Search results for "frameworks"

Nanoporosity, Inclusion Chemistry, and Spin Crossover in Orthogonally Interlocked Two-Dimensional Metal-Organic Frameworks

2015

[Fe(tvp)(2)(NCS)(2)] (1) (tvp=trans-(4,4-vinylenedipyridine)) consists of two independent perpendicular stacks of mutually interpenetrated two-dimensional grids. This uncommon supramolecular conformation defines square-sectional nanochannels (diagonal approximate to 2.2nm) in which inclusion molecules are located. The guest-loaded framework 1@guest displays complete thermal spin-crossover (SCO) behavior with the characteristic temperature T-1/2 dependent on the guest molecule, whereas the guest-free species 1 is paramagnetic whatever the temperature. For the benzene-guest derivatives, the characteristic SCO temperature T-1/2 decreases as the Hammet sigma(p) parameter increases. In general, …

Peptide Metal–Organic Frameworks for Enantioselective Separation of Chiral Drugs

2017

We report the ability of a chiral Cu(II) 3D MOF based on the tripeptide Gly-L-His-Gly (GHG) for the enantioselective separation of metamphetamine and ephedrine. Monte Carlo simulations suggest that chiral recognition is linked to preferential binding of one of the enantiomers as result of either stronger or additional H-bonds with the framework that lead to energetically more stable diastereomeric adducts. Solid phase extraction (SPE) of a racemic mixture by using Cu(GHG) as extractive phase permits isolating more than 50% of the (+)-ephedrine enantiomer as target compound in only four minutes. To the best of our knowledge, this represents the first example of a MOF capable of separating ch…

Tunable Spin-Crossover Behavior of the Hofmann-like Network {Fe(bpac)[Pt(CN) 4 ]} through Host-Guest Chemistry

2013

A study of the spin-crossover (SCO) behavior of the tridimensional porous coordination polymer {Fe(bpac)[Pt(CN)4]} (bpac=bis(4-pyridyl) acetylene) on adsorption of different mono- and polyhalobenzene guest molecules is presented. The resolution of the crystal structure of {Fe(bpac)[Pt(CN) 4]}A?G (G=1,2,4-trichlorobenzene) shows preferential guest sites establishing I?A?A?A?I? stacking interactions with the host framework. These host-guest interactions may explain the relationship between the modification of the SCO behavior and both the chemical nature of the guest molecule (electronic factors) and the number of adsorbed molecules (steric factors). Copyright © 2013 WILEY-VCH Verlag GmbH & …

Metal-functionalized covalent organic frameworks as precursors of supercapacitive porous N-doped graphene

2017

Covalent Organic Frameworks (COFs) based on polyimine with several metal ions (FeIII, CoII and NiII) adsorbed into their cavities have shown the ability to generate N-doped porous graphene from their pyrolysis under controlled conditions. These highly corrugated and porous graphene sheets exhibit high values of specific capacitance, which make them useful as electrode materials for supercapacitors.

Ultrathin Films of 2D Hofmann-Type Coordination Polymers: Influence of Pillaring Linkers on Structural Flexibility and Vertical Charge Transport

2019

Searching for novel materials and controlling their nanostructuration into electronic devices is a challenging task ahead of chemists and chemical engineers. Even more so when this new application requires an exquisite control over the morphology, crystallinity, roughness and orientation of the films produced. In this context, it is of critical importance to analyze the influence of the chemical composition of perspective materials on their properties at the nanoscale. We report the fabrication of ultrathin films (thickness < 30 nm) of a family of FeII Hofmann-like coordination polymers by using an optimized liquid phase epitaxy (LPE) set-up. The series [Fe(L)2{Pt(CN)4}] (L = pyridine, pyri…

Elucidating Gating Effects for Hydrogen Sorption in MFU-4-Type Triazolate-Based Metal-Organic Frameworks Featuring Different Pore Sizes

2011

A highly porous member of isoreticular MFU-4-type frameworks, [Zn(5)Cl(4)(BTDD)(3)] (MFU-4l(arge)) (H(2)-BTDD=bis(1H-1,2,3-triazolo[4,5-b],[4',5'-i])dibenzo[1,4]dioxin), has been synthesized using ZnCl(2) and H(2)-BTDD in N,N-dimethylformamide as a solvent. MFU-4l represents the first example of MFU-4-type frameworks featuring large pore apertures of 9.1 Å. Here, MFU-4l serves as a reference compound to evaluate the origin of unique and specific gas-sorption properties of MFU-4, reported previously. The latter framework features narrow-sized pores of 2.5 Å that allow passage of sufficiently small molecules only (such as hydrogen or water), whereas molecules with larger kinetic diameters (e.…

Ti-based robust MOFs in the combined photocatalytic degradation of emerging organic contaminants.

2022

Photocatalysis process is a promising technology for environmental remediation. In the continuous search of new heterogeneous photocatalysts, metal–organic frameworks (MOFs) have recently emerged as a new type of photoactive materials for water remediation. Particularly, titaniumbased MOFs (Ti-MOFs) are considered one of the most appealing subclass of MOFs due to their promising optoelectronic and photocatalytic properties, high chemical stability, and unique structural features. However, considering the limited information of the reported studies, it is a hard task to determine if real-world water treatment is attainable using Ti-MOF photocatalysts. In this paper, via a screening with seve…

EXPERIMENTAL EVALUATION OF THE ACCURACY OF RFID BASED LOCALIZATION SYSTEMS FOR INDUSTRIAL WAREHOUSES

2009

Humour as a symptom of research trends in translation studies

2017

This article is an overview of translation studies applied to the case of humour, divided into four parts, plus an extensive bibliography. The first part goes over humour translation as a relevant object of research and why it is worthy of more academic attention. Humour translation should not be dealt with or looked upon as a strange body within translation studies. Part two is an overview of key contributions to the field, from Spain and elsewhere, covering a considerable number of authors and theories. Part three focuses on promising areas of interest for researchers and illustrates how audiovisual translation is a good instance of dynamism within the field, connecting all this to the ri…

Stimuli-responsive magnetic coordination polymers: from crystals to nanoparticles

2013

El trabajo descrito en esta tesis se enmarca en el ámbito de los polímeros de coordinación (PC). Estos sistemas representan un área importante dentro de la Química de los Materiales, siendo principalmente interesantes sus aplicaciones en catálisis, electrónica y óptica. Su origen data de principios de los años 60, donde se produjo la primera revisión de estructuras de compuestos inorgánicos que formaban cadenas.1 Los PC están formados por ligandos orgánicos y metales enlazados por enlaces de coordinación que se extienden infinitamente en 1, 2 o 3 dimensiones. En cuanto a su versatilidad química, las estructuras y propiedades varían en función de los metales o ligandos utilizados. Así pues, …