Síntesis de materiales reticulares metal-orgánicos para su aplicación como catalizadores heterogéneos con interés industrial y medioambiental

En la presente tesis doctoral se ha estudiado la aplicación de los MOFs de las fa-milias MIL-101 y UiO-66 como catalizadores heterogéneos y su facilidad para ser modificados tanto sintéticamente como post-sintéticamente, bien sea intercambiando un porcentaje de metal del nodo, como modificando el ligando introduciendo grupos electrodadores o electroaceptores, demostrando además la posibilidad de combinar ambas estrategias. En particular, la tesis se centra en la aplicación de los MOFs como catalizadores heterogéneos para reacciones de oxidación aeróbica, como la oxidación de compuestos bencílicos, de dibenzotiofenos, de bencilaminas o de alquenos, y reacciones de catálisis ácido de Lewis como la reacción de Prins, la apertura de epóxidos o la acetalización. A la vista de los resultados obtenidos se ha demostrado que los MOFs son catali-zadores y promotores de reacciones de oxidación aeróbica que trascurren a través de especies reactivas de oxígeno como fundamentalmente hidroperóxido e hidroxilo sin sufrir degradación o descomposición. También, se ha demostrado, que estos materiales en las condiciones de reacción empleadas no sufren desactivación con los reusos, ya que no se produce prácticamente lixiviado de metal a la fase líquida durante las reac-ciones y además mantienen la cristalinidad después de varios cíclos catalíticos. Además, se ha observado que la presencia de sustituyentes fuertemente aceptores de electrones aumentan la actividad catalítica de estos materiales para reacciones que implican los átomos metálicos, bien sea ácido-base o reacciones de oxidación aeróbica.En la present tesis doctoral se ha estudiat l'aplicació dels MOFs de les famílies MIL-101 y UiO-66 com a catalitzadors heterogenis y la seua facilitat per a ser modifi-cats tant sintèticament como post-sintèticament, be siga intercanviant un percentatge de metall del node, como modificant el lligand introduint grups electrodadors o elec-troaceptors, demostrant a més la possibilitat de combinar ambdues estratègies. En particular, la tesis es centra en la aplicació dels MOFs como a catalitzadors heterogenis per a reaccions d'oxidació aeròbica, como l'oxidació de compostos bencí-lics, de dibenzotiofens, de bencilamines o d'alquens, y reaccions de catàlisis d'àcid de Lewis com la reacció de Prins, la apertura de epòxids o la acetalització. En vista dels resultats obtinguts s'ha demostrat que els MOFs son catalitzadors y promotors de reaccions d'oxidació aeròbica que tenen lloc a través d'espècies reactives d'oxigen com fonamentalment hidroperòxid e hidroxil sense sofrir degradació o des-composició. També, s'ha demostrat, que estos materials en les condicions de reacció empleades no experimenten desactivació amb els reusos, ja que no es produeix pràcti-cament lixiviat de metall a la fase líquida durant les reaccions i a més, mantenen la cristalinitat després de diversos cicles catalítics. A més, s'ha observat que la presència de substituents fortament acceptors d'electrons augmenten l'activitat catalítica d'estos materials per a reaccions que impli-quen els àtoms metàl·lics, be siga àcid-base o reaccions d'oxidació aeròbica. ¿In the present doctoral thesis, we study the application of the MOFs MIL-101 and UiO-66 families as heterogeneous catalysts and their ease to be modified both syn-thetically and post-synthetically, either by exchanging a percentage of the metal of the node, as modifying the ligand introducing electron donors or electron acceptors groups, demonstrating also the possibility of combining both strategies. Particularly, the thesis focuses on the application of MOFs as heterogeneous cata-lysts for aerobic oxidation reactions, such as the oxidation of benzylic compounds, dibenzothiophenes, benzylamines or alkenes, and Lewis acid catalysis reactions such as Prins reaction, ring opening of epoxies or acetalization of benzaldehyde. In view of the results obtained, it has been demonstrated that MOFs are catalysts and promoters of aerobic oxidation reactions that pass through reactive oxygen species such as hydroperoxide and hydroxyl without suffering degradation or decomposition. Also, it has been demonstrated that these materials under the reaction conditions used do not undergo deactivation with reuse, since there is practically no leaching of metal to the liquid phase during the reactions and they also maintain the crystallinity after several catalytic cycles. In addition, it has been observed that the presence of strongly electron-accepting substituents increases the catalytic activity of these materials for reactions involving the metal atoms, either acid-base or aerobic oxidation reactions.Santiago Portillo, A. (2018). Síntesis de materiales reticulares metal-orgánicos para su aplicación como catalizadores heterogéneos con interés industrial y medioambiental [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/114829TESI

Subphthalocyanine encapsulated within MIL-101(Cr)-NH2 as a solar light photoredox catalyst for dehalogenation of alpha-haloacetophenones

[EN] Subphthalocyanine has been incorporated into a robust metal-organic framework having amino groups as binding sites. The resulting SubPc@MIL-101(Cr)-NH2 composite has a loading of 2 wt%. Adsorption of subphthalocyanine does not deteriorate host crystallinity, but decreases the surface area and porosity of MIL-101(Cr)-NH2. The resulting SubPc@MIL-101(Cr)-NH2 composite exhibits a 575 nm absorption band responsible for the observed photoredox catalytic activity under simulated sunlight irradiation for hydrogenative dehalogenation of alpha-haloacetophenones and for the coupling of alpha-bromoacetophenone and styrene. The material undergoes a slight deactivation upon reuse. In comparison to the case of phthalocyanines the present study is one of the few cases showing the use of subphthalocyanine as a photoredox catalyst, with its activity derived from site isolation within the MOF cavities.Financial support from the Spanish Ministry of Economy and Competitiveness (Severo Ochoa and RTI2018-098237-B-C21) and Generalitat Valenciana (Prometeo 2017-083) is gratefully acknowledged. S. N. is thankful for the financial support from the Fundacion Ramon Areces (XVIII Concurso Nacional para la Adjudicacion de Ayudas a la Investigacion en Ciencias de la Vida y de la Materia, 2016), the Ministerio de Ciencia, Innovacion y Universidades RTI 2018-099482-A-I00 project and the Generalitat Valenciana grupos de investigacion consolidables 2019 (ref: AICO/2019/214) project. S. R.-B. also thanks the Research Executive Agency (REA) and the European Commission for the funding received under the Marie Sklodowska Curie actions (H2020-MSCA-IF-2015/Grant agreement number 709023/ZESMO).Santiago-Portillo, A.; Remiro-Buenamañana, S.; Navalón Oltra, S.; García Gómez, H. (2019). Subphthalocyanine encapsulated within MIL-101(Cr)-NH2 as a solar light photoredox catalyst for dehalogenation of alpha-haloacetophenones. Dalton Transactions. 48(48):17735-17740. https://doi.org/10.1039/c9dt04004hS17735177404848Deng, X., Li, Z., & García, H. (2017). Visible Light Induced Organic Transformations Using Metal-Organic-Frameworks (MOFs). Chemistry - A European Journal, 23(47), 11189-11209. doi:10.1002/chem.201701460Dhakshinamoorthy, A., Asiri, A. M., & García, H. (2016). Metal-Organic Framework (MOF) Compounds: Photocatalysts for Redox Reactions and Solar Fuel Production. Angewandte Chemie International Edition, 55(18), 5414-5445. doi:10.1002/anie.201505581Shen, L., Liang, R., & Wu, L. (2015). Strategies for engineering metal-organic frameworks as efficient photocatalysts. Chinese Journal of Catalysis, 36(12), 2071-2088. doi:10.1016/s1872-2067(15)60984-6Shi, Y., Yang, A.-F., Cao, C.-S., & Zhao, B. (2019). Applications of MOFs: Recent advances in photocatalytic hydrogen production from water. Coordination Chemistry Reviews, 390, 50-75. doi:10.1016/j.ccr.2019.03.012Wang, S., & Wang, X. (2015). Multifunctional Metal-Organic Frameworks for Photocatalysis. Small, 11(26), 3097-3112. doi:10.1002/smll.201500084Wen, M., Mori, K., Kuwahara, Y., An, T., & Yamashita, H. (2018). Design of Single-Site Photocatalysts by Using Metal-Organic Frameworks as a Matrix. Chemistry - An Asian Journal, 13(14), 1767-1779. doi:10.1002/asia.201800444Das, S., & Wan Daud, W. M. A. (2014). RETRACTED: Photocatalytic CO2 transformation into fuel: A review on advances in photocatalyst and photoreactor. Renewable and Sustainable Energy Reviews, 39, 765-805. doi:10.1016/j.rser.2014.07.046Claessens, C. G., González-Rodríguez, D., & Torres, T. (2002). Subphthalocyanines:  Singular Nonplanar Aromatic CompoundsSynthesis, Reactivity, and Physical Properties. Chemical Reviews, 102(3), 835-854. doi:10.1021/cr0101454N. Kobayashi , in The Porphyrin Handbook , ed. K. M. Kadish , K. M. Smith and R. Guilard , Academic Press , Amsterdam , 2003 , pp. 161–262Santiago-Portillo, A., Baldoví, H. G., Carbonell, E., Navalón, S., Álvaro, M., García, H., & Ferrer, B. (2018). Ruthenium(II) Tris(2,2′-bipyridyl) Complex Incorporated in UiO-67 as Photoredox Catalyst. The Journal of Physical Chemistry C, 122(51), 29190-29199. doi:10.1021/acs.jpcc.8b07204Ferey, G. (2005). A Chromium Terephthalate-Based Solid with Unusually Large Pore Volumes and Surface Area. Science, 309(5743), 2040-2042. doi:10.1126/science.1116275Santiago-Portillo, A., Blandez, J. F., Navalón, S., Álvaro, M., & García, H. (2017). Influence of the organic linker substituent on the catalytic activity of MIL-101(Cr) for the oxidative coupling of benzylamines to imines. Catalysis Science & Technology, 7(6), 1351-1362. doi:10.1039/c6cy02577cSantiago-Portillo, A., Navalón, S., Concepción, P., Álvaro, M., & García, H. (2017). Influence of Terephthalic Acid Substituents on the Catalytic Activity of MIL-101(Cr) in Three Lewis Acid Catalyzed Reactions. ChemCatChem, 9(13), 2506-2511. doi:10.1002/cctc.201700236Claessens, C. G., González-Rodríguez, D., Rodríguez-Morgade, M. S., Medina, A., & Torres, T. (2013). Subphthalocyanines, Subporphyrazines, and Subporphyrins: Singular Nonplanar Aromatic Systems. Chemical Reviews, 114(4), 2192-2277. doi:10.1021/cr400088wGuilleme, J., Martínez-Fernández, L., González-Rodríguez, D., Corral, I., Yáñez, M., & Torres, T. (2014). An Insight into the Mechanism of the Axial Ligand Exchange Reaction in Boron Subphthalocyanine Macrocycles. Journal of the American Chemical Society, 136(40), 14289-14298. doi:10.1021/ja508181bManaga, M., Mack, J., Gonzalez-Lucas, D., Remiro-Buenamañana, S., Tshangana, C., Cammidge, A. N., & Nyokong, T. (2016). Photophysical properties of tetraphenylporphyrinsubphthalocyanine conjugates. Journal of Porphyrins and Phthalocyanines, 20(01n04), 1-20. doi:10.1142/s1088424615500959Bressan, G., Cammidge, A. N., Jones, G. A., Heisler, I. A., Gonzalez-Lucas, D., Remiro-Buenamañana, S., & Meech, S. R. (2019). Electronic Energy Transfer in a Subphthalocyanine–Zn Porphyrin Dimer Studied by Linear and Nonlinear Ultrafast Spectroscopy. The Journal of Physical Chemistry A, 123(27), 5724-5733. doi:10.1021/acs.jpca.9b04398Morse, G. E., & Bender, T. P. (2012). Boron Subphthalocyanines as Organic Electronic Materials. ACS Applied Materials & Interfaces, 4(10), 5055-5068. doi:10.1021/am3015197Sampson, K. L., Jiang, X., Bukuroshi, E., Dovijarski, A., Raboui, H., Bender, T. P., & Kadish, K. M. (2018). A Comprehensive Scope of Peripheral and Axial Substituent Effect on the Spectroelectrochemistry of Boron Subphthalocyanines. The Journal of Physical Chemistry A, 122(18), 4414-4424. doi:10.1021/acs.jpca.8b02023Claessens, C. G., González-Rodríguez, D., del Rey, B., Torres, T., Mark, G., Schuchmann, H.-P., … Nohr, R. S. (2003). Highly Efficient Synthesis of Chloro- and Phenoxy-Substituted Subphthalocyanines. European Journal of Organic Chemistry, 2003(14), 2547-2551. doi:10.1002/ejoc.200300169Speckmeier, E., Fuchs, P. J. W., & Zeitler, K. (2018). A synergistic LUMO lowering strategy using Lewis acid catalysis in water to enable photoredox catalytic, functionalizing C–C cross-coupling of styrenes. Chemical Science, 9(35), 7096-7103. doi:10.1039/c8sc02106

Generating and optimizing the catalytic activity in UiO-66 for aerobic oxidation of alkenes by post-synthetic exchange Ti atoms combined with ligand substitution

[EN] The catalytic activity for the aerobic epoxidation of cyclooctene of UiO-66 has been introduced by post synthetic ion exchange of Zr4+ by Ti4+ at the nodes and the performance optimized by nitro substitution in the terephthalate ligand. In this way a TON value of 16,600 (1660 considering Zr + Ti content) was achieved, comparing favorably with the highest catalytic activity reported in homogeneous for the same reaction (10,000 for gamma-SiW10{(Fe3+(OH2)}(O-38(6-)). Kinetic studies have shown that the most likely reactive oxygen species involved in the oxidation is superoxide, with hydroxyl radicals also contributing to the reaction. UiO-66(Zr-5.4 Ti-0.6)-NO2 is stable under catalytic conditions, being used six times without any change in the conversion temporal profile and in the X-ray diffractogram. The scope of UiO-66(Zr-5.4 Ti-0.6)-NO2 promoted aerobic oxidation of alkenes was expanded by including smaller rings cycloalkenes, as well as acyclic and aryl conjugated alkenes. (C) 2018 Elsevier Inc. All rights reserved.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa and CTQ2014-53292-R and CTQ2015-69563-CO2-14) is gratefully acknowledged. Generalidad Valenciana is also thanked for funding (Prometeo 2017/018). SN thanks financial support by the Fundacion Ramon Areces (XVIII Concurso Nacional para la Adjudicacion de Ayudas a la Investigacion en Ciencias de la Vida y de la Materia, 2016).Santiago-Portillo, A.; Navalón Oltra, S.; Alvaro Rodríguez, MM.; García Gómez, H. (2018). Generating and optimizing the catalytic activity in UiO-66 for aerobic oxidation of alkenes by post-synthetic exchange Ti atoms combined with ligand substitution. Journal of Catalysis. 365:450-463. https://doi.org/10.1016/j.jcat.2018.07.032S45046336

Tuning the Microenvironment of Gold Nanoparticles Encapsulated within MIL-101(Cr) for the Selective Oxidation of Alcohols with O-2: Influence of the Amino Terephthalate Linker

This is the peer reviewed version of the following article: Chem. Eur. J. 2019, 25, 9280 9286, which has been published in final form at https://doi.org/10.1002/chem.201901361. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] This manuscript reports a comparative study of the catalytic performance of gold nanoparticles (NPs) encapsulated within MIL-101(Cr) with or without amino groups in the terephthalate linker. The purpose is to show how the amino groups can influence the microenvironment and catalytic stability of incorporated gold nanoparticles. The first influence of the presence of this substituent is the smaller particle size of Au NPs hosted in MIL-101(Cr)-NH2 (2.45 +/- 0.19 nm) compared with the parent MIL-101(Cr)-H (3.02 +/- 0.39 nm). Both materials are highly active to promote the aerobic alcohol oxidation and exhibit a wide substrate scope. Although both catalysts can achieve turnover numbers as high as 10(6) for the solvent-free aerobic oxidation of benzyl alcohol, Au@MIL-101(Cr)-NH2 exhibits higher turnover frequency values (12 000 h(-1)) than Au@MIL-101(Cr)-H (6800 h(-1)). Au@MIL-101(Cr)-NH2 also exhibits higher catalytic stability, being recyclable for 20 times with coincident temporal conversion profiles, in comparison with some decay observed in the parent Au@MIL-101(Cr)-H. Characterization by transmission electron microscopy of the 20-times used samples shows a very minor particle size increase in the case of Au@MIL-101(Cr)-NH2 (2.97 +/- 0.27 nm) in comparison with the Au@MIL-101(Cr)-H analog (5.32 +/- 0.72 nm). The data presented show the potential of better control of the microenvironment to improve the performance of encapsulated Au nanoparticles.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa, CTQ2015-65963-CQ-R1 and CTQ2014-53292-R) is gratefully acknowledged. Generalidad Valenciana is also thanked for funding (Prometeo 2017/083). S.N. thanks financial support by the Fundacijn Ramjn Areces (XVIII Concurso Nacional para la Adjudicacijn de Ayudas a la Investigacijn en Ciencias de la Vida y de la Materia, 2016).Santiago-Portillo, A.; Cabrero-Antonino, M.; Alvaro Rodríguez, MM.; Navalón Oltra, S.; García Gómez, H. (2019). Tuning the Microenvironment of Gold Nanoparticles Encapsulated within MIL-101(Cr) for the Selective Oxidation of Alcohols with O-2: Influence of the Amino Terephthalate Linker. Chemistry - A European Journal. 25(39):9280-9286. https://doi.org/10.1002/chem.201901361S928092862539H�ft, E., Kosslick, H., Fricke, R., & Hamann, H.-J. (1996). Titanhaltige Molekularsiebe als Katalysatoren f�r selektive Oxidationsreaktionen mit Wasserstoffperoxid. Journal f�r Praktische Chemie/Chemiker-Zeitung, 338(1), 1-15. doi:10.1002/prac.19963380102Matsumoto, T., Ueno, M., Wang, N., & Kobayashi, S. (2008). Recent Advances in Immobilized Metal Catalysts for Environmentally Benign Oxidation of Alcohols. Chemistry - An Asian Journal, 3(2), 196-214. doi:10.1002/asia.200700359Saikia, M., Bhuyan, D., & Saikia, L. (2015). Facile synthesis of Fe3O4nanoparticles on metal organic framework MIL-101(Cr): characterization and catalytic activity. New Journal of Chemistry, 39(1), 64-67. doi:10.1039/c4nj01312cCorma, A., & Garcia, H. (2008). Supported gold nanoparticles as catalysts for organic reactions. Chemical Society Reviews, 37(9), 2096. doi:10.1039/b707314nParmeggiani, C., & Cardona, F. (2012). Transition metal based catalysts in the aerobic oxidation of alcohols. Green Chemistry, 14(3), 547. doi:10.1039/c2gc16344fStahl, S. S. (2004). Palladium Oxidase Catalysis: Selective Oxidation of Organic Chemicals by Direct Dioxygen-Coupled Turnover. Angewandte Chemie International Edition, 43(26), 3400-3420. doi:10.1002/anie.200300630Dhakshinamoorthy, A., & Garcia, H. (2012). Catalysis by metal nanoparticles embedded on metal–organic frameworks. Chemical Society Reviews, 41(15), 5262. doi:10.1039/c2cs35047eAlhumaimess, M., Lin, Z., He, Q., Lu, L., Dimitratos, N., Dummer, N. F., … Hutchings, G. J. (2014). Oxidation of Benzyl Alcohol and Carbon Monoxide Using Gold Nanoparticles Supported on MnO2Nanowire Microspheres. Chemistry - A European Journal, 20(6), 1701-1710. doi:10.1002/chem.201303355Buonerba, A., Cuomo, C., Ortega Sánchez, S., Canton, P., & Grassi, A. (2011). Gold Nanoparticles Incarcerated in Nanoporous Syndiotactic Polystyrene Matrices as New and Efficient Catalysts for Alcohol Oxidations. Chemistry - A European Journal, 18(2), 709-715. doi:10.1002/chem.201101034Costa, V. V., Estrada, M., Demidova, Y., Prosvirin, I., Kriventsov, V., Cotta, R. F., … Gusevskaya, E. V. (2012). Gold nanoparticles supported on magnesium oxide as catalysts for the aerobic oxidation of alcohols under alkali-free conditions. Journal of Catalysis, 292, 148-156. doi:10.1016/j.jcat.2012.05.009Zhang, W., Xiao, Z., Wang, J., Fu, W., Tan, R., & Yin, D. (2019). Selective Aerobic Oxidation of Alcohols over Gold‐Palladium Alloy Catalysts Using Air at Atmospheric Pressure in Water. ChemCatChem, 11(6), 1779-1788. doi:10.1002/cctc.201900015Liu, X. Y., Wang, A., Zhang, T., & Mou, C.-Y. (2013). Catalysis by gold: New insights into the support effect. Nano Today, 8(4), 403-416. doi:10.1016/j.nantod.2013.07.005Navalon, S., Dhakshinamoorthy, A., Alvaro, M., & Garcia, H. (2016). Metal nanoparticles supported on two-dimensional graphenes as heterogeneous catalysts. Coordination Chemistry Reviews, 312, 99-148. doi:10.1016/j.ccr.2015.12.005Dhakshinamoorthy, A., Asiri, A. M., & Garcia, H. (2017). Metal Organic Frameworks as Versatile Hosts of Au Nanoparticles in Heterogeneous Catalysis. ACS Catalysis, 7(4), 2896-2919. doi:10.1021/acscatal.6b03386Howarth, A. J., Liu, Y., Li, P., Li, Z., Wang, T. C., Hupp, J. T., & Farha, O. K. (2016). Chemical, thermal and mechanical stabilities of metal–organic frameworks. Nature Reviews Materials, 1(3). doi:10.1038/natrevmats.2015.18Lee, J., Farha, O. K., Roberts, J., Scheidt, K. A., Nguyen, S. T., & Hupp, J. T. (2009). Metal–organic framework materials as catalysts. Chemical Society Reviews, 38(5), 1450. doi:10.1039/b807080fLeus, K., Concepcion, P., Vandichel, M., Meledina, M., Grirrane, A., Esquivel, D., … Van Der Voort, P. (2015). Au@UiO-66: a base free oxidation catalyst. RSC Advances, 5(29), 22334-22342. doi:10.1039/c4ra16800cSaikia, M., Kaichev, V., & Saikia, L. (2016). Gold nanoparticles supported on nanoscale amine-functionalized MIL-101(Cr) as a highly active catalyst for epoxidation of styrene. RSC Advances, 6(108), 106856-106865. doi:10.1039/c6ra24458kLiu, H., Liu, Y., Li, Y., Tang, Z., & Jiang, H. (2010). Metal−Organic Framework Supported Gold Nanoparticles as a Highly Active Heterogeneous Catalyst for Aerobic Oxidation of Alcohols. The Journal of Physical Chemistry C, 114(31), 13362-13369. doi:10.1021/jp105666fLammert, M., Bernt, S., Vermoortele, F., De Vos, D. E., & Stock, N. (2013). Single- and Mixed-Linker Cr-MIL-101 Derivatives: A High-Throughput Investigation. Inorganic Chemistry, 52(15), 8521-8528. doi:10.1021/ic4005328Zhu, Q.-L., Li, J., & Xu, Q. (2013). Immobilizing Metal Nanoparticles to Metal–Organic Frameworks with Size and Location Control for Optimizing Catalytic Performance. Journal of the American Chemical Society, 135(28), 10210-10213. doi:10.1021/ja403330mChen, Y. F., Babarao, R., Sandler, S. I., & Jiang, J. W. (2010). Metal−Organic Framework MIL-101 for Adsorption and Effect of Terminal Water Molecules: From Quantum Mechanics to Molecular Simulation. Langmuir, 26(11), 8743-8750. doi:10.1021/la904502hFerey, G. (2005). A Chromium Terephthalate-Based Solid with Unusually Large Pore Volumes and Surface Area. Science, 309(5743), 2040-2042. doi:10.1126/science.1116275Santiago-Portillo, A., Navalón, S., Cirujano, F. G., Xamena, F. X. L. i, Alvaro, M., & Garcia, H. (2015). MIL-101 as Reusable Solid Catalyst for Autoxidation of Benzylic Hydrocarbons in the Absence of Additional Oxidizing Reagents. ACS Catalysis, 5(6), 3216-3224. doi:10.1021/acscatal.5b00411Buxton, G. V., Greenstock, C. L., Helman, W. P., & Ross, A. B. (1988). Critical Review of rate constants for reactions of hydrated electrons, hydrogen atoms and hydroxyl radicals (⋅OH/⋅O− in Aqueous Solution. Journal of Physical and Chemical Reference Data, 17(2), 513-886. doi:10.1063/1.555805Clifton, C. L., & Huie, R. E. (1989). Rate constants for hydrogen abstraction reactions of the sulfate radical, SO4?. Alcohols. International Journal of Chemical Kinetics, 21(8), 677-687. doi:10.1002/kin.550210807Dhakshinamoorthy, A., Asiri, A. M., & Garcia, H. (2017). Tuneable nature of metal organic frameworks as heterogeneous solid catalysts for alcohol oxidation. Chemical Communications, 53(79), 10851-10869. doi:10.1039/c7cc05927bCancino, P., Vega, A., Santiago-Portillo, A., Navalon, S., Alvaro, M., Aguirre, P., … García, H. (2016). A novel copper(ii)–lanthanum(iii) metal organic framework as a selective catalyst for the aerobic oxidation of benzylic hydrocarbons and cycloalkenes. Catalysis Science & Technology, 6(11), 3727-3736. doi:10.1039/c5cy01448dGómez-Paricio, A., Santiago-Portillo, A., Navalón, S., Concepción, P., Alvaro, M., & Garcia, H. (2016). MIL-101 promotes the efficient aerobic oxidative desulfurization of dibenzothiophenes. Green Chemistry, 18(2), 508-515. doi:10.1039/c5gc00862

MIL-101(Cr)-NO2 as efficient catalyst for the aerobic oxidation of thiophenols and the oxidative desulfurization of dibenzothiophenes

[EN] A series of MIL-101(Cr)-X functionalized with electron withdrawing (NO2, SO3H or Cl) or electron donor (NH2 or CH3) groups has been tested for the solvent-free oxidative coupling of thiophenol to disulfides. No byproducts were observed. A relationship between the catalytic activity of these MOFs with the substituent meta Hammet constant on the terephthalate ligand and with their redox potential was found, MIL-101(Cr)-NO2 being the most active catalyst. NO2-substituted MIL-101 is also more efficient than the parent MIL-101(Cr) to promote the aerobic desulfurization of dibenzothiophenes in n-dodecane or commercial Diesel as solvent. No byproduct formation was observed. Mechanistic studies reveal that MIL-101(Cr)-NO2 is acting as heterogeneous catalyst in thiophenol oxidation and as radical initiator for the aerobic desulfurization. For both reactions, the catalyst can be reused without deactivation, maintaining its crystallinity and with negligible metal leaching.Financial support by the Spanish Ministry of Science and Innovation (Severo Ochoa and RTI2018-098237-CO21) and Generalitat Valenciana (Prometeo 2017/083) is gratefully acknowledged. S.N. thanks financial support by the Fundacion Ramon Areces (XVIII Concurso Nacional para la Adjudicacion de Ayudas a la Investigacion en Ciencias de la Vida y de la Materia, 2016), Ministerio de Ciencia, Innovacion y Universidades CTQ-2018 RTI2018-099482-A-I00 project and Generalitat Valenciana grupos de investigacion consolidables 2019 (AICO2019/214 project).Vallés-García, C.; Santiago-Portillo, A.; Alvaro Rodríguez, MM.; Navalón Oltra, S.; García Gómez, H. (2020). MIL-101(Cr)-NO2 as efficient catalyst for the aerobic oxidation of thiophenols and the oxidative desulfurization of dibenzothiophenes. Applied Catalysis A General. 590:1-8. https://doi.org/10.1016/j.apcata.2019.117340S18590Férey, G., Mellot-Draznieks, C., Serre, C., Millange, F., Dutour, J., Surblé, S., & Margiolaki, I. (2005). A Chromium Terephthalate-Based Solid with Unusually Large Pore Volumes and Surface Area. Science, 309(5743), 2040-2042. doi:10.1126/science.1116275Furukawa, H., Cordova, K. E., O’Keeffe, M., & Yaghi, O. M. (2013). The Chemistry and Applications of Metal-Organic Frameworks. Science, 341(6149). doi:10.1126/science.1230444Eddaoudi, M., Kim, J., Rosi, N., Vodak, D., Wachter, J., O’Keeffe, M., & Yaghi, O. M. (2002). Systematic Design of Pore Size and Functionality in Isoreticular MOFs and Their Application in Methane Storage. Science, 295(5554), 469-472. doi:10.1126/science.1067208Kitagawa, S., Kitaura, R., & Noro, S. (2004). Functional Porous Coordination Polymers. Angewandte Chemie International Edition, 43(18), 2334-2375. doi:10.1002/anie.200300610Yaghi, O. M., O’Keeffe, M., Ockwig, N. 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Influence of the organic linker substituent on the catalytic activity of MIL-101(Cr) for the oxidative coupling of benzylamines to imines

[EN] MIL-101(Cr) having substituents at the terephthalate linker (X = H, NO2, SO3H, Cl, CH3 and NH2) promotes the aerobic oxidation of benzylamines to the corresponding N-benzylidene benzylamines at different rates. MIL-101(Cr)¿NO2 was the most active catalyst, about 6-fold more active than the parent MIL-101(Cr). MIL-101(Cr)¿NO2 does not deactivate significantly upon five consecutive reuses, does not leach the metal to the solution and maintains its crystallinity. MIL-101(Cr)¿NO2 is active for a wide range of benzylamines including para-substituted, heterocyclic benzylamines and di- and tribenzylamines.Financial support by the Spanish Ministry of Economy and Competitiveness (CTQ 2015-69153-CO2-1, CTQ2014-53292-R, Severo Ochoa) and Generalitat Valenciana (Prometeo 2013014) is gratefully acknowledged.Santiago-Portillo, A.; Blandez, JF.; Navalón Oltra, S.; Alvaro Rodríguez, MM.; García Gómez, H. (2017). Influence of the organic linker substituent on the catalytic activity of MIL-101(Cr) for the oxidative coupling of benzylamines to imines. Catalysis Science & Technology. 7(6):1351-1362. https://doi.org/10.1039/c6cy02577cS135113627

Aqueous Phase Methanol Reforming Catalyzed by Fe-Cu Alloy Nanoparticles Wrapped on Nitrogen-Doped Graphene

[EN] Small Fe-Cu nanoparticles (NPs) (about 1 nm) supported at a high loading (over 10 wt %) on N-doped graphitic carbon have been prepared in a single pyrolytic step from chitosan adsorbing Cu2+ and Fe2+ salts. The presence of N atoms appears to be crucial in the formation of small-sized metallic NPs. Interactions between Fe and Cu are reflected by a shift in the binding energy to higher (Fe) or lower (Cu) values and by H-2 thermo-programmed reduction measurements, showing a new reduction peak at intermediate temperature (375 degrees C) between that of Cu (175 degrees C) and that of Fe (450 degrees C). Fe-Cu NPs embedded within the N-doped graphitic carbon matrix are extremely active (TOF 315 h(-1)) and selective (no CO detected) catalysts for methanol reforming in the aqueous phase with stoichiometric H2O amounts to H-2 and CO2. The results achieved with Fe-Cu compare favorably with those reported in the literature for catalysts based on Pt, Pd, or Ru.Financial support by the Spanish Ministry of Innovation and Science (Severo Ochoa and RTI2018-89237-CO2-1) and Generalitat Valenciana (Prometeo 2021-083) is gratefully acknowledged.García-Baldoví, A.; Peng, L.; Santiago-Portillo, A.; Asiri, AM.; Primo Arnau, AM.; García Gómez, H. (2022). Aqueous Phase Methanol Reforming Catalyzed by Fe-Cu Alloy Nanoparticles Wrapped on Nitrogen-Doped Graphene. ACS Applied Energy Materials. 5(7):9173-9180. https://doi.org/10.1021/acsaem.2c01806917391805

Long-Term Photostability in Terephthalate Metal-Organic Frameworks

This is the peer reviewed version of the following article: Mateo, Diego, et al. Long-Term Photostability in Terephthalate Metal-Organic Frameworks. Angewandte Chemie (International Ed.), vol. 58, no. 49, Wiley, 2019, pp. 17843 48, doi:10.1002/anie.201911600, which has been published in final form at https://doi.org/10. 1002/anie.201911600. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] Prolonged (weeks) UV/Vis irradiation under Ar of UiO-66(Zr), UiO66 Zr-NO2, MIL101 Fe, MIL125 Ti-NH2, MIL101 Cr and MIL101 Cr(Pt) shows that these MOFs undergo photodecarboxylation of benzenedicarboxylate (BDC) linker in a significant percentage depending on the structure and composition of the material. Routine characterization techniques such as XRD, UV/Vis spectroscopy and TGA fail to detect changes in the material, although porosity and surface area change upon irradiation of powders. In contrast to BCD-containing MOFs, zeolitic imidazolate ZIF-8 does not evolve CO2 or any other gas upon irradiation.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa, and CTQ2015-69563-CO2-R1) and by the Generalitat Valenciana (Prometeo 2013-014) is gratefully acknowledged. J.A. thanks the Universitat Politecnica de Valencia for a postdoctoral scholarship. D.M. also thanks Spanish Ministry of Science for PhD Scholarship.Mateo-Mateo, D.; Santiago-Portillo, A.; Albero-Sancho, J.; Navalón Oltra, S.; Alvaro Rodríguez, MM.; García Gómez, H. (2019). Long-Term Photostability in Terephthalate Metal-Organic Frameworks. Angewandte Chemie International Edition. 58(49):17843-17848. https://doi.org/10.1002/anie.201911600S1784317848584

MIL-101 promotes the efficient aerobic oxidative desulfurization of dibenzothiophenes

[EN] MIL-101 promotes aerobic oxidation in n-dodecane of dibenzothiophene (DBT) and its methyl-substituted derivatives to their corresponding sulfones with complete selectivity, without observation of the sulfoxide. DBT sulfones can be completely separated from n-dodecane by water extraction. MIL-101(Cr) without the need of pre-activation was found to be more convenient than the also-active MIL-101(Fe) analog. The reaction exhibits an induction period due to the diffusion inside the pore system of the solvent or oxygen and it is not observed if the MIL-101 sample is first in contact with the solvent at the reaction temperature for a sufficiently long time. MIL-101 is reusable for at least five times without any sign of deactivation according to the time-conversion plots. Evidence by electron paramagnetic resonance spectroscopy detecting the hydroperoxide radical adduct with a spin trapping agent and Raman spectroscopy detection of superoxide supports that the process is an auto-oxidation reaction initiated by MIL-101 following the expected radical chain mechanism inside the MIL-101 cages.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa and CTQ2012-32315) is gratefully acknowledged. Generalidad Valenciana is also thanked for funding (Prometeo 2012/013 and GV/2013/040).Gómez Paricio, A.; Santiago Portillo, A.; Navalón Oltra, S.; Concepción Heydorn, P.; Alvaro Rodríguez, MM.; García Gómez, H. (2016). MIL-101 promotes the efficient aerobic oxidative desulfurization of dibenzothiophenes. Green Chemistry. 18(2):508-515. doi:10.1039/C5GC00862JS50851518

Room temperature silylation of alcohols catalyzed by metal organic frameworks

[EN] The commercial Al(OH)(BDC) (BDC: 1,4-benzenedicarboxylic acid) metal organic framework (Basolite A100) is a suitable heterogeneous catalyst for the silylation of benzylic and aliphatic alcohols by hexamethyldisilazane in toluene at room temperature. Al(OH)(BDC) is stable under the reaction conditions as evidenced by powder XRD and can be reused with minimal activity decrease.AD thanks University Grants Commission (UGC), New Delhi for the award of Assistant Professorship under its Faculty Recharge Programme. AD also thanks the Department of Science and Technology, India for the financial support through the Fast Track project (SB/FT/CS-166/2013) and the Generalidad Valenciana for financial aid supporting his stay in Valencia through the Prometeo programme. Financial support by the Spanish Ministry of Economy and Competitiveness (CTQ-2015-69 153-CO2-R1 and Severo Ochoa) and Generalidad Valenciana (Prometeo 2012-014) is gratefully acknowledgedDhakshinamoorthy, A.; Santiago-Portillo, A.; Concepción Heydorn, P.; Herance, JR.; Navalón Oltra, S.; Alvaro Rodríguez, MM.; García Gómez, H. (2017). Room temperature silylation of alcohols catalyzed by metal organic frameworks. Catalysis Science & Technology. 7(12):2445-2449. https://doi.org/10.1039/c7cy00834aS24452449712T. W. Greene and P. G. M.Wuts, Protective Groups in Organic Synthesis, Wiley & Sons, New York, 3rd edn, 1999, p. 116Sartori, G., Ballini, R., Bigi, F., Bosica, G., Maggi, R., & Righi, P. (2004). Protection (and Deprotection) of Functional Groups in Organic Synthesis by Heterogeneous Catalysis. Chemical Reviews, 104(1), 199-250. doi:10.1021/cr0200769Corey, E. J., & Snider, B. B. (1972). Total synthesis of (+-)-fumagillin. 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Nanocrystalline TiO2–HClO4 as a new, efficient and recyclable catalyst for the chemoselective trimethylsilylation of alcohols, phenols and deprotection of silyl ethers. Catalysis Communications, 18, 5-10. doi:10.1016/j.catcom.2011.11.002Sridhar, M., Raveendra, J., China Ramanaiah, B., & Narsaiah, C. (2011). An efficient synthesis of silyl ethers of primary alcohols, secondary alcohols, phenols and oximes with a hydrosilane using InBr3 as a catalyst. Tetrahedron Letters, 52(45), 5980-5982. doi:10.1016/j.tetlet.2011.08.151Shirini, F., Khaligh, N. G., & Akbari-Dadamahaleh, S. (2012). Preparation, characterization and use of 1,3-disulfonic acid imidazolium hydrogen sulfate as an efficient, halogen-free and reusable ionic liquid catalyst for the trimethylsilyl protection of hydroxyl groups and deprotection of the obtained trimethylsilanes. Journal of Molecular Catalysis A: Chemical, 365, 15-23. doi:10.1016/j.molcata.2012.08.002Villabrille, P., Romanelli, G., Quaranta, N., & Vázquez, P. (2010). An efficient catalytic route for the preparation of silyl ethers using alumina-supported heteropolyoxometalates. Applied Catalysis B: Environmental, 96(3-4), 379-386. doi:10.1016/j.apcatb.2010.02.035Shirini, F., & Mollarazi, E. (2007). Efficient trimethylsilylation of alcohols and phenols in the presence of ZrCl4 as a reusable catalyst. Catalysis Communications, 8(9), 1393-1396. doi:10.1016/j.catcom.2006.11.015Chughtai, A. H., Ahmad, N., Younus, H. A., Laypkov, A., & Verpoort, F. (2015). Metal–organic frameworks: versatile heterogeneous catalysts for efficient catalytic organic transformations. Chemical Society Reviews, 44(19), 6804-6849. doi:10.1039/c4cs00395kLiu, J., Chen, L., Cui, H., Zhang, J., Zhang, L., & Su, C.-Y. (2014). Applications of metal–organic frameworks in heterogeneous supramolecular catalysis. Chem. Soc. Rev., 43(16), 6011-6061. doi:10.1039/c4cs00094cDhakshinamoorthy, A., Asiri, A. M., & Garcia, H. (2015). 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Metal organic frameworks as heterogeneous catalysts for the selective N-methylation of aromatic primary amines with dimethyl carbonate. Applied Catalysis A: General, 378(1), 19-25. doi:10.1016/j.apcata.2010.01.042Boutin, A., Springuel-Huet, M.-A., Nossov, A., Gédéon, A., Loiseau, T., Volkringer, C., … Fuchs, A. H. (2009). Breathing Transitions in MIL-53(Al) Metal-Organic Framework Upon Xenon Adsorption. Angewandte Chemie International Edition, 48(44), 8314-8317. doi:10.1002/anie.200903153Sholl, D. S., & Lively, R. P. (2015). Defects in Metal–Organic Frameworks: Challenge or Opportunity? The Journal of Physical Chemistry Letters, 6(17), 3437-3444. doi:10.1021/acs.jpclett.5b01135Fang, Z., Bueken, B., De Vos, D. E., & Fischer, R. A. (2015). Defect-Engineered Metal-Organic Frameworks. Angewandte Chemie International Edition, 54(25), 7234-7254. doi:10.1002/anie.20141154