Biologically derived metal organic frameworks

Samantha Lynn Anderson, Kyriakos Stylianou
Elsevier, 2017
Article

Résumé

Metal organic frameworks (MOFs) are extended structures composed of a network of organic ligands and metal ions or clusters connected to each other via coordination bonds. The numerous choices of organic ligands and metal coordination geometries have led to the construction of porous MOFs with various compositions, network topologies, pore sizes and shapes and they possess high surface areas and low densities. The structures of MOFs can be tailor-tuned in such a way that any desired ligand or/and metal ion can be incorporated; this has given to researchers the advantage of designing MOFs for a targeted application. Within this review, we overview recent examples of a sub-class of MOFs namely biologically derived MOFs (bio-MOFs), made of multifunctional and commercially available biologically derived ligands (bio-ligands) such as: amino acids, peptides, nucleobases and saccharides and focus on their coordination chemistry with a variety of metals. Central to this review are four tables detailing the coordination modes of bio-ligands to metals, along with a visual representation of the bio-MOF that is subsequently formed. Through the detailed analysis of these structures, we highlight the structural impact of these ligands on the structure, and their contribution to the MOF properties and applications. Finally, we showcase the potential of bio-MOFs in several research areas such as CO2 capture, separation, catalysis, drug delivery and sensing. (C) 2017 Elsevier B.V. All rights reserved.

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https://infoscience.epfl.ch/record/232236?ln=fr

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Samantha Lynn Anderson, Kyriakos Stylianou
Elsevier, 2017
Article

Résumé

Official source

https://infoscience.epfl.ch/record/232236?ln=fr

À propos de ce résultat

Concepts associés (9)

Concepts associés

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Publications associées (12)

Publications associées

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Syntheses, structures and properties of silver(I) complexes constructed from nitrogenous aromatic heterocyclic carboxylic acids and N-donor ligands

Chi Wai Cheung, Hong-Ling Gao

Four new coordination complexes with silver(I) ions and nitrogenous aromatic heterocyclic carboxylic ligands, namely [AB(4)(Pac)(Phen)(4)]center dot 8H(2)O (1), {[AB(4)(Pztc)(bPe)(3)] center dot 5H(2)O}(n) (2), [Ag-4(Hmptc)(2)(4,4'-bPY)(3)] center dot 4.5H(2)O (3), and [Ag-2(H(2)mPtc)(2)(2,2'-bPY)(2)] (4) (H(4)Pztc = pyrazine-2,3,5,6-tetracarboxylic acid, H(3)mptc = 6-methyl2,3,5-pyridine-tricarboxylic acid, phen = 1,10-phenanthroline, bpe = trans-1,2-bis(4-pyridyl)ethylene, 4,4'bpy = 4,4'-bipyridine, 2,2'-bpy = 2,2'-bipyridine), have been synthesized by the self-assembly reactions and characterized by X-ray diffraction single crystal structure analysis, elemental analysis, IR, PXRD, fluorescence and thermal analysis. In I, four crystallographically independent silver(l) atoms are found to coordinate with only one pztc(4-) ligand. Complex 2 is a 2D grid structure. Complexes 3 and 4 are extended from OD to 2D or 1D by the Ag center dot center dot center dot O interactions. (C) 2014 Elsevier B.V. All rights reserved.

Elsevier2014

Chargement

This thesis is concerned with supramolecular architectures assembled at metal surfaces. The investigations pursued two objectives. On the one hand, the focus was placed on the fabrication of low-dimensional surface-supported network structures by applying the concepts of conventional three-dimensional supramolecular chemistry at surfaces. Three main driving forces were explored for the construction of low-dimensional assemblies: hydrogen bonding, metal coordination and ionic interactions. The realized structures were characterized by scanning tunneling microscopy (STM) under ultra-high vacuum conditions. In particular, the interplay between the adsorbate-substrate coupling and lateral adsorbate interactions was addressed in the experiments. Further, the electronic and magnetic properties of the fabricated coordination structures were investigated. This characterization was done by x-ray absorption experiments at the synchrotron facility in Grenoble. Moreover, the response of the metal units and open cavity structures to the adsorption of large organic and small gas molecules was studied by temperature controlled STM experiments. The first part of the thesis deals with hydrogen bonded supramolecular assemblies. Simple aromatic carboxylic acids were employed to study the assembly principles and in particular effects arising from the substrate and molecular structure. The investigation of TPA (1,4-benzenedicarboxylic acid) adlayers on Cu(100) at different substrate temperatures revealed how the protonation status of the carboxyl moieties affects the topology of the assemblies. Further, the influence of the molecular backbone functionality and symmetry is addressed in comparative investigations on TPA and PDA (2,5-pyrazinedicarboxylic acid) as well as BDA (4,4'-biphenyldicarboxylic acid) and SDA (4',4" trans-ethene-l,2-diyl-bisbenzoic acid) adlayers on Cu(100). In the second part of the thesis, metal-ligand interactions were employed for the construction of supramolecular architectures at a Cu(100) surface. The concepts of conventional coordination chemistry were successfully applied at the surface. Iron atoms in conjunction with rod-like aromatic molecular linkers comprising carboxyl, pyridyl and hydroxyl functional groups assemble into a rich variety of open network structures with distinctly arranged mono- and diiron coordination centers and well-defined cavities. The results show that the adsorbate-substrate coupling considerably affects the local coordination environment of the iron units when the molecular backbone length is varied. The occurrence of structural isomerism in open network structures is addressed in a comparative study of heterofunctional and homofunctional linker molecules. It is shown that the former ligand allows only one topologically pure structure while the other linker forms two phases with different topology. The hydroxyl ligand has been used to construct distorted hexagonal coordination networks containing threefold coordinated single iron atoms. The comparison between the networks on Cu(100) and Ag(111) surfaces shows marked differences, which are attributed to adsorbate-substrate interactions. Finally, a novel design strategy for the fabrication of two-dimensional coordination structures at surfaces is introduced by using alkali metal ions in conjunction with carboxylate ligands. The interaction between the components is dominated by electrostatic forces and is of intermediate bond strength as in the case of hydrogen bonding and transition metal coordination. It is expected, that substrate symmetry and registry plays a larger role in the network formation, because the ionic interaction is not directional. The chemical as well as magnetic properties of the fabricated coordination networks are examined in the last part of the thesis. The adsorption of C60 molecules on open network structures reveals how cavity size and chemical functionality affect the bond strength to the guest molecules as well as the number of accommodated C60 molecules. Since transition metal clusters, and in particular diiron units, are the catalytic active centers in various proteins, the reactivity of various mono- and diiron coordination structures to molecular oxygen was investigated in temperature controlled STM experiments. In particular, the focus was placed on the structural relaxation upon gas adsorption and chemical reaction. At last, the magnetic properties of the metal coordination centers are addressed in XMCD experiments. The iron units are found to be paramagnetic at temperatures down to 5 K and show distinct magnetic anisotropy and magnetization loops. These experiments demonstrate that surface-supported metal coordination structures are a promising class of materials for applications in the field of heterogenous catalysis and surface magnetism.

EPFL2005

Chargement

Structure, dynamics and catalytic activity of ruthenium(II)-arene phosphine complexes

This thesis encompasses work on the coordination chemistry and catalytic activity of half sandwich ruthenium(II)-arene phosphine complexes. The investigation of phosphine dissociation and association reactions of these complexes represents the unifying theme of this study and, in addition to providing fundamental insights into the coordination chemistry of these compounds, allowed structure-activity relationships to be made and assisted in the development of new synthetic procedures. The thesis is organised into three parts according to the type of phosphine ligand investigated. The dissociation characteristics and catalytic activity of bis-phosphine complexes are presented in Chapter 2. The former properties were established by kinetic studies of ligand exchange and gasphase fragmentation analysis by tandem mass spectrometry, and helped to rationalise trends in the observed catalytic activity for the hydrogenation of styrene to ethylbenzene. The more active complexes were also shown to be chemoselective catalysts for the hydrogenation of aldehydes in the presence of olefinic bonds. Mechanistic studies were carried out in order to rationalise the preferential hydrogenation of aldehydes, which is consequently suggested to proceed via an ionic outer-sphere mechanism. Chapter 3 describes investigations on the coordination chemistry of ruthenium(II)-arene complexes containing diphosphine ligands. Complexes containing κ1-coordinated diphosphine ligands, with or without triphenylphosphine as a co-ligand, were prepared or characterised as the corresponding borane adducts. Mechanistic studies, including determination of enthalpies, entropies and, in two cases, volumes of activation, for the chelation reactions of the isolated κ1-diphosphine complexes were undertaken. The coordination chemistry of a chiral diphosphine, (R)-BINAPO, was also investigated; the synthesis of complexes containing this ligand in a range of coordination modes was achieved. The final chapter concerns the reactivity and catalytic activity of ruthenium(II) complexes containing (PPh2CH2)3CMe (triphos). Investigations of the catalytic activity of ruthenium(II)-arene complexes containing the κ2-coordinated triphos ligand were carried out together with pertinent reactivity studies and comparisons to structural analogues, which helped rationalise the observed activities. The reactivity and catalytic chemistry of one of the structural analogues, a ruthenium(II)-acetate κ3-triphos complex, was also investigated in detail as it proved to be a highly active catalyst for the hydrogenation of 1-alkenes.

EPFL2007

Chargement

EPFL2005

Structure, dynamics and catalytic activity of ruthenium(II)-arene phosphine complexes

EPFL2007