported results reinforce the potential of this novel immunotherapy to re-establish immunological tolerance, opening the door to new therapeutic approaches in the field of autoimmunity.
Abstract: Type 1 diabetes (T1D) is a metabolic disease caused by the autoimmune destruction of insulin-producing β-cells. With its incidence increasing worldwide, to find a safe approach to permanently cease autoimmunity and allow β-cell recovery has become vital. Relying on the inherent ability of apoptotic cells to induce immunological tolerance, we demonstrated that liposomes mimicking apoptotic β-cells arrested autoimmunity to β-cells and prevented experimental T1D through tolerogenic dendritic cell (DC) generation. These liposomes contained phosphatidylserine (PS)-the main signal of the apoptotic cell membrane-and β-cell autoantigens. To move toward a clinical application, PS-liposomes with optimum size and composition for phagocytosis were loaded with human insulin peptides and tested on DCs from patients with T1D and control age-related subjects. PS accelerated phagocytosis of liposomes with a dynamic typical of apoptotic cell clearance, preserving DCs viability. After PS-liposomes phagocytosis, the expression pattern of molecules involved in efferocytosis, antigen presentation, immunoregulation, and activation in DCs concurred with a tolerogenic functionality, both in patients and control subjects. Furthermore, DCs exposed to PS-liposomes displayed decreased ability to stimulate autologous T cell proliferation. Moreover, transcriptional changes in DCs from patients with T1D after PS-liposomes phagocytosis pointed to an immunoregulatory prolife. Bioinformatics analysis showed 233 differentially expressed genes. Genes involved in antigen presentation were downregulated, whereas genes pertaining to tolerogenic/anti-inflammatory pathways were mostly upregulated. In conclusion, PS-liposomes phagocytosis mimics efferocytosis and leads to phenotypic and functional changes in human DCs, which are accountable for tolerance induction. The herein reported results reinforce the potential of this novel immunotherapy to re-establish immunological tolerance, opening the door to new therapeutic approaches in the field of autoimmunity.
46 citations
TL;DR: Using ozone, the olefin groups of a UiO-66-type MOF are quantitatively transformed into 1,2,4-trioxolane rings, which are then selectively converted into either aldehydes or carboxylic acids.
Abstract: We describe solid-gas phase, single-crystal-to-single-crystal, postsynthetic modifications of a metal-organic framework (MOF). Using ozone, we quantitatively transformed the olefin groups of a UiO-66-type MOF into 1,2,4-trioxolane rings, which we then selectively converted into either aldehydes or carboxylic acids.
TL;DR: In this article, the use of metal acetylacetonate complexes for the large-scale production of metal-organic frameworks (MOFs) is described, and the use is shown to be environmentally sound and high-yielding.
Abstract: Demand continues for environmentally sound, high-yielding processes for the large-scale production of metal–organic frameworks (MOFs) Here we describe the use of metal acetylacetonate complexes as
TL;DR: The covalent post-synthetic modification (CPSM) of MOFs is reported using the photothermal effect to achieve rapid formation of amides from the reaction of representative MOFs with anhydrides under solvent-free conditions.
TL;DR: Two different encapsulation methodologies of bacteriophages are described using two biocompatible materials: a lipid cationic mixture and a combination of alginate with the antacid CaCO3.
Abstract: Encapsulation methodologies allow the protection of bacteriophages for overcoming critical environmental conditions. Moreover, they improve the stability and the controlled delivery of bacteriophages which is of great innovative value in bacteriophage therapy. Here, two different encapsulation methodologies of bacteriophages are described using two biocompatible materials: a lipid cationic mixture and a combination of alginate with the antacid CaCO3. To perform bacteriophage encapsulation, a purified lysate highly concentrated (around 1010-1011 pfu/mL) is necessary, and to dispose of a specific equipment. Both methodologies have been successfully applied for encapsulating Salmonella bacteriophages with different morphologies. Also, the material employed does not modify the antibacterial action of bacteriophages. Moreover, both technologies can also be adapted to any bacteriophage and possibly to any delivery route for bacteriophage therapy.
TL;DR: In this paper, the use of metal-organic framework (MOF) pores decorated with organocatalytic squaramide moieties to confine ring-opening epoxide reactions of diverse substrates is reported.
Abstract: Tandem and multicomponent one-pot reactions are highly attractive because they enable synthesis of target molecules in a single reaction vessel. However, they are difficult to control, as they can lead to the formation of many undesired side-products. Herein we report the use of metal-organic framework (MOF) pores decorated with organocatalytic squaramide moieties to confine ring-opening epoxide reactions of diverse substrates. Controlled mono-addition or tandem reactions inside the pores yield 1,2-aminoalcohols or 1,2,2'-aminodialcohols, respectively, in good yields. In addition, this squaramide-functionalised MOF enables catalysis of higher-complexity multicomponent reactions such as the catalytic ring-opening of two different epoxides by a single amine to afford 1,2,2'-aminodialcohols.
TL;DR: It is shown that this process can be applied to construct ZIF-8-on-ZIF-67 composite particles whose cores are the initially etched particles, and it is demonstrated that introduction of functional inorganic nanoparticles (INPs) onto the crystal surface of etched particles does not disrupt ZIF particle reconstruction.
Abstract: Here, we report the synthesis of (multi)-layered zeolitic imidazolate framework (ZIF-8/-67) composite particles via a sequential deconstruction–reconstruction process. We show that this process can be applied to construct ZIF-8-on-ZIF-67 composite particles whose cores are the initially etched particles. In addition, we demonstrate that introduction of functional inorganic nanoparticles (INPs) onto the crystal surface of etched particles does not disrupt ZIF particle reconstruction, opening new avenues for designing (multi)-layered ZIF-on-INP-on-ZIF composite particles comprising more than one class of inorganic nanoparticles. In these latter composites, the location of the inorganic nanoparticles inside each single metal–organic framework particle as well as of their separation at the nanoscale (20 nm) is controlled. Preliminary results show that (multi)-layered ZIF-on-INP-on-ZIF composite particles comprising a good sequence of inorganic nanoparticles can potentially catalyze cascade reactions.
TL;DR: The results emphasize the environmental susceptibility of metalloporphyrins and how this feature must be taken into account in their design.
Abstract: This work bases on the solid‐state study of a chiral ZnII‐porphyrin derivative (5,10,15,20‐tetra[(4‐R,R,R,R)‐methyl‐2‐phenoxy‐propanoate, 1) building block and its achiral analogous (2). Here, foreseen the rich molecular recognition of the designed metallo‐porphyrins (1 and 2) and tendency to crystallize, we recrystallized both using two sets of solvents (CH2Cl2/CH3OH and CH2Cl2/hexane). As a result, four different crystalline arrangements (1a‐b, 2a‐b, from 0D to 2D) were successfully achieved. We performed solid state studies for all the species, analysing the role played by chirality, solvent mixtures and surfaces (mica and HOPG), on the supramolecular arrangements. As for the combination of solvents and substrates we obtained a variety of micro‐sized species, from vesicles to flower‐shaped arrays, including geometrical microcrystals. Overall, our results emphasize the environmental susceptibility of metallo‐porphyrins and how this feature must be taken into account in their design.