51 research outputs found

    Adsorptive Separation of CO2 by a Hydrophobic Carborane-Based Metal-Organic Framework under Humid Conditions

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    We report that the carborane-based metal-organic framework (MOF) mCB-MOF-1 can achieve high adsorptive selectivity for CO2:N2 mixtures. This hydrophobic MOF presenting open metal sites shows high CO2 adsorption capacity and remarkable selectivity values that are maintained even under extremely humid conditions. The comparison of mCB-MOF-1' with MOF-74(Ni) demonstrates the superior performance of the former under challenging moisture operation conditions

    Copper complexes from 3,5-disubstituted N-hydroxyethylpyrazole ligands: Cleavage of C-N bond as well as formation of second coordination sphere complexes

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    The coordination behaviour of two N,O-hybrid hydroxyethylpyrazole ligands, 2-(3,5-diphenyl-1H-pyrazol-1-yl)ethanol, HL1; and (2-(3,5-di(2-pyridyl)-1H-pyrazol-1-yl)ethanol, HL2; with CuCl2·2H2O and Cu(NO3)2·3H2O were studied. Four copper complexes: [CuCl(µ-L1)]2·HL1 (1), [CuCl2(HL2)]·H2O (2A), [Cu(NO3)(3,5-hdppz)(µ-L1)]2·2CH3CN (3), (3,5-hdppz = 3,5-diphenylpyrazole) and [Cu(H2O)(3,5-dpypz)]2(NO3)2·H2O (4), (3,5-dpypz = 3,5-(2-pyridyl)pyrazolate) were isolated and characterized by analytical methods and spectroscopical studies. From their crystal structure, a Npz-C bond cleavage was observed for HL1 and HL2 upon reaction with Cu(NO3)2·3H2O, yielding the unexpected complexes 3 and 4, respectively. Overall, these complexes provided great structural diversity, as dimers (asymmetric and symmetric), monomers and ionic complexes were obtained. Finally, magnetic susceptibility measurements for 3 were carried out, showing the dependence of the magnetic moment on Cu-O-Cu angles

    Nuevos carboranil alcoholes que contienen anillos aromáticos nitrogenados : síntesis, caracterización, análisis estructural y estudios preliminares de reactividad

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    Se han sintetizado nueve alcoholes que incorporan diversos isómeros de los grupos piridil o quinolil y metil-o-carborano u o-carborano, 1-[n'-Piridil(hidroxi)metil]-2-R-1,2-dicarba-closo-dodecaboranos (n' = 2, R = H (2a); n' = 3, R = Me (1c) y H (2c)), 1-[2'-6-metil-piridil(hidroxi)metil]-2-R-1,2-dicarba-closo-dodecaboranos (R = Me (1b) y H (2b)), 1-[n'-Quinolil(hidroxi)metil]-2-R-1,2-dicarba-closo-dodecaboranos (n' = 2, R = Me (1e) y H (2e); n' = 4, R = Me (1f) y H (2f), mediante la adición de la sal de litio del metil-o-carborano u o-carborano a los aldehídos correspondientes. Los compuestos se han obtenido con rendimientos altos en la mayoría de los casos y han sido caracterizados mediante Resonancia Magnética Nuclear, por Espectroscopía Infrarroja y análisis elemental. Las estructuras cristalinas de siete de los nueve compuestos (1c, 1f, 2a, 2b, 2c, 2e y 2f) se han determinado mediante Cristalografía por Rayos X. Se han analizado las estructuras cristalinas de los todos los compuestos y se han comparado con las estructuras de los compuestos relacionados 1a, 1b, y 2a, obtenidas previamente en el grupo de Síntesis Inorgánica y Catálisis del ICMAB. Todas las estructuras muestran interacciones por puentes de hidrógeno O-H···N moderadamente fuertes. Posteriormente se ha sintetizado el derivado mesilado 4 (derivado del o-carborano) mediante la reacción del alcohol 2a con cloruro de mesitilo a temperatura ambiente, con rendimiento alto. El nuevo mesilato 4 se ha caracterizado mediante Resonancia Magnética Nuclear. El nuevo mesilato resulta un compuesto de partida muy versátil para la síntesis de nuevos derivados mediante la substitución del grupo mesilo por nucleófilos apropiados, como por ejemplo las aminas. El grupo ha publicado recientemente la síntesis de diaminas mediante la reacción de substitución del mesilato relacionado 3 (derivado del metil-o-carborano) con aminas, entre ellas la bencilamina. Se ha realizado por tanto la reacción de substitución del grupo mesilato en 4 por la bencilamina para obtener la diamina correspondiente. Los resultados preliminares de esta reacción muestran que si bien el grupo mesilato en 4 ha sido substituido, el clúster se degrada casi en su totalidad a un derivado tipo nido. Esto contrasta claramente con la reactividad del mesilato análogo 3 frente a la bencilamina, ya que en este caso se obtiene la diamina deseada y el clúster no se degrada apreciablemente bajo las mismas condiciones de reacción. Se han realizado estudios preliminares por RMN que muestran que la bencilamina substituye al grupo mesilo en 4 y posteriormente el clúster closo se degrada a una especie nido que no ha sido posible caracterizar totalmente hasta el momento

    Tuning the architectures and luminescence properties of Cu(I) compounds of phenyl and carboranyl pyrazoles: the impact of 2D versus 3D aromatic moieties in the ligand backbone

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    This work was financially supported by MICINN (PID2019-106832RB-I00, PGC2018-093863-B-C21), MICINN through the Severo Ochoa Program for Centers of Excellence for the FUNFUTURE (CEX2019-000917-S and MDM-2017-0767 projects) and the Generalitat de Catalunya (2017/SGR/1720 and SGR2017-1289). D. Ch.-L. acknowledges funding by project no. PGC2018-102047-B-I00 (MCIU/AEI/FEDER, UE). J. Soldevila-Sanmartin is enrolled in the UAB PhD program and acknowledges the PIF pre-doctoral Fellowship from the UAB for his pre-doctoral grant (no. 19032/2). E. R. acknowledges computer resources, technical expertise and assistance provided by the CSUC. We thank Prof. D. Ruiz and Dr C. Roscini for the quantum yield measurements. The present publication is dedicated to Prof. Elena Shubina on the occasion of her 70th birthday.Incorporation of one or two o-carborane moieties at the backbone of the pyrazole ring was achieved by lithiation and nucleophilic addition onto the corresponding 3,5-dimethyl-1-(2-toluene-p-sulfonyloxyethyl)pyrazole. Two monosubstituted carboranyl pyrazoles (L2 and L3) and one disubstituted carboranyl pyrazole (L4) were synthesized and fully characterized. All new compounds, and the corresponding monosubstituted phenylderivative (L1) behave as N-type ligands upon coordination with CuI to afford different polynuclear Cu(I) compounds 1-4. Compounds 1-4 were fully characterized and their molecular structures were determined by X-ray diffraction. It is noteworthy that whereas the pyrazolylphenyl ligand L1, without o-carborane, provides a 1D coordination polymer (1), ligands containing carborane, L2-L3, affords 0D coordination compounds 2 and 3, and disubstituted carboranyl pyrazole ligand L4 gives rise to a 3D coordination polymer. The photoluminescence behaviour of compounds 1-4 has been investigated in the solid state and by TDDFT calculations for molecular compounds 2 and 3. Complex 2 exhibits blue emission with a maximum at 483 nm and a high fluorescence quantum yield of 66.5%. According to TDDFT calculations the emission occurs from LUMO to HOMO-1 and HOMO-2 and deexcitation could be described as cluster-centred excited state of d-s transition in origin. This result contradicts previous studies of scarce tri-coordinated rhombohedral Cu(I) clusters, where it was assumed the origin of their emissions is (X + M)LCT in nature by analogy with tetra-coordinated rhombohedral Cu(I) clusters. Complex 3 exhibits very weak emission (Phi(F) of 5%) in the green region with a maximum at 517 nm, which according to TDDFT is through a (CC)-C-3 state. Calculations also show that, upon excitation, 3 suffers a notable distortion resulting in the total cleavage of the Cu4I4 framework. This cleavage could be the cause of the relatively large Stokes shift observed for 3. To the best of our knowledge, this is the first time that such behaviour is observed for this type of octahedral compounds. Additionally, the 1D polymer 1 exhibits weak fluorescence emission in the orange range with a maximum at 609 nm and a remarkable Stokes shift, whereas the 3D polymer 4 exhibits a similar emission to compound 2, with a moderate quantum yield (FF of 13.7%).Spanish Government European Commission PID2019-106832RB-I00 PGC2018-093863-B-C21MICINN through the Severo Ochoa Program for Centers of Excellence for the FUNFUTURE CEX2019-000917-S MDM-2017-0767Generalitat de Catalunya 2017/SGR/1720 SGR2017-1289MCIU/AEI/FEDER, UE PGC2018-102047-B-I00UAB 19032/

    An unprecedented stimuli-controlled single-crystal reversible phase transition of a metal-organic framework and its application to a novel method of guest encapsulation

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    The flexibility and unexpected dynamic behavior of a third-generation metal- organic framework are described for the first time. The synthetic strategy is based on the flexibility and spherical shape of dipyridyl-based carborane linkers that act as pillars between rigid Co/BTB (BTB: 1,3,5-benzenetricarboxylate) layers, providing a 3D porous structure (1). A phase transition of the solid can be induced to generate a new, nonporous 2D structure (2) without any loss of the carborane linkers. The structural transformation is visualized by snapshots of the multistep single-crystal-to-single-crystal transformation by single-crystal and powder X-ray diffraction. Poor hydrogen bond acceptors such as MeOH, CHCl3 or supercritical CO2 induce such a 3D to 2D transformation. Remarkably, the transformation is reversible and the 2D phase 2 is further converted back into 1 by heating in dimethylformamide. The energy requirements involved in such processes are investigated using periodic density functional theory calculations. As a proof of concept for potential applications, encapsulation of C60 is achieved by trapping this molecule during the reversible 2D to 3D phase transition, whereas no adsorption is observed by straight solvent diffusion into the pores of the 3D phase

    A Metal-Organic Framework Incorporating Eight Different Size Rare-Earth Metal Elements: Toward Multifunctionality À La Carte

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    Multi‐metallic multivariate (MTV) rare earth (RE) metal−organic frameworks (MOFs) are of interest for the development of multifunctional materials, however examples with more than three RE cations are rare and obstructed by compositional segregation during synthesis. Herein, this work demonstrates the synthesis of a multi‐metallic MTV RE MOF incorporating two, four, six, or eight different RE ions with different sizes and in nearly equimolar amounts and no compositional segregation. The MOFs are formed by a combination of RE cations (La, Ce, Eu, Gd, Tb, Dy, Y, and Yb) and a 1,7‐di(4‐carboxyphenyl)‐1,7‐dicarba‐closo‐dodecaborane (mCB‐L) linker. The steric bulkiness and acidity of mCB‐L is crucial for the incorporation of different size RE ions into the MOF structure. Demonstration of the incorporation of all RE cations is performed via compositional and structural characterization. The more complex MTV MOF, including all eight RE ions (mCB‐8RE), are also characterized using optical, thermal, and magnetic techniques. Element‐selective X‐ray absorption spectroscopy and X‐ray Magnetic Circular Dichroism measurements allow us to characterize spectroscopically each of the eight RE ions and determine their magnetic moments. This work paves the way for the investigation of MTV MOFs with the possibility to combine RE ions à la carte for diverse applications

    Carborane bis-pyridylalcohols as linkers for coordination polymers : synthesis, crystal structures and guest-framework dependent mechanical properties

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    We report the synthesis and characterization of six novel coordination polymers (CPs) based on M(II) (M: Zn and Co), di-, tri-, and tetracarboxylate linkers and two novel bis-pyridylalcohol 1,7-bis{(pyridin-n'-yl)methanol}-1,7-dicarba-closo-dodecaboranes (n' = 3, L1; n' = 4, L2) ligands. The polycarboxylates are terephthalic acid (H₂BDC), 1,3,5-benzenetricarboxylic acid (H₃BTB), and 1,2,4,5-tetrakis(4-carboxyphenyl)benzene (H₄TCPB). Structural description of CPs reveals the flexibility of the carborane ligands and their ability to construct extended structures. The CP containing Co(II), BTB, and L2 behaves as a crystalline sponge for a variety of guests, showing a higher affinity for aromatic guest molecules. Single-crystal nanoindentation experiments indicate that a high number of specific interactions between the guests and the CP framework result in a high elastic modulus and hardness values

    Switchable surface hydrophobicity–hydrophilicity of a metal–organic framework

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    Materials with surfaces that can be switched from high/superhydrophobicity to superhydrophilicity are useful for myriad applications. Herein, we report a metal–organic framework (MOF) assembled from Zn ions, 1,4-benzenedicarboxylate, and a hydrophobic carborane-based linker. The MOF crystal-surface can be switched between hydrophobic and superhydrophilic through a chemical treatment to remove some of the building blocks.This work was supported by the EU FP7 ERC-Co 615954.M.Y.T., F.T. , C.V., and J.G.P. thank MINECO grants CTQ2013-44670-R and the Generalitat de Catalunya (2014/SGR/149) for financial support. The Intramural CSIC (201530E011) provided X-ray structural facilities for this work. I.I. thanks the MINECO for a RyC fellowship and V. G. is grateful to the Generalitat de Catalunya for a Beatriu de Pinos Fellowship. ICMAB and ICN2 acknowledge the support of the Spanish MINECO through the Severo Ochoa Centers of Excellence Program, under Grant SEV-2015-0496 and SEV-2013-0295Peer Reviewe

    Switchable Surface Hydrophobicity-Hydrophilicity of a Metal-Organic Framework

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    Materials with surfaces that can be switched from high/superhydrophobicity to superhydrophilicity are useful for myriad applications. Herein, we report a metal-organic framework (MOF) assembled from Znions, 1,4-benzenedicarboxylate, and a hydrophobic carborane-based linker. The MOF crystal-surface can be switched between hydrophobic and superhydrophilic through a chemical treatment to remove some of the building blocks

    Epidemiological trends of HIV/HCV coinfection in Spain, 2015-2019

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    Altres ajuts: Spanish AIDS Research Network; European Funding for Regional Development (FEDER).Objectives: We assessed the prevalence of anti-hepatitis C virus (HCV) antibodies and active HCV infection (HCV-RNA-positive) in people living with HIV (PLWH) in Spain in 2019 and compared the results with those of four similar studies performed during 2015-2018. Methods: The study was performed in 41 centres. Sample size was estimated for an accuracy of 1%. Patients were selected by random sampling with proportional allocation. Results: The reference population comprised 41 973 PLWH, and the sample size was 1325. HCV serostatus was known in 1316 PLWH (99.3%), of whom 376 (28.6%) were HCV antibody (Ab)-positive (78.7% were prior injection drug users); 29 were HCV-RNA-positive (2.2%). Of the 29 HCV-RNA-positive PLWH, infection was chronic in 24, it was acute/recent in one, and it was of unknown duration in four. Cirrhosis was present in 71 (5.4%) PLWH overall, three (10.3%) HCV-RNA-positive patients and 68 (23.4%) of those who cleared HCV after anti-HCV therapy (p = 0.04). The prevalence of anti-HCV antibodies decreased steadily from 37.7% in 2015 to 28.6% in 2019 (p < 0.001); the prevalence of active HCV infection decreased from 22.1% in 2015 to 2.2% in 2019 (p < 0.001). Uptake of anti-HCV treatment increased from 53.9% in 2015 to 95.0% in 2019 (p < 0.001). Conclusions: In Spain, the prevalence of active HCV infection among PLWH at the end of 2019 was 2.2%, i.e. 90.0% lower than in 2015. Increased exposure to DAAs was probably the main reason for this sharp reduction. Despite the high coverage of treatment with direct-acting antiviral agents, HCV-related cirrhosis remains significant in this population
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