Academic literature on the topic 'Metal-Organic Polyhedron'

This thesis describes the design, synthesis and characterisation of a series of novel metal-organic frameworks constructed from Cu(II) paddlewheels and polydentate aromatic carboxylate ligands. Gas sorption applications of these porous materials have been studied, with an emphasis on hydrogen storage. The effects of cage wall functionalisation within the frameworks, internal BET surface areas and pore volumes, and open Cu(II) sites on H2 adsorption by these materials are investigated. Chapter 1 introduces the current status of H2 storage in metal-organic framework materials. Extended metal-organic structures exhibiting large surface areas and high total pore volumes are favourable for H2 storage at high pressures and cryogenic temperatures. The strategy of utilising metal-organic polyhedra as secondary building blocks in the assembly of highly porous frameworks with high structural stability is discussed. Chapter 2 describes the synthesis of a highly porous (3,24)-connected metal-organic polyhedral framework (denoted NOTT-112) constructed from a nanosized hexacarboxylate linker and {CU2(COO)4} paddlewheels. The framework of NOT- 112 is composed of three types of metal-organic polyhedral cages: cuboctahedra, truncated tetrahedra and truncated octahedra. Desolvated NOTT-112 shows a very large apparent surface area of 3800 m2 g-l (BET) and high H2 storage capacity of 7.07 wt% (excess) at 35 bar at 77 K (total H2 uptake of 10.0 wt% at 77 bar and 77 K), making it one of the best materials for H2 storage at cryogenic temperatures and high pressures. In Chapter 3, neutron powder diffraction (NPD) studies on D2 (deuterium)-loaded NOTT-1l2 give the insight into the mechanism of H2 adsorption in this polyhedral MOF with coordinatively unsaturated Cu(II) sites. NPD experiments reveal that the exposed Cu(II) sites within the smallest cuboctahedral cages in NOTT-112 are the first and strongest binding sites for D2 in this material giving an overall discrimination between the two types of exposed Cu(II) sites within one {CU2} paddlewheel unit. Thus, NPD studies provide, for the first time, direct structural evidence demonstrating that a specific geometrical arrangement of exposed Cu(II) sites, in this case within a [Cu24(isophthalate)24] cuboctahedral cage, strengthens the interactions between D2 molecules and open metal sites. In the second part of this chapter, partially deuterated MOF NOTT-112-d13 was synthesised for inelastic neutron scattering experiments. In Chapter 4, four isostructural metal-organic polyhedral cage based frameworks (denoted NOTT-l13, NOTT-114, NOTT-115 and NOTT-118) with (3,24)-connected topology have been synthesised by combining hexacarboxylate isophthalate linkers with {CU2(COO)4} paddlewheels. All four frameworks have the same cub octahedral cage structure constructed from 24 isophthalates from the ligands and 12 {CU2(COO)4} paddlewheel moieties. The frameworks differ only in the functionality of the central core of the hexacarboxylate ligands with phenyl, trimethylphenyl, phenyl amine and triphenylamine moieties in NOTT-118, NOTT-113, NOTT-114 and NOTT-115, respectively. The desolvated framework materials shows high BET surface areas of 3265, 2970, 3424 and 3394 m2 g-l for NOTT-118, NOTT-l13, NOTT-114 and NOTT-115, respectively. Desolvated NOTT-l13 and NOTT-114 show high total H2 adsorption capacities of 6.7 wt% and 6.8 wt% at 77 K and 60 bar, respectively. Desolvated NO TT -118 and NOTT -115 have significantly higher total H2 uptakes of 8.0 wt% and 7.5 wt% under the same conditions, respectively. Analysis of the heats of adsorption (QsD for H2 reveals that with a triphenylamine moiety in the cage wall, desolvated NOTT-115 shows the highest value of Qs/ for these four materials indicating that functionalisation of the cage walls with more aromatic rings can enhance the H2/framework interactions. In contrast, measurement of Qs/ reveals that the amine substituted tris-alkynylbenzene core used in NOTT-114 gives a notably lower H2/framework binding energy. NOTT-112 to NOTT-115 also show high CH4 adsorption capacities (104-124 cm\STP) cm -3) at 20 bar and room temperature. The amine-functionalised NOTT-114 exhibits strong CO2-framework interaction and high CO2 storage capacity of 22.9 mmol g-1 at 20 bar and 298 K. Chapter 5 describes the linker expansion strategy used in construction of highly porous MOFs. Ultrahigh porosity can be achieved by expansion of the C3-symmetric hexacarboxylate linkers in the polyhedral frameworks. Two isostructural noninterpenetrated (3,24)-connected frameworks NOTT-116 and NOTT-119 have been synthesised based on elongated poly-aromatic hexacarboxylate linkers. Both frameworks of NO TT -116 and NOTT -119 consist of mesoporous cages with diameters up to ~ 3 nm. These two mesoporous materials show good thermal stability and can be fully desolvated without framework collapse by traditional activation method (heating the samples under vacuum). Desolvated NOTT -116 exhibits a significantly high BET surface area (4664 m2 g-I) and a high H2 adsorption capacity (saturated excess H2 uptake of 6.4 wt% at 77 K; total uptake of 9.2 wt% at 77 K and 50 bar). NO TT -119 shows a lower specific surface area of 4118 m2 g -I and a lower saturated excess H2 uptake of 5.6 wt% at 77 K, but a larger pore volume of 2.32 cm3 g-l, leading to a high total H2 uptake capacity of 9.2 wt% at 77 K and 60 bar. Another Cu(II) based MOF NOTT-120 constructed from a hexacarboxylate linker as large as 3.0 nm shows ultrahigh porosity with ultrahigh total pore volume of 2.81 cm3 g-l. Chapter 6 summarizes the H2 storage properties of the (3,24)-connected frameworks and draws an overall conclusions from this study.

Aquesta Tesi ha estat dedicada al disseny i implementació de noves tècniques de modificació post-sintètica (PSM) aplicades a material metal·loorgànics, principalment polímers de coordinació (CPs), xarxes metal·loorgàniques (MOFs) i políedres metal·loorgànics (MOPs), per tal de modificar les seves propietats fisicoquímiques a nivells inaccessibles a través de metodologies comuns de síntesi directa. La Tesi comença oferint una breu recapitulació bibliogràfica del camp dels materials metal·loorgànics, des dels seus inicis fins a la seva aplicació actual i perspectives de futur. Aquest capítol engloba els conceptes més importants sobre la seva síntesi i modificació post-sintètica, tant en els seus nodes metàl·lics com en els lligands orgànics que construeixen les xarxes; amb un particular èmfasi en les tècniques post-sintètiques desenvolupades fins avui. Seguidament, la tesi és dividida en quatre capítols extra, on cadascun d´ells s´enfoca en un procés de modificació post-sintètica concret. Inicialment, la Tesi es centra en la modificació post-sintètica de les subunitats metàl·liques de polímers de coordinació basats en lligand macrocíclics. La presència d´una font d´ions metàl·lics quelatats dins de la cavitat macrocíclica dels lligands indueix una transició de fase de monocristall a monocristall en contacte amb aigua, obtenint una distribució regular de subunitats; roda de paletes (paddlewheel); bimetàl·liques en la xarxa. Aquesta transició de fase és seguida a través de difracció de monocristall, així com a través de tècniques de caracterització espectroscòpiques i magnètiques. Al següent capítol es postula una tècnica de modificació post-sintètica fins ara inexplorada en el camp dels materials metal·loorgànics. Gràcies a la seva microporositat intrínseca, els MOF poden difondre gasos altament reactius a través de la seva xarxa, el que pot induir potencialment una modificació post-sintètica a través de reaccions sòlid-gas en qüestió de minuts. Per tal de provar aquesta hipòtesi, un MOF decorat amb funcionalitats olefina es va fer reaccionar difonent ozó a través de la seva xarxa. El producte de reacció obtingut presenta clara evidència de tenir dins dels seus canals de reacció l´esperat intermedi de reacció per a la reacció d´ozonòlisi, teòricament inestable. Aquest intermedi pot ser convertit en un pas posterior a grups aldehid o àcid carboxílic de forma quimiselectiva. Tot el procés és caracteritzat per tècniques de ressonància magnètica nuclear (RMN) i difracció de monocristall. Finalment, el coneixement adquirit en la modificació post-sintètica de CPs i MOFs es trasllada al camp dels materials zero-dimensionals. Concretament, aquesta Tesi demostra com políedres metal·loorgànics (MOPs) de rodi poden ser modificats en la seva perifèria a través de química de coordinació i covalent, modificant així les seves propietats fisicoquímiques (solubilitat) sense afectar a la seva integritat estructural. Aquesta modificació post-sintètica obra nous camins cap a l´explotació pràctica d´aquests materials, ja que degut a la seva estructura finita els MOPs poden ser vistos com nanopartícules estequiomètricament funcionalitzades amb solubilitat tuneable. Aquesta modificació post-sintètica permet a més introduït grups funcionals a la perifèria dels MOPs que no poden ser incorporats en síntesi directa. Així, a través d´un procés en dos passos, MOPs amb 24 grups amino o àcid carboxílic són sintetitzats. Ambdós grups presenten objectivament una de les químiques més riques en química covalent o de coordinació, respectivament, el que obra noves fronteres per a l´aplicació d´aquestes nanoplataformes.<br>Esta Tesis ha sido dedicada al diseño e implementación de nuevas técnicas de modificación post-sintética (PSM) aplicadas a material metalorgánicos, principalmente polímeros de coordinación (CPs), redes metalorgánicas (MOFs) y poliedros metalorgánicos (MOPS) , a fin de modificar sus propiedades fisicoquímicas a niveles inaccesibles a través de metodologías comunes de síntesis directa. La Tesis comienza ofreciendo una breve recapitulación bibliográfica del campo de los materiales metalorgánicos, desde sus inicios hasta su aplicación actual y perspectivas de futuro. Este capítulo engloba los conceptos más importantes sobre su síntesis y modificación post-sintética, tanto en sus nodos metálicos como en los ligandos orgánicos que construyen las redes; con un particular énfasis en las técnicas post-sintéticas desarrolladas hasta la fecha. Seguidamente, la Tesis es dividida en cuatro capítulos extra, donde cada uno de ellos se enfoca en un proceso de modificación post-sintética concreto. Inicialmente, la Tesis se centra en la modificación post-sintética de las subunidades metálicas de polímeros de coordinación basados en ligando macrocíclicos. La presencia de una fuente de iones metálicos quelatados dentro de la cavidad macrocíclicos los ligandos induce una transición de fase de monocristal monocristal en contacto con agua, obteniendo una distribución regular de subunidades; rueda de paletas (paddlewheel) bimetálica en la red. Esta transición de fase es seguida a través de difracción de monocristal, así como a través de técnicas de caracterización espectroscópicas y magnéticas. En el siguiente capítulo se postula una técnica de modificación post-sintética hasta ahora inexplorada en el campo de los materiales metalorgánicos. Gracias a su microporosidad intrínseca, los MOF pueden difundir gases altamente reactivos a través de su red, lo que puede inducir potencialmente una modificación post-sintética a través de reacciones sólido-gas en cuestión de minutos. Para probar esta hipótesis, un MOF decorado con funcionalidades olefina se hizo reaccionar difundiendo ozono a través de su red. El producto de reacción obtenido presenta clara evidencia de tener dentro de sus canales de reacción del esperado intermedio de reacción para la reacción de ozonólisis, teóricamente inestable. Este intermedio puede ser convertido en un paso posterior a grupos aldehído o ácido carboxílico de forma quimiselectiva. Todo el proceso es caracterizado por técnicas de resonancia magnética nuclear (RMN) y difracción de monocristal. Finalmente, el conocimiento adquirido en la modificación post-sintética de CPs y MOFs se traslada al campo de los materiales cero-dimensionales. Concretamente, esta Tesis demuestra cómo poliedros metalorgánicos (MOPS) de rodio pueden ser modificados en su periferia a través de química de coordinación y covalente, modificando así sus propiedades fisicoquímicas (solubilidad) sin afectar a su integridad estructural. Esta modificación post-sintética obra nuevos caminos hacia la explotación práctica de estos materiales, ya que debido a su estructura finita los MOPS pueden ser vistos como nanopartículas estequiométricamente funcionalizadas con solubilidad tuneable. Esta modificación post-sintética permite además introducido grupos funcionales en la periferia de los MOPS que no pueden ser incorporados en síntesis directa. Así, a través de un proceso en dos pasos, MOPS con 24 grupos amino o ácido carboxílico son sintetizados. Ambos grupos presentan objetivamente una de las químicas más ricas en química covalente o de coordinación, respectivamente, lo que abre nuevas fronteras para la aplicación de estas nanoplataformas.<br>The disserted Ph.D. Thesis was dedicated to the design and implementation of new post-synthetic modification (PSM) techniques to porous metal-organic materials, namely Coordination Polymers (CPs), Metal-Organic Frameworks (MOFs) and Metal-Organic Polyhedra (MOPs), in order to modify their physicochemical properties to inaccessible levels by common direct synthesis methodologies. The Thesis starts offering a brief bibliographic review of the evolution of metal-organic materials field, from their beginnings up to their actual applications and future perspectives. This chapter presents the most relevant concepts in their synthesis and their potential PSM, both in the metallic nodes or in the organic linkers that assemble the framework; with particular emphasis on the post-synthetic methodologies exploited up to date. Next, the Thesis is divided in four extra Chapters, each of them corresponding to a specific post-synthetic modification process. Initially, the Thesis focuses on the post-synthetic modification of the metallic subunits of macrocycle-based CPs. The presence of a second source of metal ions quelated inside the macrocyclic cavity induces a single-crystal-to-single-crystal phase transition in contact with water, obtaining a regular distribution of bimetallic paddlewheel subunits within the framework. Such transition was studied by single-crystal X-Ray diffraction techniques, as well as spectroscopic and magnetic characterization techniques. Next, an unexplored pathway for the PSM of MOFs is postulated. Thanks to their nanoporous structure, MOFs can diffuse highly-reactive gases through their framework in order to modify their structure through solid-gas reactions in a matter of minutes. To this end, an olefin-tagged MOF is post-synthetically modified by diffusing ozone gas through the porous channels of the material. The as-obtained reaction intermediate can be chemoselectively converted to either aldehyde or carboxylic acid groups without affecting the crystalline integrity of the material. The whole two-step process is characterized by Nuclear Magnetic Resonance (NMR) techniques, as well as single-crystal X-Ray diffraction. Afterwards, the post-synthetic modification of metal-organic architectures is extended to zero-dimensional materials. Concretely, it is demonstrated how the surface functionalization of Rhodium (II)-based Metal-Organic Polyhedra, both through coordination or covalent chemistries, is able to tune their solubility within a wide range of solvents, without affecting the scaffold&#8217;s integrity. This post-modification opens up new pathways for exploiting these materials. Because of their finite structure, MOPs can be seen as stoichiometrically-functionalized nanoparticles with tunable solubility. Such acquired knowledge is then applied to expand the available roster of Rh(II)-based MOPs. Through a two-step protection/deprotection strategy, two unprecedented Rh-MOPs with 24 free carboxylate or amino groups on their periphery are synthesized, unobtainable by direct synthesis methodologies. Both groups arguably present one of the richest chemistries in coordination and covalent chemistry, respectively, thus opening new pathways and frontiers towards the application of these materials.

Two new mesoporous metal–organic frameworks (DUT-75 and DUT-76) with exceptional ethene uptake were obtained using carbazole dicarboxylate based metal–organic polyhedra as supermolecular building blocks. The compounds have a total pore volume of 1.84 and 3.25 cm³ gˉ¹ and a specific BET surface area of 4081 and 6344 m² gˉ¹, respectively, and high gas uptake at room temperature and high pressure.

Self-assembly is a key step to obtain functional supramolecular objects towards complex matter. With self-assembly of metal ions and well-designed polytopic ligands is possible to access a particular class of supramolecular functional materials: metal-organic polygons and polyhedra endowed with confined space, and functional properties deriving from the building blocks. Herein, firstly is presented a system that in solution self-assembles in a collection of Cu(II) based boxes: a rhomboid and a triangle in dynamic equilibrium. This system is a small constitutional dynamic library (CDL). The designed introduction of well-suited guests allows to orchestrate the system response and select the triangular box by host-guest interactions. This system is an excellent bench test to explore the possibility to modulate the reactivity of guest molecules. Two examples of reactivity in the environment of the triangular host are here reported: the oxidation of a guest molecule under soft conditions and an extremely selective C-N bonds cleavage of another guest molecule. The nature of this multifaceted system has been unraveled by a combination of FT-IR spectroscopy, absorption spectroscopy and single crystal structural studies. Afterward, the synthesis of two new ligands libraries, a series of bis-β-diketone ligands and a series of tris-β-diketone ligands, specifically designed for the self-assembly of metallo-supramolecular cages, has been developed. The two libraries have been combined with both transition metal and lanthanoid ions in order to self-assemble metal-organic polyhedra. By reaction of the tris-β-diketone with Fe3+ ions, the rational design of and the self-assembly of a series of Fe4L4 supramolecular tetrahedra with space confined cavities able to host guest molecules, has been achieved. The formation of the capsules is confirmed by single crystal X-ray diffraction studies. The bis-β-diketone ligands have been reacted with Eu3+ ions leading to the self-assembly of a series of charged [Eu2L4]2-¬ and neutral [Eu2L3] dimeric capsules. In this systems, the structural features of metallo-supramolecular cages are combined with the peculiar optical properties of lanthanoid ions, leading to the self-assembly of luminescent coordination-driven capsules. The capsules have been studied through ESI-MS and 1H-NMR analyses. Luminescence and quantum yields have been characterized.<br>L’auto-assemblaggio, ovvero l’organizzazione spontanea e reversibile di componenti preesistenti in strutture supramolecolari, è un processo che può essere utilizzato per la preparazione di sistemi con proprietà funzionali, tramite. Nello specifico, tramite auto-assemblaggio di ioni metallici e leganti politopici è possibile generare una particolare classe di materiali funzionali supramolecolari: poligoni e poliedri metallo-organici dotati di tasche e spazi confinati di dimensione molecolare. In questo lavoro viene dapprima presentato un sistema basato su Cu(II) e un legante bis-β-dichetonato. In soluzione i componenti si auto-assemblano in una serie di box supramolecolari: un dimero ed un trimero in equilibrio dinamico tra loro. Questo sistema è una piccola libreria costituzionale dinamica (CDL). L’equilibrio tra i due costituenti della CDL può essere orchestrato tramite l’introduzione di piccole molecole che, venendo accomodate nella tasca molecolare della specie trimerica, riescono a selezionarla tramite interazioni di tipo host-guest. Questo sistema si è un eccellente modello per studiare la reattività di piccole molecole ospitate in spazi confinati. In questo lavoro sono presentati due esempi di reattività di piccole molecole ospitate nella tasca triangolare: un ossidazione in condizioni blande e la rottura selettiva di un legame C-N. Queste reazioni sono state studiate con una combinazione di spettroscopia FT-IR, UV-Vis e diffrazione a raggi X su cristallo singolo In seguito, è stata sviluppata la sintesi di due nuove librerie di leganti, una serie di leganti bis-β-dichetoni e una serie di leganti tris-β-dichetoni, progettati specificatamente per poter formare capsule metallo-supramolecolari. La reazione di questi leganti con metalli di transizione e con ioni lantanoidi porta alla formazione di poliedri metallo-organici. Nello specifico, l’auto-assemblaggio dei leganti tris-β-dichetoni con lo ione Fe3+ porta alla formazione di tetraedri supramolecolari, di formula generale Fe4L4. Tali capsule sono caratterizzate dalla presenza di tasche di dimensioni sufficienti a contenere piccole molecole. La struttura delle capsule tetraedriche è stata confermata tramite diffrazione a raggi X su cristallo singolo. L’auto-assemblaggio dei leganti bis-β-dichetoni con lo ione Eu3+ porta alla formazione di una serie di capsule dimeriche che possono essere cariche negativamente ([Eu2L4]2-¬) oppure neutre ([Eu2L3]). Questo sistema presenta proprietà funzionali: la luminescenza dello ione lantanoide è attivata tramite effetto antenna indotto dal legante. La formazione di queste capsule metallo-supramolecolari luminescenti è stata studiata tramite spettrometria ESI-MS e spettroscopia 1H-NMR. Infine sono state caratterizzate le proprietà di fotoluminescenza (emissione e rese quantiche) dei sistemi [Eu2L4]2-¬.

A highly porous metal–organic framework Cu2(BBCDC) (BBCDC = 9,9′-([1,1′-[b with combining low line]iphenyl]-4,4′-diyl)[b with combining low line]is(9H-[c with combining low line]arbazole-3,6-[d with combining low line]i[c with combining low line]arboxylate) (DUT-49) with a specific surface area of 5476 m2 g−1, a pore volume of 2.91 cm3 g−1, a H2 excess uptake of 80 mg g−1 (77 K, 50 bar), a CO2 excess uptake of 2.01 g g−1 (298 K, 50 bar) and an exceptionally high excess methane storage capacity of 308 mg g−1 (298 K, 110 bar) was obtained using an extended tetratopic linker<br>Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

A highly porous metal–organic framework Cu2(BBCDC) (BBCDC = 9,9′-([1,1′-[b with combining low line]iphenyl]-4,4′-diyl)[b with combining low line]is(9H-[c with combining low line]arbazole-3,6-[d with combining low line]i[c with combining low line]arboxylate) (DUT-49) with a specific surface area of 5476 m2 g−1, a pore volume of 2.91 cm3 g−1, a H2 excess uptake of 80 mg g−1 (77 K, 50 bar), a CO2 excess uptake of 2.01 g g−1 (298 K, 50 bar) and an exceptionally high excess methane storage capacity of 308 mg g−1 (298 K, 110 bar) was obtained using an extended tetratopic linker.<br>Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Despite the plethora of information regarding cellular crowding and its importance on modulating protein function the effects of confinement on biological molecules are often overlooked when investigating their physiological function. Recently however, the encapsulation of biomolecules in solid state matrices (NafionTM, sol-gels, zirconium phosphate,etc.) has increased in importance as a method for examining protein conformation and dynamics in confined space as well as novel applications in biotechnology. Biotechnological applications include, but are not limited to, bioremediation, biosensors, biocatalysts, etc. In order to better utilize solid state materials as substrates for biological molecules an understanding of the effects of encapsulation on the detailed dynamics associated with physiological function is required as well as a complete characterization of the physical properties associated with the space in which the biological molecule is to be confined. The focus of this research is to probe the effects of confinement on the thermodynamics of ligand photo-release/rebinding to the prototypical heme protein, myoglobin, encapsulated within sol-gel glasses utilizing photoacoustic calorimetry (PAC) and photothermal beam deflection (PBD). Optical spectroscopies (including optical absorption and fluorescence) have also been employed to characterize the molecular environments of materials including Zr-phosphate and metal organic polyhedral (MOPs), thought to be good candidates for novel bio-hybrid materials. The assembly mechanisms associated with MOPs were also examined in order to develop a foundation through which new, bio-compatible MOPs can be designed. Overall the results presented here represent a technological breakthrough in the application of fast calorimetry to the study of proteins in confined space. This will allow for the first time the acquisition of detailed thermodynamic maps associated with the well-choreographed biomolecular dynamics in confined environments.

Polytopes of the highest dimension of molecules of compounds of inorganic and organic chemistry are considered on specific examples. It is shown that they all have dimensions greater than three. They may include polytopes of a known shape, discussed in previous chapters, but in general they differ significantly from the standard shapes. These include linear and nonlinear chains of metal atoms with ligands, closed chains of metal atoms with ligands, clusters with ligands and a metal polyhedral backbone. A class of polytopic prismahedrons (a special type of polytopes of higher dimension) is considered, from which parallelotopes of higher dimension are formed, which are necessary for constructing n-dimensional spaces, using them to create extended nanomaterials based on clusters of chemical compounds.