A three-shell supramolecular complex enables the symmetry-mismatched chemo- and regioselective bis-functionalization of C60

Molecular Russian dolls (matryoshkas) have proven useful for testing the limits of preparative supramolecular chemistry but applications of these architectures to problems in other fields are elusive. Here we report a three-shell, matryoshka-like complex—in which C60 sits inside a cycloparaphenylene nanohoop, which in turn is encapsulated inside a self-assembled nanocapsule—that can be used to address a long-standing challenge in fullerene chemistry, namely the selective formation of a particular fullerene bis-adduct. Spectroscopic evidence indicates that the ternary complex is sufficiently stable in solution for the two outer shells to affect the addition chemistry of the fullerene guest. When the complex is subjected to Bingel cyclopropanation conditions, the exclusive formation of a single trans-3 fullerene bis-adduct was observed in a reaction that typically yields more than a dozen products. The selectivity facilitated by this matryoshka-like approach appears to be a general phenomenon and could be useful for applications where regioisomerically pure C60 bis-adducts have been shown to have superior properties compared with isomer mixtures.This work was supported by grants from MINECO-Spain (CTQ2016-77989-P and PID2019-104498GB-I00 to X.R., RTI2018-095622-B-100 to D.M. and I.I., and EUR2019-103824 to F.G.), Generalitat de Catalunya (2017SGR264 and a PhD grant to C.F.-E.) and the Severo Ochoa Center of Excellence Program (Catalan Institute of Nanoscience and Nanotechnology, grant SEV-2017-0706). X.R. is also grateful for ICREA-Acadèmia awards. M.v.D. is grateful for financial support from the Deutsche Forschungsgemeinschaft (project number 182849149-SFB953 ‘Synthetic Carbon Allotropes’), the Fonds der Chemischen Industrie (FCI), the University of Ulm and the Deutscher Akademischer Austauschdienst (PhD fellowship to O.B.). E.U. thanks Universitat de Girona for a PhD grant and we thank Serveis Tècnics de Recerca, Universitat de Girona for technical support.Peer reviewe

Multicomponent, Functionalized HKUST‑1 Analogues Assembled via Reticulation of Prefabricated Metal–Organic Polyhedral Cavities [Dataset]

89 pages. -- PDF file includes: S1. Materials and methods; S1.1. Materials and characterization; S1.2. Experimental methods; S1.2.1. Synthesis of COOH-RhMOP, (Br)btc, (NO2)btc and (COOH)btc; S1.2.2. Stability of COOH-RhMOP under solvothermal conditions; S1.2.3. Synthesis of RhCu-btc-HKUST-1, RhCu-(Br)btc-HKUST-1, RhCu-(NO2)btc-HKUST-1, RhCu-(NH2)btc-HKUST-1 and RhCu-(COOH)btc-HKUST-1; S.1.2.4. Blank reactions for RhCu-btc-HKUST-1; S.1.2.5. Acidic disassembly of RhCu-btc-HKUST-1; S.1.2.6. Acidic digestion of RhCu-(Br)btc-HKUST-1, RhCu-(NO2)btc-HKUST-1, RhCu-(NH2)btc-HKUST-1 and RhCu-(COOH)btc-HKUST-1; S1.2.7. Study of the hydrolytic stability of RhCu-btc-HKUST-1 and Cu(II)-HKUST- 1; S1.2.8 Study of the methylene blue removal with RhCu-btc-HKUST-1 and Cu(II)-HKUST-1; S1.2.9. Study of the catalytic activity of RhCu-btc-HKUST-1 and RhCu-(COOH)btc-HKUST-1; S1.3. Computational methods; S2. Characterization of RhCu-btc-HKUST-1; S3. Characterization of Cu(II)-HKUST-1; S4. Hydrolytic stability study of RhCu-btc-HKUST-1 and Cu(II)-HKUST-1; S4.1. DFT calculations of Rh(II) and Cu(II) paddlewheels in water; S5. Characterization of RhCu-(Br)btc-HKUST-1; S6. Characterization of RhCu-(NO2)btc-HKUST-1; S7. Characterization of RhCu-(NH2)btc-HKUST-1; S8. Characterization of RhCu-(COOH)btc-HKUST-1.Metal–organic frameworks (MOFs) assembled from multiple building blocks exhibit greater chemical complexity and superior functionality in practical applications. Herein, we report a new approach based on using prefabricated cavities to design isoreticular multicomponent MOFs from a known parent MOF. We demonstrate this concept with the formation of multicomponent HKUST-1 analogues, using a prefabricated cavity that comprises a cuboctahedral Rh­(II) metal–organic polyhedron functionalized with 24 carboxylic acid groups. The cavities are reticulated in three dimensions via Cu­(II)-paddlewheel clusters and (functionalized) 1,3,5-benzenetricarboxylate linkers to form three- and four-component HKUST-1 analogues.Peer reviewe

New Rare-earth Coordination Polymers as Multifunctional Materials

Tesis Doctoral elaborada en el Departamento de Síntesis y Estructura de Óxidos del Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC) y presentada en el Dpto. de Química-Física Aplicada de la Facultad de Ciencias de la Universidad Autónoma de Madrid el 25 de junio de 2009 para optar al grado de Doctor en Química.[EN] Los polímeros de coordinación son un tipo de compuestos en los que centros metálicos coordinan con ligandos orgánicos para dar lugar a estructuras que forman redes extensas en al menos una dirección del espacio. Durante los últimos quince años, la investigación centrada en este tipo de compuestos ha experimentado un gran desarrollo, debido a las potenciales aplicaciones que presentan. Así, se han sintetizado materiales que presentan estructuras abiertas con porosidad permanente, y su utilización como materiales para adsorción, separación y almacenamiento de gases está actualmente siendo objeto de estudio por numerosos grupos de investigación en todo el mundo. Otras aplicaciones para las que estos materiales están siendo investigados se encuentran dentro del área de la catálisis heterogénea, o en su uso como sensores, gracias a que pueden presentar, entre otras, propiedades ópticas, magnéticas, o de conducción. Dentro de la gran evolución que estos materiales han sufrido, la cristalografía y la cristaloquímica han jugado y juegan un papel determinante, tanto por permitir conocer las características estructurales de los nuevos materiales, como por ocuparse del entendimiento y racionalización de las nuevas redes formadas. En la actualidad, y a pesar de que en los últimos años ha habido una gran explosión en la aparición de nuevos polímeros de coordinación en la literatura, la investigación continúa centrada en la obtención racional de nuevos tipos estructurales diseñados para su aplicación en las áreas ya mencionadas.El presente trabajo ha sido realizado con el objetivo de preparar nuevos polímeros de coordinación utilizando elementos de las tierras raras y diversos ligandos orgánicos. En general, el uso de elementos de tierras raras está menos extendido en comparación con el de los metales de transición, principalmente debido a la variabilidad en la coordinación que presentan los primeros. Sin embargo, con la incorporación de estos metales dentro de los polímeros de coordinación se puede dotar a estos materiales con las interesantes propiedades de estos elementos. Entre los ligandos seleccionados encontramos un ligando dicarboxílico. Los ligandos con grupos carboxilato han demostrado ser capaces de formar estructuras robustas órgano-inorgánicas. El ligando utilizado en este trabajo ha sido seleccionado por sus características geométricas, ya que tiende a adoptar una conformación en forma de V. Ligandos con esta conformación no son muy comunes. Su uso ha sido anteriormente evaluado en nuestro grupo de investigación. En combinación con metales de transición ha dado lugar a estructuras con topologías poco habituales, debido sin duda a las características de la molécula. Su utilización para la construcción de polímeros de coordinación de tierras raras en el presente trabajo ha dado lugar a la formación de tres nuevos tipos estructurales, que resultan ser tres polimorfos de una misma fase. Nuevamente, las características del ligando se ven reflejadas en las topologías de estas nuevas redes.Por otro lado, el resto de ligandos utilizados presentan como grupo funcional al grupo sulfonato. El grupo sulfonato ha sido tradicionalmente considerado como poco apropiado para la construcción de polímeros de coordinación. Sin embargo, en nuestro grupo empezamos a evaluar sus posibilidades para la construcción de polímeros de coordinación con tierras raras. De esta forma se prepararon tres tipos estructurales, con buena estabilidad térmica e interesantes propiedades. Siguiendo con estos resultados obtenidos, nuevos tres ligandos con grupos sulfonatos han sido utilizados para la elaboración de este trabajo, dado lugar a la obtención de seis nuevos tipos estructurales. La comparación de estos nuevos resultados con los ya obtenidos permitirá extraer interesantes conclusiones sobre la preparación de polímeros de coordinación con tierras raras y ligandos sulfónicos. Además, todos estos nuevos materiales preparados presentan diferentes e interesantes propiedades, las cuales han sido evaluadas.Peer reviewe

Crystallography of metal-organic frameworks

Metal-organic frameworks (MOFs) are one of the most intensely studied material types in recent times. Their networks, resulting from the formation of strong bonds between inorganic and organic building units, offer unparalled chemical diversity and pore environments of growing complexity. Therefore, advances in single-crystal X-ray diffraction equipment and techniques are required to characterize materials with increasingly larger surface areas, and more complex linkers. In addition, whilst structure solution from powder diffraction data is possible, the area is much less populated and we detail the current efforts going on here. We also review the growing number of reports on diffraction under non-ambient conditions, including the response of MOF structures to very high pressures. Such experiments are important due to the expected presence of stresses in proposed applications of MOFs - evidence suggesting rich and complex behaviour. Given the entwined and inseparable nature of their structure, properties and applications, it is essential that the field of structural elucidation is able to continue growing and advancing, so as not to provide a rate-limiting step on characterization of their properties and incorporation into devices and applications. This review has been prepared with this in mind.FG acknowledges the Spanish Ministry of Economy and Competitiveness for funding through the `Juan de la Cierva' program. TDB thanks Trinity Hall (University of Cambridge) for funding

In Situ Transformation of TON Silica Zeolite into the Less Dense ITW: Structure-Direction Overcoming Framework Instability in the Synthesis of SiO2 Zeolites

Under specific synthesis conditions the crystallization of a dense silica zeolite (TON) is followed by its in situ transformation into a less dense and, in the absence of occluded species, less stable zeolite (ITW). Periodic ab initio calculations including energy corrections for van der Waals interactions as well as zero-point and thermal effects are used first to assess the relative stability of both SiO2 (calcined) phases and then to investigate host−guest interactions in the as-made zeolites, as well as their relative stability. The less dense SiO2-ITW is less stable than SiO2-TON, with an energy difference that is significantly larger than expected from their difference in molar volume. This extra destabilization is ascribed to the strained double 4-ring units of silica tetrahedra (D4R). Regarding the as-made materials, the organic cation fills in more efficiently the zeolitic voids in ITW than in TON, bringing about a larger stabilization in the former owing to the extension of the long-range addition of dispersion force contributions. On the other hand, fluoride induces a polarization of the silica framework that is highly localized in TON (showing pentacoordinated [SiO4/2F]− units) but has a large global character in ITW (where fluoride is encapsulated into D4R units). We argue that the structure-directing role toward D4R materials that has been proposed for fluoride consists fundamentally in the ability to induce a global polarization of the silica framework that allows relaxation of the strain associated with these units. In this sense, fluoride stabilizes the otherwise strained D4R-SiO2 frameworks making them reachable for crystallization. This work documents a case in which the structure directing agents “choose” a structure not kinetically but through stabilization.CICYT: MAT200603356 ConsoliderIngenio: CSD200600015 CONACYT: SEP0546983 FOMES2000 Project “Cómputo Científico"Peer reviewe

Chemistry of Covalent Organic Frameworks

ConspectusLinking organic molecules by covalent bonds into extended solids typically generates amorphous, disordered materials. The ability to develop strategies for obtaining crystals of such solids is of interest because it opens the way for precise control of the geometry and functionality of the extended structure, and the stereochemical orientation of its constituents. Covalent organic frameworks (COFs) are a new class of porous covalent organic structures whose backbone is composed entirely of light elements (B, C, N, O, Si) that represent a successful demonstration of how crystalline materials of covalent solids can be achieved. COFs are made by combination of organic building units covalently linked into extended structures to make crystalline materials. The attainment of crystals is done by several techniques in which a balance is struck between the thermodynamic reversibility of the linking reactions and their kinetics. This success has led to the expansion of COF materials to include organic units linked by these strong covalent bonds: B-O, C-N, B-N, and B-O-Si.Since the organic constituents of COFs, when linked, do not undergo significant change in their overall geometry, it has been possible to predict the structures of the resulting COFs, and this advantage has facilitated their characterization using powder X-ray diffraction (PXRD) techniques. It has also allowed for the synthesis of COF structures by design and for their formation with the desired composition, pore size, and aperture. In practice, the modeled PXRD pattern for a given expected COF is compared with the experimental one, and depending on the quality of the match, this is used as a starting point for solving and then refining the crystal structure of the target COF. These characteristics make COFs an attractive class of new porous materials. Accordingly, they have been used as gas storage materials for energy applications, solid supports for catalysis, and optoelectronic devices. A large and growing library of linkers amenable to the synthesis of COFs is now available, and new COFs and topologies made by reticular synthesis are being reported. Much research is also directed toward the development of new methods of linking organic building units to generate other crystalline COFs. These efforts promise not only new COF chemistry and materials, but also the chance to extend the precision of molecular covalent chemistry to extended solids

High volumetric uptake in aluminum metal-organic frameworks

This paper was presented at the 1st International Symposium on Energy, Challenges & Mechanics (2014) that was held in Aberdeen (Scotland) on 8-10th July 2014.Methane is the main component of natural gas. Currently there is a great interest in the use of natural gas as fuel for automobiles because of its availability and lower carbon emissions, compared to petroleum. Therefore, there is an extensive work to find materials able to efficiently store and deliver large amounts of methane at operation conditions that can be implemented for on-boards applications. Metal-organic Frameworks, MOFs, are known to be useful in the storage of gases. Here we report the synthesis, crystal structure, porosity and methane adsorption properties of two new aluminum based MOFs, MOF-519, Al8(OH)8(BTB)4(H2BTB)4, and MOF-520, Al8(OH)8(BTB)4(HCOO)4 (BTB = 4,4ʹ,4ʹʹ-benzene-1,3,5-tryil-tribenzoate). Both materials are built from octametallic aluminum SBUs that are linked by the tritopic BTB linker to produce extended three dimensional structures. These structures are highly porous, with Langmuir surface area values of 2660 and 3630 m2 g-1 for MOF-519 and MOF-520, respectively. MOF-519 has the largest total volumetric uptake at 80 bar and 298 K reported for any MOF, being able to store 279 cm3 cm-3. In addition, its working capacity, defined as the amount of methane that can be delivered in the operational pressure range, is 230 cm3 cm-3 between 5-80 bar at 298 K

Stable organic radical stacked by in situ coordination to rare earth cations in MOF materials

With the correct choice of the solvothermal conditions, we have achieved the unprecedented in situ formation of the free radical form of the anthraquinone-1,5-disulfonate molecule, and its favorable organization. The semiquinone radicals are coordinated to rare-earth cations to produce a 2D framework with a very high charge mobility and electric conductivity through the π-π-interactions. The existence of AQDS 3- anion radicals is proven on the base of: i) the electrical neutrality: elemental analyses for the different lanthanide RPF-8 bulks, the maximum residual electron densities in the structure, rule out the existence of any other neutralizing ion, ii) the geometrical modifications in the antraquinone molecules, and iii) although less definitive, due to the low magnetic moment μ = 0.39 μ B, the exhibited paramagnetism for the La (3+) with no unpaired electrons. © 2012 The Royal Society of Chemistry.This work has been supported by Spanish MCYT Projects Mat 2007-60822, 2010-17571, and 2008-06542-C04, the Project Consolider-Ingenio CSD2006-2001, and the Project of Comunidad Autónoma de Madrid (S2009/MAT-1756).Peer Reviewe

Fundamental Insights into Photoelectrocatalytic Hydrogen Production with a Hole-Transport Bismuth Metal–Organic Framework

[EN] Solar fuels production is a cornerstone in the development of emerging sustainable energy conversion and storage technologies. Light-induced H2 production from water represents one of the most crucial challenges to produce renewable fuel. Metalorganic frameworks (MOFs) are being investigated in this process, due to the ability to assemble new structures with the use of suitable photoactive building blocks. However, the identification of the reaction intermediates remains elusive, having negative impacts in the design of more efficient materials. Here, we report the synthesis and characterization of a new MOF prepared with the use of bismuth and dithieno[3,2-b:2',3'-d]thiophene-2,6-dicarboxylic acid (DTTDC), an electron-rich linker with hole transport ability. By combining theoretical studies and time-resolved spectroscopies, such as core hole clock and laser flash photolysis measurements, we have completed a comprehensive study at different time scales (fs to-ms) to determine the effect of competitive reactions on the overall H2 production. We detect the formation of an intermediate radical anion upon reaction of photogenerated holes withan electron donor, which plays a key role in the photoelectrocatalytic processes. These results shed new light on the use of MOFs for solar fuel production.This work was supported by the EU (ERC CoG HyMAP 648319) and Spanish MCIU, Ra-Phuel (ENE2016-79608-C2-1-R), SOLPAC (ENE2017-89170-R) FOTOFUEL (ENE2016-82025-REDT) and CTQ2017-87262-R (MCIU/AEI/FEDER, UE). We thank "Comunidad de Madrid" and European Structural Funds for their financial support to FotoArt-CM project (S2018/NMT-4367). F.G., M. L and M. B thank to MINECO and European Social Fund for a Ramón y Cajal contract (RyC-2015-18384, RyC-2015-18677) and Juan de la Cierva Formación contract (FJCI-2016-30567), respectively. We thank Diamond Facilities for the access to synchrotron radiation and CESCA for computational resources.Peer reviewe

Encoding Metal-Cation Arrangements in Metal-Organic Frameworks for Programming the Composition of Electrocatalytically Active Multimetal Oxides

[EN] In the present contribution, we report how through the use of metal-organic frameworks (MOFs) composed of addressable combinations of up to four different metal elements it is possible to program the composition of multimetal oxides, which are not attainable by other synthetic methodologies. Thus, due to the ability to distribute multiple metal cations at specific locations in the MOF secondary building units it is possible to code and transfer selected metal ratios to multimetal oxides with novel, desired compositions through a simple calcination process. The demonstration of an enhancement in the electrocatalytic activity of new oxides by preadjusting the metal ratios is here reported for the oxygen reduction reaction, for which activity values comparable to commercial Pt/C catalysts are reached, while showing long stability and methanol tolerance.We acknowledge Institut Laue-Langevin and Spanish Initiatives on Neutron Scattering (ILL-SpINS) for beamtime at instrument D1B and G. Cuello for assistance during data acquisition. The Paul Scherrer Institute is also acknowledged for beamtime at instrument HRPT and V. Pomjakhusin for assistance during data acquisition. We thank E. Rodríguez-Cañas and Isidoro Poveda from the Servicio Interdepartamental de Investigación at Universidad Autónoma de Madrid for valuable support with SEM images and EDS analyses and FE-SEM image acquisition, respectively. We acknowledge E. Urones for the TEM images and TEM-EDS analysis acquisition at Centro Nacional de Microscopía Electrónica. Funding: Work at Instituto de Ciencia de Materiales de Madrid−Consejo Superior de Investigaciones Cientifícas (CSIC) has been supported by the Spanish Ministry for Science, Innovation and Universities (MINECO), and FEDER funds: Projects MAT2016-78465-R, MAT2015-68639-R, and CTQ2017-87262-R. F.G. and N.L.-S. acknowledge financial support from MINECO (Ramón y Cajal program and FPI research contract, respectively)