Síntesis de nuevos materiales magnéticos multifuncionales con ligandos aromáticos polioxamato

The main goal of this Ph.D thesis concerns the synthesis of multifunctional magnetic coordination polymers with oxamato ligands, which is one of the most challenging topics for chemists and physicists working together in the multidisciplinary field of materials chemistry. In order to do so, we have taken advantage of the new developments of metallosupramolecular chemistry, in particular the molecular-programmed self-assembly methods that exploit the coordination preferences of metal ions and specifically tailored ligands. In this sense, the judicious choice of the appropriate oxamato-based metal building block (substitution pattern and steric requirements of the bridging ligand, as well as the electronic configuration and magnetic anisotropy of the metal ion) allowed us to control the different structural topologies as well as the interesting and predictable magnetic properties in the final compounds. Interestingly, most of the synthesized coordination polymers are anionic. Thus, we can, tentatively, insert an additional physical property (to the magnetic ones) by using the appropriate countercation. The results obtained along this Ph.D thesis are divided in three different chapters according to the dimensionality of the coordination polymer. Furthermore, each chapter is subdivided in two parts (A and B) depending on the properties exhibited by the compounds (Chapter I) and the nature of the precursor used to synthesized the coordination polymers (Chapters II and III). Chapter I has been divided in two parts in accordance with the properties of the one-dimensional compounds. Thus, in the first part we present the synthesis of a new family of neutral oxamato-bridged heterobimetallic chains MIICuII (M = Mn and Co) prepared by treating the corresponding anionic oxamatocopper(II) complexes with 3d cations using DMF or DMSO as solvents. Interestingly, this family of heterobimetallic chains provides several examples of Single Chain Magnets (SCMs), where the nature of the corresponding transition metal as well as the substitution pattern of the bridging ligand on the SCM behaviour were studied. In the second part of this chapter we prepared a new series of neutral oxamato-bridged heterobimetallic chiral chains MIICuII (M = Mn and Co), where only the enantiopure CoIICuII chains showed slow magnetic relaxation at low temperatures, which is characteristic of SCMs. Furthermore, solid circular dichroism (CD) spectra of the bimetallic chain compounds were recorded in order to establish their chiral and enantiomeric nature. As each couple of enantiomeric chains are non superimposable mirror images, they exhibit maximum positive and negative Cotton effects, constituting the first examples of enantiopure SCMs. In the second chapter, we present several two- (2D) and three-dimensional (3D) coordination polymers exhibiting different architectures and magnetic properties, that can somehow be controlled by means of the appropriate choice of the precursor and the metal ion used to build them. Furthermore, we present for the first time in oxamato-based compounds the porous properties of some of them. At this respect, in the first part of this chapter we explain the influence of the metal ions and the monooxamatocopper(II) complexes on the topology and the magnetic properties of the synthesized coordination polymers. In the second part we describe a family of heterobimetallic MIICuII (M = Mn and Co) bidimensional coordination polymers obtained by reaction of the corresponding dinuclear bis-oxamatocopper(II) complexes with the metal ions. Additionally, in this family we studied the influence of the substitution pattern of the bridging ligand on the magnetic properties. The last chapter is devoted to the introduction of multifunctionality in oxamato-based systems. It has been divided again in two parts in accordance with the nature of the precursor used to synthesize the multifunctional coordination polymer. Anyway both parts have a common background consisting on the use of the complex as ligand strategy in order to build the anionic inorganic network, the other physical property being brought by the organic countercation. At this respect, in the first part we focus on the use the monooxamatocopper(II) precursor complexes with different functional countercations, which added the new property, toward manganese(II) ions to obtain the corresponding bi- and tridimensional compounds that encapsulate the non-innocent counteractions. Similarly, in the second part we describe the synthesis of the same kind of multifunctional 2D and 3D polymers by using dinuclear oxamato-copper(II) precursors instead of the mononuclear ones. For example, herein we report the first oxamato-based examples of: (i) chiral magnets, (ii) luminescent magnets, (iii) porous magnets showing sorption properties and (iv) a porous magnet showing a solvatomagnetic switching

Crystallographic Visualization of a Double Water Molecule Addition on a Pt-1-MOF during the Low-temperature Water-Gas Shift Reaction

This is the peer reviewed version of the following article: C. Bilanin, E. Tiburcio, J. Ferrando-Soria, D. Armentano, A. Leyva-Pérez, E. Pardo, ChemCatChem 2021, 13, 1195, which has been published in final form at https://doi.org/10.1002/cctc.202001492. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] The low-temperature water-gas shift reaction (WGSR, CO+H2O H-2+CO2) is considered a very promising reaction -candidate for fuel cells- despite an efficient and robust catalyst is still desirable. One of the more prominent catalysts for this reaction is based on single Pt atoms (Pt-1) on different supports, which are supposed to manifold the reaction by the accepted mechanism for the general WGSR, i. e. by addition of one H2O molecule to CO, with generation of CO2 and H-2. Here we show, experimentally, that not one but two H2O molecules are added to CO on the Pt-1 catalyst, as assessed by a combination of reactivity experiments with soluble Pt catalysts, kinetic and spectroscopic measurements, and finally by in-operando single crystal X-ray diffraction on a Pt-1-MOF, to visualize the formation of the hemiacetal intermediate on the solid catalytic site. These results confirm our previous DFT predictions and provide a paradigmatic shift in the assumed mechanism of the WGSR, which may open the debate if two H2O molecules are recurrently added during the WGSR, not only for Pt-1 catalysts but also for other metal catalysts.This work was supported by the Ministero dell'Istruzione, dell'Universita e della Ricerca (Italy) and the Ministerio de Ciencia e Innovacion (Spain) (Projects PID2019-104778GB-I00 and CTQ2017-86735-P and the excellence units "Severo Ochoa" SEV-2016-0683 and "Maria de Maeztu" CEX2019-000919-M). C. B. and E. T. thank ITQ and MINECO for the concession of fellowships. Thanks are extended to the "2019 Post-doctoral Junior Leader-Retaining Fellowship, la Caixa Foundation (ID100010434 and fellowship code LCF/BQ/PR19/11700011" (J. F.-S.). D.A. acknowledges the financial support of the Fondazione CARIPLO / "Economia Circolare: ricerca per un futuro sostenibile" 2019, Grant number: 2019-2090, MOCA. We thank to Dr. R. Adam, Dr. J. Oliver-Meseguer and J. C. Arango for their help. E.P. acknowledges the financial support of the European Research Council under the European Union's Horizon 2020 research and innovation programme / ERC Grant Agreement No 814804, MOF-reactors. We acknowledge Diamond Light Source for awarded beamtime and provision of synchrotron radiation facilities with dosing gas cell and thank Dr Mark Warren for his assistance at I19 beamline (Proposal number MT18768-2).Bilanin-Artigado, C.; Tiburcio, E.; Ferrando-Soria, J.; Armentano, D.; Leyva Perez, A.; Pardo, E. (2021). Crystallographic Visualization of a Double Water Molecule Addition on a Pt-1-MOF during the Low-temperature Water-Gas Shift Reaction. ChemCatChem. 13(4):1195-1200. https://doi.org/10.1002/cctc.202001492S1195120013

Magnetic order in a CuII-DyIII oxamato-based two-dimensional coordination polymer

We report the synthesis, crystal structure and magnetic characterization of a novel two-dimensional copper(II)-dysprosium(III) coordination polymer of formula [LiI(OH2)4]2[DyIIICuII2(Me2pma)4Cl(H2O)] . 4H2O (1) [Me2pma = N-2,6-dimethylphenyloxamate]. Compound 1 was obtained by using the mononuclear anionic complex, [CuII(Me2pma)2]2-, as a bis(bidentate) metalloligand toward solvated dysprosium(III) cations and shows a square [DyIIICuII2] layered structure of (44.62) net topology. Interestingly, the combination of two factors, the well-known efficiency of oxamato ligands to transmit strong magnetic couplings between neighboring atoms and such structural topology, is responsible for the observation of a ferromagnetic interaction between copper(II) and dysprosium(III) cations and a magnetic ordering (TC = 7.5 K), paving the way for the obtention of novel future examples of the still very scarce magnetically ordered lanthanide-based coordination polymers

Highly Efficient MOF-Driven Silver Subnanometer Clusters for the Catalytic Buchner Ring Expansion Reaction

[EN] The preparation of novel efficient catalyststhat could be applicable in industrially important chemical processeshas attracted great interest. Small subnanometer metal clusters can exhibit outstanding catalytic capabilities, and thus, research efforts have been devoted, recently, to synthesize novel catalysts bearing such active sites. Here, we report the gram-scale preparation of Ag-2(0) subnanometer clusters within the channels of a highly crystalline three-dimensional anionic metal-organic framework, with the formula [Ag-2(0)]@(Ag2Na2I)-Na-I{Ni-4(II)[Cu-2(II)(Me(3)mpba)(2)](3)}middot48H(2)O [Me(3)mpba(4-) = N,N '-2,4,6-trimethyl-1,3-phenylenebis(oxamate)]. The resulting crystalline solid catalystfully characterized with the help of single-crystal X-ray diffractionexhibits high catalytic activity for the catalytic Buchner ring expansion reaction.This work was supported by the Ministero dell'Universita e della Ricerca (Italy), the MICIIN (Spain) (projects PID2020- 115100GB-I00, PID2019-104778GB-I00 and Excellence Unit "Maria de Maeztu" CEX2019-000919-M) , and the Generalitat Valenciana (project PROMETEO/2021/054). Thanks are also extended to the Ramon y Cajal Program (RYC2019-027940-I) (J. F.-S.) and the Diamond Light Source for the awarded beamtime and provision of synchrotron radiation facilities (proposal no. CY22411-1). We particularly acknowledge Dr David Allan and Sarah Barnett for their assistance at the I19 beamline. E.P. acknowledges the financial support of the European Research Council under the European Union's Horizon 2020 research and innovation programme/ERC grant agreement no 814804, MOF-reactors. M.M. thanks MICIIN from a contract under the Juan de la Cierva program (FJC2019-040523-I). Y.Z. thanks the China Scholarship Council (CSC no: 202009350009) for a Ph.D. fellowship.Tiburcio, E.; Zheng, Y.; Mon-Conejero, M.; Martín, N.; Ferrando-Soria, J.; Armentano, D.; Leyva Perez, A.... (2022). Highly Efficient MOF-Driven Silver Subnanometer Clusters for the Catalytic Buchner Ring Expansion Reaction. Inorganic Chemistry. 61:11796-11802. https://doi.org/10.1021/acs.inorgchem.2c0150811796118026

Glassy PEEK‐WC vs Rubbery Pebax®1657 Polymers: Effect on the Gas Transport in CuNi‐MOF Based Mixed Matrix Membranes

Mixed matrix membranes (MMMs) are seen as promising candidates to overcome the fundamental limit of polymeric membranes, known as the so‐called Robeson upper bound, which defines the best compromise between permeability and selectivity of neat polymeric membranes. To overcome this limit, the permeability of the filler particles in the MMM must be carefully matched with that of the polymer matrix. The present work shows that it is not sufficient to match only the permeability of the polymer and the dispersed phase, but that one should consider also the individual contributions of the diffusivity and the solubility of the gas in both components. Here we compare the gas transport performance of two different MMMs, containing the metal-organic framework CuNi‐MOF in the rubbery Pebax®1657 and in the glassy poly(ether‐ether‐ketone) with cardo moiety, PEEK‐WC. The chemical and structural properties of MMMs were investigated by means of FT‐IR spectroscopy, scanning electron microscopy and EDX analysis. The influence of MOF on the mechanical and thermal properties of both polymers was investigated by tensile tests and differential scanning calorimetry, respectively. The MOF loading in Pebax®1657 increased the ideal H2/N2 selectivity from 6 to 8 thanks to an increased H2 permeability. In general, the MOF had little effect on the Pebax®165 membranes because an increase in gas solubility was neutralized by an equivalent decrease in effective diffusivity. Instead, the addition of MOF to PEEK‐WC increases the ideal CO2/CH4 selectivity from 30 to ~48 thanks to an increased CO2 permeability (from 6 to 48 Barrer). The increase in CO2 permeability and CO2/CH4 selectivity is maintained under mixed gas conditions

Switching of easy-axis to easy-plane anisotropy in cobalt(ii) complexes

A tetranuclear cubane-type complex [Co4(ntfa)4(CH3O)4(CH3OH)4] (1) with a {Co4O4} core, and a mononuclear complex [Co(ntfa)2(CH3OH)2] (2) have been rationally obtained by adjusting the ratio of the β-diketonate and Co(II) ions, with the synthetic processes being monitored by in situ microcalorimetry. Then, following synthetic conditions to obtain 2, but using three distinct N-donor coligands - 2,2'-bipyridyl (bpy), 6,6'-dimethyl-2,2'-bipyridyl (6,6-(CH3)2-bpy) and 5,5'-dimethyl-2,2'-bipyridyl (5,5-(CH3)2-bpy) - three novel mononuclear complexes have been obtained, [Co(ntfa)2(bpy)2] (3), [Co(ntfa)2(6,6-(CH3)2- bpy)2] (4) and [Co(ntfa)2(5,5-(CH3)2-bpy)2] (5). The introduction of different capping coligands - as singlecrystal X-ray crystallography ascertains - fine-tunes the structures, with changes in both the distortion degree of the coordination geometry and the intermolecular interactions, which have a direct impact on the magnetic properties of these complexes. Magnetic investigations reveal field-induced single-ion magnet behavior in all complexes with distinct energy barriers (Ueff) −39.06 (1), 36.65 (2), 36.32 (3), 28.26 (4) and 15.85 K (5). Magnetic experiments together with HF-EPR measurements and theoretical calculations demonstrate that 2 features easy-axis magnetic anisotropy (D = −60.48 cm−1), whereas 3-5 show easy-plane magnetic anisotropies − D = +70.77 cm−1 for 3, +35.71 cm−1 for 4, and +51.28 cm−1 for 5. To our knowledge, such reversal of anisotropic nature driven by coligands is unprecedented

A series of lanthanide(iii) metal-organic frameworks derived from a pyridyl-dicarboxylate ligand: single-molecule magnet behaviour and luminescence properties

The reactions of LnIII ions with a versatile pyridyl-decorated dicarboxylic acid ligand lead to a series of novel three-dimensional (3D) Ln-MOFs, [Ln3(pta)4(Hpta)(H2O)]·xH2O (Ln = Dy (1), Eu (2), Gd (3), Tb (4), H2pta = 2-(4-pyridyl)-terephthalic acid, x = 6 for 1, 2.5 for 2, 1.5 for 3 and 2 for 4). The Ln3+ ions act as the nine-coordinated Muffin spheres, linking to each other to generate trinuclear {Ln3(OOC)6N2} SBUs, which are further extended to be interesting 3D topology architectures. To the best of our knowledge, the Dy-MOF exhibits a zero-field single-molecule magnet (SMM) behaviour with the largest effective energy barrier among the previously reported 3D MOF-based Dy-SMMs. The combined analyses of a dilution sample (1@Y) and ab initio calculation demonstrate that the thermally assisted slow relaxation is mainly attributed to the single-ion magnetism. Furthermore, fluorescence measurements reveal that H2pta can sensitize EuIII and TbIII characteristic luminescence

Hydrolase–like catalysis and structural resolution of natural products by a metal–organic framework

The exact chemical structure of non–crystallising natural products is still one of the main challenges in Natural Sciences. Despite tremendous advances in total synthesis, the absolute structural determination of a myriad of natural products with very sensitive chemical functionalities remains undone. Here, we show that a metal–organic framework (MOF) with alcohol–containing arms and adsorbed water, enables selective hydrolysis of glycosyl bonds, supramolecular order with the so–formed chiral fragments and absolute determination of the organic structure by single–crystal X–ray crystallography in a single operation. This combined strategy based on a biomimetic, cheap, robust and multigram available solid catalyst opens the door to determine the absolute configuration of ketal compounds regardless degradation sensitiveness, and also to design extremely–mild metal–free solid–catalysed processes without formal acid protons.This work was supported by the Ministero dell’Istruzione, dell’Università e della Ricerca (Italy) and the MINECO (Spain) (Projects CTQ2016-75671-P, CTQ 2017-86735-P, RTC-2017-6331-5, Severo Ochoa program SEV-2016-0683 and Excellence Unit “Maria de Maeztu” MDM-2015-0538). R.B. thanks the MIUR (Project PON R&I FSE-FESR 2014–2020) for grant. L.B wishes to thank Italian MIUR for grant n. AIM1899391–1 in the framework of the project “Azione I.2, Mobilità dei Ricercatori, PON R&I 2014–2020”. Thanks are also extended to the “2019 Post-doctoral Junior Leader-Retaining Fellowship, la Caixa Foundation (ID100010434 and fellowship code LCF/BQ/PR19/11700011” (J. F.- S.). S. S.-N. thanks ITQ for the concession of a contract. D.A. acknowledges the financial support of the Fondazione CARIPLO/“Economia Circolare: ricerca per un futuro sostenibile” 2019, Project code: 2019–2090, MOCA. E.P. acknowledges the financial support of the European Research Council under the European Union’s Horizon 2020 research and innovation program/ERC Grant Agreement No. 814804, MOF-reactors

Hierarchical Assembly of a Micro- and Macroporous Hydrogen-Bonded Organic Framework with Tailored Single-Crystal Size

Porous organic molecular materials represent an emergent field of research in Chemistry and Materials Science due to their unique combination of properties. To enhance their performance and expand the number of applications, the incorporation of hierarchical porosity is required, as exclusive microporosity entails several limitations. However, the integration of macropores in porous organic molecular materials is still an outstanding challenge. Herein, we report the first example of a hydrogen-bonded organic framework (MM-TPY) with hierarchical skeletal morphology, containing stable micro- and macroporosity. The crystal size, from micro to centimetre scale, can be controlled in a single step without using additives or templates. The mechanism of assembly during the crystal formation is compatible with a skeletal crystal growth. As proof of concept, we employed the hierarchical porosity as a platform for the dual, sequential and selective co-recognition of molecular species and microparticles.J.F.-S. thanks “Ramón y Cajal“ program (RYC2019-02794-I), MINECO (Spain) (Projects PID2019−104778GB−I00 and Excellence Unit “Maria de Maeztu” CEX2019−000919−M) and Generalitat Valenciana (SEJI/2020/034). E.V.R.F. thanks Ministerio de Ciencia e innovación (PID2020-116998RB-I00) and Ministerio de Educación y Formación Profesional (PRX21/00407)