Polynuclear complexes as precursor templates for hierarchical microporous graphitic carbon: An unusual approach

YesA highly porous carbon was synthesized using a coordination complex as an unusual precursor. During controlled pyrolysis, a trinuclear copper complex, [CuII3Cl4(H2L)2]·CH3OH, undergoes phase changes with melt and expulsion of different gases to produce a unique morphology of copper-doped carbon which, upon acid treatment, produces highly porous graphitic carbon with a surface area of 857 m2 g–1 and a gravimetric hydrogen uptake of 1.1 wt % at 0.5 bar pressure at 77 K.EPSRC (EP/R01650X/1 for VPT, and EP/E040071/1 for MT) and the University of Bristo

Matériaux hybrides multifonctionnels (Elaboration et propriétés d'hydroxydes lamellaires de métaux de transition magnétiques et luminescents)

STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Study of the oxidative esterification of furfural catalyzed by Au 25 (glutathione) 18 nanocluster deposited on zirconia

International audienceAu/ZrO 2 catalyst prepared from Au 25 (SG) 18 nanoclusters (SG stands for glutathione) deposited on ZrO 2 has shown to be an efficient system for the oxidative esterification of furfural with methanol. The influence of the supported nanoclusters was studied and showed that partial calcination of the supported nanoclusters at 300 °C was sufficient for a quantitative formation of methyl-2-furoate even in the absence of a base. In the presence of 0.27 mol% of Au, initial activities up to 250 h-1 were obtained at 100 °C under 6 bar of O 2. The reactivity was extended to the oxidative esterification of furfuryl alcohol and the formation of various products and intermediates was discussed

Post-synthetic functionalization and ligand exchange reactions in gold(i) phenylthiolate-based coordination polymers

SSCI-VIDE+CDFA+ADMInternational audienceGold thiolate coordination polymers (CPs) are anisotropic materials with 1D or 2D networks exhibiting a large palette of photoluminescence properties. In this paper, we show that, from both lamellar acid and ester, [Au(p-SPhCO2X)]n CPs (X = H, Me), it is possible to perform post-synthesis esterification or saponification reactions. Three new 2D phases with X = Na, K and Cs were isolated. In addition, ligand exchange reactions were carried out from 1D [Au(p-SPh)]n CP and 2D [Au(p-SPhCO2X)]n CPs (X = H, Me) and the transformations from 1D to 2D structures and vice versa point out a mechanism of dissolution and recrystallization that is governed by the nature of the ligands and the presence of weak interactions. The obtained compounds exhibit solid state and RT photoemission characteristic of their structure

Thermal control of the defunctionalization of supported Au25(glutathione)18 catalysts for benzyl alcohol oxidation

Au25(SG)18 (SG – glutathione) clusters deposited on ZrO2 nanoparticles have been used as a catalyst for benzyl alcohol oxidation. Calcination was performed at different temperatures to study the ligand and particle size effect on the catalytic activity. In contrast to most gold nanoclusters which have to be completely defunctionalized for maximum catalytic activity, the partially defunctionalized Au25(SG)18@ZrO2 catalyst, thermally treated at 300 °C, exhibits full conversion of benzyl alcohol within 15 h under atmospheric pressure with 94% selectivity towards benzaldehyde

How far the Chemistry of the Self-Assembly Monolayers on Gold Surfaces Affects their Work Function?

International audienceSelf-assembled monolayers composed of various long-chain aliphatic molecules and different tail functional groups have been synthesized on the Au(111) surface and characterized by Kelvin Probe Force Microscopy and Ultraviolet Photoelectron Spectroscopy. Carboxy, amino, thio and methyl terminal groups have been considered in the design of self-assembled monolayers with different aliphatic chain lengths (from C6 to C16). The work function measurements by Kelvin Probe Force Microscopy have been carried out under controled and room atmosphere. Remarkably, a reduction of the relative humidity from 40 % to 3 % has induced a work function shift up to 0.3 eV. As expected, the changes of the chain length of the aliphatic moiety and of the tail group have a significant impact on the tuning of the measured work function (3.90 eV for dodecanethiol versus 4.57 eV for mercaptohexadecylamine). Surprisingly, the change of the net dipole moment of the tail group (sign and amplitude) does not dominate the work function variations. In contrast, the change of the chain length and the possibility of the tail group to form a complex hydrogen-bond network between molecules, lead to significant modulations of the work function. In order to interpret these original findings, density functional theory models of equivalent self-assembled monolayers adsorbed on the Au(111) surface have been developed at an unprecedented level of description with large supercells including simultaneously 27 coadsorbed molecules and weak van der Waals interactions between them. Such large systems have allowed the theoretical modeling of complex hydrogen-bond networks between molecules when possible (carboxy tail group). The comparison between computed and measured work functions shows a striking agreement, thus allowing the disentanglement of the previously mentioned competing effects. This consistency between experiment and theory will help designing the electronic properties of self-assembled monolayers in the context of molecular electronics and organic transistors

Metal–organic frameworks for water desalination

Rapid industrialization and ever-increasing global population culminate in continuous upsurge in freshwater crisis worldwide. The most reliable and promising solution to this crisis is utilizing sea-water as the freshwater source, and desalination technologies pave the way for efficient production of freshwater from sea-water. In this regard, membrane-based desalination method comes forth owing to its' efficient separation, operational ease, and low-energy consumption. Metal-organic frameworks (MOFs), the most explored crystalline porous materials, show tremendous promise as membrane-materials for desalination owing to their structural diversity, tunability, and porous voids which provide secondary water channels. Given significant advances are made in MOF-materials for desalination in the past few years, it is crucial to systematically summarize the recent progress and development of this field. In this review, a brief overview of various saline water systems and prerequisites for desalination are first presented. Then, advanced fabrication strategies MOF-membranes followed by the recent progress in MOF-materials for various desalination processes such as reverse osmosis and forward osmosis are systematically summarized. Finally, the authors' perspectives on the unsolved scientific and technical challenges and opportunities for MOF-integrated membranes toward real-world implementation are proposed. With further systematic development, MOF-materials promise to provide an ideal platform for next-generation desalination technology

Photoluminescent coordination polymer bulk glasses and laser-induced crystallization

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