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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.
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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. |
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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.
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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 (nO
→ sS*) 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.
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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.
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Sept-21-2022 |
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Dec-25-2021 | Just 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 acid, Adv. 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-21-2021 | Just 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.
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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.
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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.
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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).
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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.
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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.
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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 (
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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.
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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.
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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.
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January-11-2018 |
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May-12-2017 |
Just accepted article in CrystEngComm: Base free transfer hydrogenation using a covalent triazine framework based catalyst (doi: 10.1039/C7CE00561J)
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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.
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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.
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Sept-7-2016 |
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July-5-2016 | Just 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.
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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).
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May-27-2016 | On 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-21-2015 | Just published article in European Journal of Inorganic Chemistry | |||||||||||||||||||||
Pd@UiO-66-Type MOFs Prepared by Chemical Vapor Infiltration as Shape-Selective Hydrogenation Catalysts, Eur. 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 |
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Nov-06-2014 | Volume 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 | |||||||||||||||||||||
Nov-03-2014 | Our work
in the media: UPV-News |
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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 |