News



Feb-2024
Just accepted article in ChemCatChem:
Titanium MXenes as Heterogeneous Catalysts for the Styrene-to-Benzaldehyde Oxidation: Influence of the Etching Conditions

Ti3C2Tz MXenes are prepared under different etching conditions and tested as heterogeneous catalysts for the selective oxidation of styrene to benzaldehyde. A clear dependence is observed between the etching conditions (hydrofluoric acid concentration and etching time) and the surface chemistry, morphology and catalytic performance of the resulting MXenes. Under appropriate conditions, etching of the Ti3AlC2 MAX phase precursor with concentrated HF produces Ti3C2Tz MXenes with highly accessible accordion-like structures and accessible Ti-O surface terminations that can act as active species for the catalytic process, keeping up with the best catalysts reported so far for this reaction. The present study represents one of the few existing reports on catalytic properties of MXenes under mild liquid-phase conditions, paving the way for future developments of this new family of 2D materials for fine chemical applications.


Dec-2023
Book Chapter just published:
Acid-catalyzed diastereoselective reactions inside MOF pores, in Catalysis in confined frameworks: Synthesis, characterization and applications, A Wiley-VCH book edited by H. García and A. Dhakshinamoorthy
ISBN 978-3-527-83956-1






In this chapter we discuss the use of achiral metal-organic frameworks (MOFs) as porous
heterogeneous catalysts for diastereoselective transformations. The list of selected examples includes Meerwein–Ponndorf–Verley reduction of carbonyl compounds, aldol addition, Diels–Alder, isomerization and cyclopropanation reactions. In general, a prochiral functional group of the reaction is selectively transformed into one pair of diastereomers through the imposition confinement effects driven by the MOF porosity. The last section of this chapter summarizes the state-of-the-art of this field and we provide our views for development of novel MOF-engineered materials for (diastereo)selective reactions.














March-10-23
Just accepted article in ACS Applied Energy Materials:
AgBTC MOF-mediated approach to synthesize Silver nanoparticles decorated on reduced graphene oxide (rGO@Ag) for energy storage applications


Nanowires of Silver based metal organic framework (MOF) (AgBTC, BTC = 1,3,5-benzenetricxarboxylate) were grown onto graphene oxide layers to generate GO-AgBTC nanocomposites. Thermal treatment of these composites in inert atmosphere produced reduced graphene oxide (rGO) decorated with well-dispersed and homogeneous silver nanoparticles (rGO@Ag). The easy and scalable synthesis of AgNPs via MOF-mediated synthesis was achieved by the thermal decomposition of the AgBTC directly onto rGO surface. The structure, morphology and electrochemical properties of this novel material were investigated by XRD, Raman, TGA, FE-SEM, TEM, Cyclic Voltammetry and galvanostatic charge and discharge experimental techniques. The results showed improved capacitive features for rGO@Ag. Specific gravimetric capacitance measured by galvanostatic charge-discharge yielded a value of 151.97 F/g at the current density of 0.5 A/g, pointing out that MOF-mediated synthesis offers a facile method to generate rGO electrodes decorated by uniformly distributed nanoparticles for energy storage devices.




Feb-16-2023 Just accepted article in Materials Chemistry Frontiers:
Sulfide Organic Polymers as novel and efficient metal-free heterogeneous Lewis acid catalysts for esterification reactions

Herein, we report on the synthesis of four organosulfide-based covalent organic polymers prepared via click processes, consisting of either SN2 (SOP-1 and SOP-3) or thiol-yne (SOP-2 and SOP-4) coupling reactions. Formation of the SOPs in high yields is confirmed by solid-state 13C NMR and FTIR spectroscopies, while the sulfur contents of SOP-type materials confirm the expected C:S molar ratio for the formation of stoichiometric products. CO2 adsorption isotherms reveal the porosity of SOPs, with specific surface areas up to 180 m2g-1 and strongly dependent on the ligands used. The catalytic activity of SOPs is evaluated for carboxylic acid esterification reactions, obtaining high conversions and efficient recyclability. The proposed reaction mechanism consists in the activation of the carboxylic acid by hypervalent S···O (nOsS*) interactions with sulfur centres of the SOPs, which increase the electrophilic character of the carboxylic carbon and facilitate the addition of the alcohol. Thus, SOPs constitute a novel class of metal-free heterogeneous Lewis acid (organo)catalysts.




Feb-7-2023 Just accepted article in Molecular Systems Design & Engineering:
Zr-containing UiO-66 Metal Organic Frameworks as efficient heterogeneous catalysts for glycerol valorization: Synthesis of Hyacinth and other glyceryl acetal fragrances, (doi: 10.1039/D2ME00255H)

Zr-containing UiO-66 and UiO-66-NH2 are good heterogeneous catalysts for the acetalization of phenylacetaldehyde with glycerol, producing the corresponding hyacinth fragrance in high yields after short (2h) reaction times. Mixtures of 1,3-dioxolanes and 1,3-dioxanes are obtained, whose ratio can be modified between 2.8 and 4.6 depending on the catalyst used, the amount of missing linker defects of the solid, and the reaction time. The catalysts are stable under the reaction conditions used, and they can be reused without loss of activity or selectivity. The scope of UiO-66 materials is demonstrated for the formation of other glyceryl acetals of interest for the flavoring industry, which represent an interesting route for glycerol valorization.




Sept-21-2022
Just published article in Molecules:
MOF-808 as a highly active catalyst for the diastereoselective reduction of substituted cyclohexanonesMolecules, 27 (2022) 6315.



Zr-containing MOF-808 is an excellent heterogeneous catalyst for the diastereoselective Meerwein-Ponndorf-Verley reduction of substituted cyclohexanones. The presence of substituents at 2- or 3 position of the cyclohexanone ring strongly drives the reaction towards the formation of one of the two possible isomers. For 3-methyl cyclohexanone, the available space inside the MOF pores allows the formation of the bulkier transition state leading to the thermodynamically stable 3-cis-cyclohexanol. For 2-methyl cyclohexanone, the reaction rate is much slower and the final diastereoselectivity depends on the size of the alcohol used. Finally, reduction of 2-phenyl cyclohexanone is considerable faster over MOF-808 than for any other catalyst reported so far. The large size of the phenyl favors the selective formation (up to 94% selectivity) of the cis-alcohol, which goes through a less hindered transition state.


 


Dec-25-2021Just accepted article in Advanced Sustainable Systems:
Zr-containing UiO-66 Metal-Organic Frameworks as highly selective heterogeneous acid catalysts for the direct ketalization of levulinic acidAdv. Sust. Syst., (2022) 2100451.

Zr-containing UiO-66 materials are active and reusable heterogeneous catalysts for the selective ketalization of levulinic acid (LA) with 1,2-propanediol, affording selectivities of up to 91-93% at full LA conversion, with very low levels of ester or ketal-ester byproducts. This allows preparing the target ketal directly from LA and avoiding intermediate esterification steps of LA to levulinate esters to minimize the formation of unwanted side-products. The catalytic activity of UiO-66 is found to depend critically on the hydration degree of the solid and the amount of missing linker defects. The most likely active sites for ketalization in (defective) UiO-66 are Brønsted-induced acid sites arising from the strongly coordination and polarization of H2O molecules onto accessible Zr4+ associated to missing linker defects. A progressive deactivation is observed upon catalytic reuse, which is attributed to adsorbed reaction products poisoning the catalytic sites. These adsorbed products are easily removed by washing the spent catalyst with a dilute 2% HCl ethanolic solution, which completely restores the initial catalytic activity while maintaining the crystallinity of the solid intact.

Sept-21-2021Just accepted article in Molecular Catalysis:
Conversion of Levulinic acid to γ-valerolactone over Zr-containing Metal-Organic Frameworks. Evidencing the role of Lewis and Brønsted acid sites, Mol. Catal. 515 (2021) 111925 (doi. 10.1016/j.mcat.2021.111925)
Zr-containing UiO-66 and MOF-808 are evaluated for converting levulinic acid (LA) into g-valerolactone (GVL) through various routes: i) Step-wise esterification of LA to n-butyl levulinate (nBuL) and Meerwein-Ponndorf-Verley (MPV) reduction to GVL; ii) One-pot two-steps esterification with n-butanol followed by MPV reduction with sec-butanol; and iii) direct conversion of LA into GVL through a tandem reaction. Selection of this multistep complex reaction evidences the participation of the different acid sites (Lewis or Brønsted) of the material in each individual step: Brønsted-induced acid sites catalyze esterification reaction efficiently, while Lewis acid sites are the preferred sites for the MPV step. Sulfation of MOF-808 is used to enhance the Brønsted acidity of MOF-808, which improves the performance for esterification. However, the sulfate groups introduced are detrimental for the MPV step, since they reduce the intra-pore space available to form the required bulky transition state. These results evidence the need to find the best equilibrium between Brønsted and Lewis acid sites to optimize the outcome of this multistep reaction.


May-17-2021 Just accepted article in Chemistry - A European Journal:
One‐step Chemo‐, Regio‐ and Stereoselective Reduction of Ketosteroids to Hydroxysteroids over Zr‐containing MOF‐808 Metal‐organic Frameworks, doi.10.1002/chem.202100967
Zr‐containing MOF‐808 is a very promising heterogeneous catalyst for the selective reduction of ketosteroids to the corresponding hydroxysteroids through a Meerwein‐Ponndorf‐Verley (MPV) reaction. Interestingly, the process leads to the diasteroselective synthesis of elusive 17α‐hydroxy derivatives in one step, while most chemical and biological transformations produce the 17β‐OH compounds, or they require several additional steps to convert 17β‐OH into 17α‐OH by inverting the configuration of the 17 center. Moreover, MOF‐808 is found to be stable and reusable, and it is also chemoselective (only keto groups are reduced, even in the presence of other reducible groups such as C=C bonds) and regioselective (in 3,17‐diketosteroids only the keto group in position 17 is reduced, while the 3‐keto group remains almost intact). Kinetic rate constant and thermodynamic parameters of estrone reduction to estradiol have been obtained by a detailed temperature‐dependent kinetic analysis. The results evidence a major contribution of the entropic term, thus suggesting that the diastereoselectivity of the process is controlled by the confinement of the reaction inside the MOF cavities, where the Zr4+ active sites are located.


Sept-15-2020
Just accepted article in The Journal of Physical Chemistry C:
Visible-light driven photocatalytic coupling of benzylamine over titanium-based MIL-125-NH2 metal-organic framework: A mechanistic study, doi.10.1021/acs.jpcc.0c06950.

Imines are important building blocks in organic chemistry. Titanium-based metal-organic framework MIL-125-NH2(Ti) can photocatalyze, under visible light and at room temperature, the selective aerobic oxidation of benzylamine to N-benzylidenebenzylamine. We investigated the reaction mechanism using catalytic tests, ex situ infrared spectroscopy, and density functional calculations. In the dark, the presence of MIL-125-NH2(Ti) alone does not improve the reaction yield with respect to a blank experiment. This poor catalytic performance in the dark is associated to the absence of polarizing species on the MOF surface, as confirmed by acetonitrile adsorption. Excitation with different spectral regions evidenced the determinant role of the 450 < l < 385 nm range for the catalyst photoactivation. The calculations show that the last step of the reaction would have an energy barrier of 206 kJ mol-1 in anhydrous conditions, while it decreases to 91 kJ mol-1 only if the mechanism is mediated by two water molecules.




June-4-2020 Just accepted article in The Journal of Physical Chemistry Letters:
Tuning the catalytic properties of UiO-66 Metal-Organic Frameworks: From Lewis to defect-induced Bronsted acidity, J. Phys. Chem. Lett. 11 (2020) 4879-4890.

The Lewis/Brønsted acidity and catalytic properties of UiO-66-type metal–organic frameworks are studied in the context of tunable acid catalysts based on the presence of linker defects that create coordinatively unsaturated Zr4+ centers. Fourier transform infrared spectroscopy of adsorbed CO and direct pH measurements are employed to characterize hydrated and dehydrated UiO-66 containing different number of Zr4+ sites associated with defects. These sites can strongly polarize coordinated water molecules, which induces Brønsted acidity in the hydrated material. Upon dehydration of the solid, the coordinated water molecules are removed, and the underlying coordinatively unsaturated Zr4+ cations become exposed and available as Lewis acid sites. Herein we show, for various acid-catalyzed reactions, how it is possible to shift from a Brønsted acid to a Lewis acid catalyst by simply controlling the hydration degree of the solid. This control adds a new dimension to the design and engineering of MOFs for catalytic applications.






May-26-2020
Just accepted article in Inorganic Chemistry
Cobalt(II) Bipyrazolate Metal-Organic Framworks as Heterogeneous Catalysts in Cumene Aerobic Oxidation: A Tag-Dependent Selectivity, (doi: 10.1021/acs.inorgchem.0c00481)

Three metal–organic frameworks with the general formula Co(BPZX) (BPZX2– = 3-X-4,4′-bipyrazolate, X = H, NH2, NO2) constructed with ligands having different functional groups on the same skeleton have been employed as heterogeneous catalysts for aerobic liquid-phase oxidation of cumene with O2 as oxidant. O2 adsorption isotherms collected at pO2 = 1 atm and T = 195 and 273 K have cast light on the relative affinity of these catalysts for dioxygen. The highest gas uptake at 195 K is found for Co(BPZ) (3.2 mmol/g (10.1 wt % O2)), in line with its highest BET specific surface area (926 m2/g) in comparison with those of Co(BPZNH2) (317 m2/g) and Co(BPZNO2) (645 m2/g). The O2 isosteric heat of adsorption (Qst) trend follows the order Co(BPZ) > Co(BPZNH2) > Co(BPZNO2). Interestingly, the selectivity in the cumene oxidation products was found to be dependent on the tag present in the catalyst linker: while cumene hydroperoxide (CHP) is the main product obtained with Co(BPZ) (84% selectivity to CHP after 7 h, pO2 = 4 bar, and T = 363 K), further oxidation to 2-phenyl-2-propanol (PP) is observed in the presence of Co(BPZNH2) as the catalyst (69% selectivity to PP under the same experimental conditions).


Jan-23-2019
Just accepted article in ChemCatChem
Defect-Engineered Ruthenium MOFs as versatile heterogeneous hydrogenation catalysts, ChemCatChem, 12 (2020) 1-7.


Ruthenium MOF [Ru3(BTC)2Yy]·Gg (BTC = benzene-1,3,5-tricarboxylate ; Y = counter ions = Cl-, OH-, OAc-; G = guest molecules = HOAc, H2O) is modified via a mixed-linker approach, using mixtures of BTC and pyridine-3,5-dicarboxylate (PYDC) linkers, triggering structural defects at the distinct Ru2 paddlewheel (PW) nodes. This defect-engineering leads to enhanced catalytic properties due to the formation of partially reduced Ru2-nodes. Application of a hydrogen pre-treatment protocol to the Ru-MOFs, leads to a further boost in catalytic activity. We study the benefits of (1) defect engineering and (2) hydrogen pre-treatment on the catalytic activity of Ru-MOFs in the Meerwein-Ponndorf-Verleyreaction and the isomerization of allylic alcohols to saturated ketones. Simple solvent washing could not avoid catalyst deactivation during recycling for the latter reaction, while hydrogen treatment prior to each catalytic run proved to facilitate materials recyclability with constant activity over five runs.


July-23-2019
Just accepted article in Crystal Growth & Design:
Facile "green" aqueous synthesis of mono- and bimetallic trimesate metal-organic frameworks, (doi:  10.1021/acs.cgd.9b00237)

Various isoreticular mono- (Co2+, Ni2+, Cu2+ and Zn2+) and bimetallic (Co-Ni, Co-Zn, Mn-Ni) trimesate MOFs have been prepared by a fast (10 minutes) and green synthesis method from aqueous solutions, at room temperature and ambient pressure. A combined XRD and SEM/EDX analysis clearly revealed that bimetallic compounds for true solid solutions rather than a simple physical mixture of pure phase monometallic compounds. Moreover, a detailed evaluation of the evolution of cell parameters with the composition provides strong evidences indicating a preferential occupation of one crystallographic position (bidentate terminal sites) by Co2+ (or Mn2+) ions. This leads to a precise and predictable array of metal ions in the framework, which can be finely tuned by changing the overall composition of the bimetallic MOF. Implications are envisaged in the design and catalytic properties of well-defined single-site catalysts.


April-2-2019
Published book Chapter in RSC Catalysis Series:
"Cavity effects in Metal-Organic Frameworks", (Ch. 20, doi 10.1039/9781788016490-00440) in Noncovalent interactions in catalysis, RSC Catalysis Series No. 36. 978-1-78801-468-7 (2019)

Metal–organic frameworks (MOFs) have attracted enormous interest in recent years owing to their potential use as heterogeneous catalysts. MOF catalysts can be designed with active sites at the metallic units or at the organic ligands or trapped inside their regular pore system. This chapter illustrates how cavity effects (i.e. the chemical environment in which the active sites are located) can have a large influence on their final catalytic properties through specific host–guest interactions, thereby introducing additional tools to modulate chemical specificity.


April-2-2019

Just accepted article in ACS Sustainable Chemistry & Engineering:
Selective aerobic oxidation of cumene to cumene hydroperoxide over mono- and bimetallic trimesate Metal-Organic Frameowrks prepared by a facile "green" aqueous synthesis, (doi:  10.1021/acssuschemeng.8b06472)

Co–Ni and Mn–Ni bimetallic trimesate MOFs prepared by a fast aqueous synthesis method are excellent and reusable catalysts for the selective aerobic oxidation of cumene to cumene hydroperoxide (CHP). Isolation of Co2+ (or Mn2+) in an inert Ni-BTC framework is a good strategy to optimize CHP selectivity above 90%: since only Co2+ sites catalyze CHP decomposition, a drop of the CHP selectivity is observed as the cobalt content in the bimetallic MOF increases. The statistical probability of having isolated Co2+ sites is calculated as a function of the total cobalt content of the bimetallic compound, assuming homogeneous distribution of Co2+ ions in the Ni-BTC framework and preferential occupation of terminal sites. Thus, in our best sample, with a Co:Ni ratio of 5:95, 73% of the total Co2+ ions are isolated so that CHP decomposition/overoxidation processes at the surface of the catalyst are not likely to occur before CHP desorption. This can explain the excellent CHP selectivity (91%) attained over this material. This “site isolation” effect is further supported by similar findings on Mn–Ni bimetallic compounds.

July-26-2018

Just accepted article in Crystal Growth & Design:
Anion exchange and catalytic functionalization of the Zr-based metal organic framework DUT-67, (doi:  10.1021/acs.cgd.8b00832)

A postsynthetic treatment with diluted solutions of the inorganic HCl or H2SO4 acids was applied to functionalize the eight connected Zr-based metal–organic framework DUT-67 (DUT = Dresden University of Technology). During the treatment, it is possible to remove and exchange the pristine modulator (formate) by Cl or SO42– anions. The position of the chlorine in the crystal structure of DUT-67 after HCl treatment could be determined by single-crystal X-ray diffraction analysis. Moreover, by means of the acidic treatment the polarity of the network as well as its Brønsted acid strength are increased, which have a crucial impact on the catalytic performance. The improved catalytic activity of the acid-treated materials was demonstrated in the esterification of levulinic acid with ethanol.

June-22-2018

Just accepted article in Catalysis Science & Technology:
Catalytic properties of pristine and defect-engineered Zr-MOF-808 Metal  Organic Frameworks, (doi:  10.1039/C8CY00742J)

Various defect-engineered Zr-trimesate MOF-808 compounds (DE-MOF-808) have been prepared by mixing the tricarboxylate ligands with dicarboxylate ligands; viz. isophthalate, pyridine-3,5-dicarboxylate, 5-hydroxy-isophthalate, or 5-amino-isophthalate. The resulting mixed-ligand compounds, MOF-808-X (X = IP, Pydc, OH or NH2) were all found to be highly crystalline and isostructural to the unmodified MOF-808. Pristine MOF-808 showed better catalytic performance than a UiO-66 reference compound for the Meerwein-Ponndorf-Verley (MPV) reduction of carbonyl compounds. This was attributed to a higher availability of coordinatively unsaturated Zr4+ sites (cus) in MOF-808 upon removal of formate ions. Meanwhile, cus in UiO-66 are only located at defect sites and are thus much less abundant. Further improvement of the catalytic activity of defect-engineered MOF-808-IP and MOF-808-Pydc was observed, which may be related with the occurrence of less crowded Zr4+ sites in DE-MOF-808. The wider pore structure of MOF-808 with respect to UiO-66 compounds translate into a sharp improvement of the activity for the MPV reduction of bulky substrates, as shown for estrone reduction to estradiol. Interestingly, MOF-808 produces a notable diastereoselectivity towards the elusive 17-α-hydroxy estradiol.

January-11-2018

The impact of our work
Essential Science IndicatorsSM (January 2018): 8 Highly cited papers

#Citations
Engineering Metal Organic Frameworks (MOFs) for Heterogeneous Catalysis, Chem. Rev. 110 (2010) 46061831
Metal Organic Framework Catalysis: Quo vadis?, ACS Catal. 4 (2014) 361 324
Semiconductor behavior of a metal organic framework (MOF) 294
Metal-organic-framework nanosheets in polymer composite materials for gas separation applications, Nature Mater. 14 (2015) 48 296
(Research Front)
MOFs as catalysts: Activity, reusability and shape-selectivity of a Pd-containing MOF, J. Catal. 250 (2007) 294242
Water stable Zr-benzenedicarboxylate metal-organic frameworks as photocatalysts for hydrogen generation, Chem.Eur.J. 116 (2010) 11133227
Gold(III)-Metal Organic Framework bridges the gap between homogeneous and heterogeneous gold catalysts , J.Catal. 265 (2009) 155184
Metal-Organic and Covalent Organic Frameworks as single-site catalysts, Chem. Soc. Rev. 46 (2017) 3134. 12



May-12-2017
Just accepted article in CrystEngComm:
Base free transfer hydrogenation using a covalent triazine framework based catalyst (doi: 10.1039/C7CE00561J)



Isomerizarion of allylic alcohols to saturated ketones can be efficiently catalysed by a heterogeneous molecular system resulting from anchoring IrIIICp* to a Covalent Triazine Framework. The obtained catalysts are active, selective, and fully recyclable.


March-27-2017
Review article in Chemical Society Reviews
Metal–organic and covalent organic frameworks as single-site catalysts”, Chemical Society Reviews, 46 (2017) 3134.
Heterogeneous single-site catalysts consist of isolated, well-defined, active sites that are spatially separated in a given solid and, ideally, structurally identical. In this review, the potential of metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) as platforms for the development of heterogeneous single-site catalysts is reviewed thoroughly. In the first part of this article, synthetic strategies and progress in the implementation of such sites in these two classes of materials are discussed. Because these solids are excellent playgrounds to allow a better understanding of catalytic functions, we highlight the most important recent advances in the modelling and spectroscopic characterization of single-site catalysts based on these materials. Finally, we discuss the potential of MOFs as materials in which several single-site catalytic functions can be combined within one framework along with their potential as powerful enzyme-mimicking materials. The review is wrapped up with our personal vision on future research directions.

Nov-30-2016
Just accepted article in Chemistry- A European Journal
Encapsulation of bimetallic metal nanoparticles into robust Zr-based metal-organic frameworks: Evaluation of the catalytic potential for size-selective hydrogenation, Chem. Eur. J., in press.
The realization of metal NPs with bimetallic character and distinct composition for specific catalytic applications is an intensively studied field. Due to the synergy between metals, most of the bimetallic particles exhibit unique properties, only hardly provided by the individual monometallic counterparts. However, as small sized NPs possess high surface energy, agglomeration during catalytic reactions is favored. Sufficient stabilization can be achieved by confinement of NPs in porous support materials. In this sense, especially MOFs gained a lot of attention during the last years, however, encapsulation of bimetallic species remains challenging. Herein, the exclusive embedding of preformed core/shell PdPt and RuPt NPs into chemically robust Zr-based MOFs is presented. Microstructural characterization manifests partial retention of the core/shell systems after successful encapsulation without harming the crystallinity of the microporous support. The resulting chemically robust NP@UiO-66 materials exhibit enhanced catalytic activity towards the liquid-phase hydrogenation of nitrobenzene, competitive with commercially used Pt on activated carbon, but with simultaneous superior size-selectivity for sterically varying substrates.


Sept-7-2016

Our work on MOF nanosheets membranes has been distinguished with the 10th Duran Farrell Award of Technologigal Research

  • Fostered  by the Social Council of the Technical University of Catalonia and GAS NATURAL FENOSA, in tribute to the former president of Grupo Gas Natural, the prize aims to encourage research excellence.

A team of researchers of the Instituto de Tecnología Química (ITQ), a joint center of the Technical University of Valencia (UPV) and the Spanish National Research Council (CSIC), is the recipient of the 10th Pere Duran Farell prize of Technological Research, awarded by the Social Council of the Technical University of Catalonia (UPC) and GAS NATURAL FENOSA.

The prize aims to encourage research excellence by recognizing the quality of a research work carried out in Spain in any technological field during the last three years.

The winning project this year is entitled “Nanomaterials for gas separation: Mixed-matrix polymeric membranes based on metal organic nanosheets” and was carried out at the ITQ by the group lead by Dr. Francesc Xavier Llabrés i Xamena, Tenured Scientist of the CSIC.

The project falls within the field of gas separation through mixed membranes, specifically for the selective removal of CO2, which is related with greenhouse effect and global warming issues. In particular, the work proposes the use of metal organic frameworks (MOFs) in the form of nanosheets to optimize the distribution and orientation of the porous material throughout the polymeric membrane. In this way, it has been possible to prepare highly efficient and flexible ultrathin membranes with application not only in CO2 removal, but also in other fields, such as organic solar cells, synthetic fabrics, smart food packaging, as well as tactile screens and optoelectronic devices such as OLEDs. 
The jury has valued the trajectory of the project, as well as its innovative technological character and its contribution to scientific knowledge, along with its economic potential and societal impact. Collaboration with other researchers from prestigious international institutions, such as the Technical University of Delft and the Max Planck Institute, has also been highlighted by the jury.
 

Pere Duran Farell

This biannual prize was first awarded in 2000 in tribute to the prominent Catalonian entrepreneur and engineer Pere Duran Farrell (Caldes de Montbui, 1921- Barcelona, 1999), former president of Catalana de Gas and Gas Natural SDG, and promoter of the expansion and groth of Grupo Gas Natural, nowadays GAS NATURAL FENOSA. Honorary president of the energy group until his death, Pere Duran Farrell was the first president of the Social Council of the UPC. A visionary and main player of the Catalonian industrial policy of the XXth century, he also played a prominent humanistic role in several cultural and entrepreneurial projects of the country.




July-5-2016Just accepted article in European Journal of Inorganic Chemistry:
Diastereoselective synthesis of pyranoquinolines over Zr-containing UiO-66 metal organic frameworks, Eur. J. Inorg. Chem., 2016 (2016) 4512.


Zr-terephthalate MOFs UiO-66 and UiO-66-NH2 are found to be highly diastereoselective catalysts for the synthesis of pyrano[3,2-c]quinolines through an inverse electron-demand aza-Diels-Alder [4+2] cycloaddition of an aryl imine (formed in situ from aniline and an aldehyde) and 3,4-dihydro-2H-pyran in one pot, affording the corresponding trans isomer in 90-95% diastereomeric excess. The solids are stable under the reaction conditions and can be reused at least three times without significant loss of activity or diastereoselectivity.

July-5-2016
Just accepted article in Chemistry- A European Journal
Ruthenium Metal-Organic Frameworks with Different Defect Types: Influence on Porosity, Sorption and Catalytic Properties, Chem. Eur. J., 22 (2016) 14297.

Employing the mixed component, solid solution approach, various functionalized di-topic isophthalate (ip) defect generating linkers denoted as 5-X-ipH2, with X = OH (1), H (2), NH2 (3), Br (4) have been introduced into the mixed-valence ruthenium-analogue of [Cu3(btc)2] (HKUST-1) to yield Ru-DEMOFs (DE = “defect engineered”) of the general empirical formula [Ru3(btc)2-x(5-X-ip)xYy]n. The framework incorporation of 5-X-ip has been confirmed by a number of techniques including PXRD, FT-IR, UHV-IR, TGA, 1H-NMR, N2 sorption as well as XANES. Interestingly, Ru-DEMOF (1c) with 32% framework incorporation of 5-OH-ip reveals the highest BET surface area (~1300 m2/g, N2 adsorption, 77K) among all samples (including the parent framework [Ru3(btc)2Yy]n). The characterization data are consistent with two kinds of structural defects induced by 5-X-ip framework incorporation: type A, modified paddlewheel nodes featuring reduced ruthenium sites (Rud+, 0<δ<2) and type B: missing nodes leading to enhanced porosity. Their relative abundances depend on the choice of the functional group X in the defect linkers. The defects A and B appeared also to play a key role in sorption of small molecules (i.e., CO2, CO, H2) as well for the catalytic properties of the samples (i.e., ethylene dimerization and Paal-Knorr reaction).





May-27-2016On Friday we bid farewell to Fran and Olivia and wish them all the best


Last Friday, we said goodbye to two of our group mates: Olivia and Fran. Olivia will move back to the University of Namur, in Belgium, while Fran will start a new adventure as a post-doc in the group of a good friend of us, Dirk de Vos, at the Centre for Surface Chemistry and Catalysis at KU Leuven. To both of them, we wish them good luck and all the success in their work.

(From left to right: Olivia, Anna, Andrea, Hans-Hilmar, Víctor, Xesc and Fran).




July-21-2015Just published article in European Journal of Inorganic Chemistry
Pd@UiO-66-Type MOFs Prepared by Chemical Vapor Infiltration as Shape-Selective Hydrogenation CatalystsEur. J. Inorg. Chem., 2015 (2015) 3904-3912.
Host-guest inclusion properties of UiO-66 and UiO-67 metal-organic frameworks have been studied using ferrocene (FeCp2) as probe molecule. According to variable-temperature solid-state 1H and 13C CP-MAS-NMR, two different environments exist for adsorbed FeCp2 inside UiO-66 and UiO-67, which have been assigned to octahedral and tetrahedral cavities. At room temperature, a rapid exchange between these two adsorption sites occurs in UiO-67, while at –80 °C the intracrystalline traffic of FeCp2 through the triangular windows is largely hindered. In UiO-66, FeCp2 diffusion is already impeded at room temperature, in agreement with the smaller pore windows. Palladium nanoparticles (Pd NPs) encapsulated inside UiO-66 and UiO-67 have been prepared by chemical vapor infiltration of (allyl)Pd(Cp) followed by UV light irradiation. Infiltration must be carried out at low temperature (–10 °C) to avoid uncontrolled decomposition of the organometallic precursor and formation of Pd NPs at the external surface of the MOF. The resulting Pd-MOFs are shape selective catalysts, as shown for the hydrogenation of carbonyl compounds with different steric hindrance.


April-23-2015
Just published article in ACS Catalysis:
MIL-101 promotes benzylic oxidation of hydrocarbons exclusively by molecular oxygen in the absence of any other oxidizing reagent or initiator. Using indane as model compound, the selectivity towards the wanted ol/one mixture is higher for MIL-101(Cr) (87 % selectivity at 30 % conversion) than for MIL-101(Fe) (71 % selectivity at 30 % conversion), a fact that was associated to the preferential adsorption of indane within the pore system. Product distribution and quenching experiments with TEMPO, benzoic acid and dimethylformamide show that the reaction mechanism is a radical chain autooxidation of the benzylic positions by molecular oxygen and the differences in selectivity have been attributed to the occurrence of the autooxidation mostly process inside or outside the MOF pores. MIL-101 is reusable, does not leach metals to the solution, and maintains the crystal structure during the reaction. Apparent accumulated TON values based on the metal content as high as 155,100 with TOF value of 19,350 h-1 were determined for this process that is carried out in the total absence of any oxidizing reagent besides oxygen. The scope of the benzylic oxidation was expanded to other benzylic compounds including ethylbenzene, n-butylbenzene, iso-butylbenzene, 1-bromo-4-butylbenzene, sec-butylbenzene and cumene.

Nov-06-2014Volume 92 Issue 45 | p. 8 | News of The Week. Issue Date: November 10, 2014 | Web Date: November 6, 2014
Two-Dimensional MOFs boost Gas Separation

Materials: Thin sheets of metal-organic framework compounds improve membrane properties
By Mitch Jacoby
Read the complete news here.


Nov-03-2014 Our work in the media: UPV-News




Investigadores del Instituto de Tecnología Química, en colaboración con la Universidad Técnica de Delft y del Max Planck Institut, han conseguido un avance significativo en la tecnología de separación de gases mediante membranas. Para lograrlo, han utilizado unos materiales híbridos metal-orgánicos, conocidos como MOFs.
El uso de membranas para la separación de gases permite construir unidades de menor tamaño que el de otro tipo de instalaciones, como las de extracción con aminas, por lo que su impacto ambiental es también menor.
Esta nueva estrategia permitirá desarrollar membranas mixtas MOF-polímero ultrafinas con aplicaciones previstas en varios campos.
Los resultados obtenidos en este estudio y la descripción detallada del proceso utilizado para la preparación de estas membranas mixtas ultrafinas se recogen en un artículo que se publicará en breve en la revista Nature Materials y que ya puede consultarse on-line aquí.

Reference to the work

T. Rodenas, I. Luz, G. Prieto, B. Seoane, H. Miro, A. Corma, F. Kapteijn, F. X. Llabrés i Xamena and J. Gascon. Metal-organic-framework nanosheets in polymer composite materials for gas separation applications. Nature Materials (2014), doi: 10.1038/nmat4113