630-76-2Relevant academic research and scientific papers
Zinc(ii) and cadmium(ii) amorphous metal-organic frameworks (aMOFs): Study of activation process and high-pressure adsorption of greenhouse gases
Almá?i, Miroslav,Bourrelly, Sandrine,Király, Nikolas,Vilková, Mária,Zeleňák, Vladimír
, p. 20137 - 20150 (2021/06/28)
Two novel amorphous metal-organic frameworks (aMOFs) with chemical composition {[Zn2(MTA)]·4H2O·3DMF}n (UPJS-13) and {[Cd2(MTA)]·5H2O·4DMF}n (UPJS-14) built from Zn(ii) and Cd(ii) ions and extended tetrahedral tetraazo-tetracarboxylic acid (H4MTA) as a linker were prepared and characterised. Nitrogen adsorption measurements were performed on as-synthesized (AS), ethanol exchanged (EX) and freeze-dried (FD) materials at different activation temperatures of 60, 80, 100, 120, 150 and 200 °C to obtain the best textural properties. The largest surface areas of 830 m2 g-1 for UPJS-13 (FD) and 1057 m2 g-1 for UPJS-14 (FD) were calculated from the nitrogen adsorption isotherms for freeze-dried materials activated at mild activation temperature (80 °C). Subsequently, the prepared compounds were tested as adsorbents of greenhouse gases, carbon dioxide and methane, measured at high pressures. The maximal adsorption capacities were 30.01 wt% CO2 and 4.84 wt% CH4 for UPJS-13 (FD) and 24.56 wt% CO2 and 6.38 wt% CH4 for UPJS-14 (FD) at 20 bar and 30 °C.
Rigid Multidimensional Alkoxyamines: A Versatile Building Block Library
Matt, Yannick,Wessely, Isabelle,Gramespacher, Lisa,Tsotsalas, Manuel,Br?se, Stefan
supporting information, p. 239 - 245 (2020/12/17)
Since the discovery of the “living” free-radical polymerization, alkoxyamines were widely used in nitroxide-mediated polymerization (NMP). Most of the known alkoxyamines bear just one functionality with only a few exceptions bearing two or more alkoxyamine units. Herein, we present a library of novel multidimensional alkoxyamines based on commercially available, rigid, aromatic core structures. A versatile approach allows the introduction of different sidechains which have an impact on the steric hindrance and dissociation behavior of the alkoxyamines. The reaction to the alkoxyamines was optimized by implementing a mild and reliable procedure to give all target compounds in high yields. Utilization of biphenyl, p-terphenyl, 1,3,5-triphenylbenzene, tetraphenylethylene, and tetraphenyl-methane results in linear, trigonal, square planar, and tetrahedral shaped alkoxyamines. These building blocks are useful initiators for multifold NMP leading to star-shaped polymers or as a linker for the nitroxide exchange reaction (NER), to obtain dynamic frameworks with a tunable crosslinking degree and self-healing abilities.
Preparation of Recyclable and Versatile Porous Poly(aryl thioether)s by Reversible Pd-Catalyzed C–S/C–S Metathesis
Morandi, Bill,Rivero-Crespo, Miguel A.,Toupalas, Georgios
supporting information, p. 21331 - 21339 (2021/12/17)
Porous organic materials (polymers and COFs) have shown a number of promising properties; however, the lability of their linkages often limits their robustness and can hamper downstream industrial application. Inspired by the outstanding chemical, mechanical, and thermal resistance of the 1D polymer poly(phenylene sulfide) (PPS), we have designed a new family of porous poly(aryl thioether)s, synthesized via a mild Pd-catalyzed C–S/C–S metathesis-based method, that merges the attractive features common to porous polymers and PPS in a single material. In addition, the method is highly modular, allowing to easily introduce application-oriented functionalities in the materials for a series of environmentally relevant applications including metal capture, metal sensing, and heterogeneous catalysis. Moreover, despite their extreme chemical resistance, the polymers can be easily recycled to recover the original monomers, offering an attractive perspective for their sustainable use. In a broader context, these results clearly demonstrate the untapped potential of emerging single-bond metathesis reactions in the preparation of new, recyclable materials.
All-Carbon-Linked Continuous Three-Dimensional Porous Aromatic Framework Films with Nanometer-Precise Controllable Thickness
B?rjesson, Karl,Evans, Austin M.,Ratsch, Martin,Yang, Yizhou,Ye, Chen,Zhang, Airui
supporting information, p. 6548 - 6553 (2020/04/30)
Inherently porous materials that are chemically and structurally robust are challenging to construct. Conventionally, dynamic chemistry is thought to be needed for the formation of uniform porous organic frameworks, but dynamic bonds can limit the stability of these materials. For this reason, all-carbon-linked frameworks are expected to exhibit higher stability performance than more traditional porous frameworks. However, the limited reversibility of carbon-carbon bond-forming reactions has restricted the exploration of these materials. In particular, the challenges associated with producing uniform thin films of all-carbon-linked frameworks has inhibited the study of these materials in applications where well-defined films are required. Here, we synthesize continuous and homogeneous films of two different all-carbon-linked three-dimensional porous aromatic frameworks with nanometer-precision thickness (PAF-1 and BCMP-2). This was accomplished by kinetically promoting surface reactivity while suppressing homogeneous nucleation. Through connection of the PAF film to a gold substrate via a self-assembled monolayer and use of flow conditions to continually introduce monomers, smooth and continuous PAF films can be grown with controlled thickness. This strategy allows traditional transition metal mediated carbon-carbon cross-coupling reactions to form porous, organic thin films. We expect that the chemical principles uncovered in this study will enable the synthesis of a variety of chemically and structurally diverse carbon-carbon-linked frameworks as high-quality films, which are inaccessible by conventional methods.
Remarkable Structural Diversity between Zr/Hf and Rare-Earth MOFs via Ligand Functionalization and the Discovery of Unique (4, 8)-c and (4, 12)-connected Frameworks
Angeli, Giasemi K.,Batzavali, Danai,Mavronasou, Katerina,Tsangarakis, Constantinos,Stuerzer, Tobias,Ott, Holger,Trikalitis, Pantelis N.
supporting information, p. 15986 - 15994 (2020/10/18)
Ligand modification in MOFs provides great opportunities not only for the development of functional materials with new or enhanced properties but also for the discovery of novel structures. We report here that a sulfone-functionalized tetrahedral carboxylate-based ligand is capable of directing the formation of new and fascinating MOFs when combined with Zr4+/Hf4+ and rare-earth metal cations (RE) with improved gas-sorption properties. In particular, the resulting M-flu-SO2 (M: Zr, Hf) materials display a new type of the augmented flu-a net, which is different as compared to the flu-a framework formed by the nonfunctionalized tetrahedral ligand. In terms of properties, a remarkable increase in the CO2 uptake is observed that reaches 76.6% and 61.6% at 273 and 298 K and 1 bar, respectively. When combined with REs, the sulfone-modified linker affords novel MOFs, RE-hpt-MOF-1 (RE: Y3+, Ho3+, Er3+), which displays a fascinating (4, 12)-coordinated hpt net, based on nonanuclear [RE9(μ3-?)2(μ3-??-)12(-COO)12] clusters that serve as hexagonal prismatic building blocks. In the absence of the sulfone groups, we discovered that the tetrahedral linker directs the formation of new RE-MOFs, RE-ken-MOF-1 (RE: Y3+, Ho3+, Er3+, Yb3+), that display an unprecedented (4, 8)-coordinated ken net based on nonanuclear RE9-clusters, to serve as bicapped trigonal prismatic building units. Successful activation of the representative member Y-ken-MOF-1 reveals a high BET surface area and total pore volume reaching 2621 m2 g-1 and 0.95 cm3 g-1, respectively. These values are the highest among all RE MOFs based on nonanuclear clusters and some of the highest in the entire RE family of MOFs. The present work uncovers a unique structural diversity existing between Zr/Hf and RE-based MOFs that demonstrates the crucial role of linker design. In addition, the discovery of the new RE-hpt-MOF-1 and RE-ken-MOF-1 families of MOFs highlights the great opportunities existing in RE-MOFs in terms of structural diversity that could lead to novel materials with new properties.
Temperature Controls Guest Uptake and Release from Zn4L4 Tetrahedra
Zhang, Dawei,Ronson, Tanya K.,Güryel, Songül,Thoburn, John D.,Wales, David J.,Nitschke, Jonathan R.
supporting information, p. 14534 - 14538 (2019/10/11)
We report the preparation of triazatruxene-faced tetrahedral cage 1, which exhibits two diastereomeric configurations (T1 and T2) that differ in the handedness of the ligand faces relative to that of the octahedrally coordinated metal centers. At lower temperatures, T1 is favored, whereas T2 predominates at higher temperatures. Host-guest studies show that T1 binds small aliphatic guests, whereas T2 binds larger aromatic molecules, with these changes in binding preference resulting from differences in cavity size and degree of enclosure. Thus, by a change in temperature the cage system can be triggered to eject one bound guest and take up another.
Anhydrous proton conduction in porous organic networks
Klumpen,Winterstein,Papastavrou,Senker
supporting information, p. 21542 - 21549 (2018/11/20)
Solid electrolyte separators within fuel cells enable efficient charge transport and prevent a mass bypass between the two half cells. Hydrated systems, like Nafion, reach unprecedented proton conductivities at ambient temperatures, but the demanding humidity management prevents their use beyond 80 °C, hence limiting the efficiency of current polymer-based systems. As such, water free and chemically inert, solid materials with excellent conductivities between 100 °C and 200 °C, are of high interest. A promising approach is the incorporation of heavier amphoteric molecules into micro- and mesoporous frameworks. Stronger host-guest interactions allow for higher temperatures, while still maintaining sufficient mobility and efficient transport pathways. Here, we present a systematic study investigating the influence of porosity, framework topology and dimensionality as well as framework functionality and charge carrier uptake on the proton conductivity for six porous organic networks (PONs) loaded with imidazole via gas phase adsorption. The resulting materials were thoroughly characterized by multinuclear NMR and IR spectroscopy and physisorption as well as powder X-ray diffraction and DSC experiments, revealing homogeneous distribution of the amphoteric guests within the pore structure. Electrochemical impedance spectroscopy up to 130 °C revealed remarkable conductivities of up to 10?3 S cm?1 under anhydrous conditions. We found 3D networks to favour high imidazole loading leading to high proton conductivities based on the Grotthuss mechanism. In contrast, 2D networks showed a lower guest molecule uptake and thus lower proton conductivities, which were governed by vehicle transport. Additional acid/base functionalities within the frameworks seem to have a negative effect on the proton conduction.
Two-Photon Absorption Properties and Structures of BODIPY and Its Dyad, Triad and Tetrad
Yang, Jian,Rousselin, Yoann,Bucher, Léo,Desbois, Nicolas,Bolze, Frédéric,Xu, Hai-Jun,Gros, Claude P.
, p. 838 - 844 (2018/10/05)
A series consisting of a dyad, a triad and a tetrad containing either two, three and four BODIPY units, respectively, has been synthesized and fully characterized and compared to two mono-BODIPY analogs (used as references). The one- and two-photon photophysical properties have been measured and the X-ray structures of four of the BODIPY derivatives have been determined. In the 700–900 nm range, the two-photon absorption (TPA) cross sections range from 30 GM to 160 GM for these compounds.
Molecular Vise Approach to Create Metal-Binding Sites in MOFs and Detection of Biomarkers
Wang, Yang,Liu, Qi,Zhang, Qin,Peng, Bosi,Deng, Hexiang
, p. 7120 - 7125 (2018/06/15)
We report a new approach to create metal-binding site in a series of metal–organic frameworks (MOFs), where tetratopic carboxylate linker, 4′,4′′,4′′′,4′′′′-methanetetrayltetrabiphenyl-4-carboxylic acid, is partially replaced by a tritopic carboxylate linker, tris(4-carboxybiphenyl)amine, in combination with monotopic linkers, formic acid, trifluoroacetic acid, benzoic acid, isonicotinic acid, 4-chlorobenzoic acid, and 4-nitrobenzoic acid, respectively. The distance between these paired-up linkers can be precisely controlled, ranging from 5.4 to 10.8 ?, where a variety of metals, Mg2+, Al3+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Ag+, Cd2+ and Pb2+, can be placed in. The distribution of these metal-binding sites across a single crystal is visualized by 3D tomography of laser scanning confocal microscopy with a resolution of 10 nm. The binding affinity between the metal and its binding-site in MOF can be varied in a large range (observed binding constants, Kobs from 1.56×102 to 1.70×104 L mol?1), in aqueous solution. The fluorescence of these crystals can be used to detect biomarkers, such as cysteine, homocysteine and glutathione, with ultrahigh sensitivity and without the interference of urine, through the dissociation of metal ions from their binding sites.
Gold nanoparticles confined in imidazolium-based porous organic polymers to assemble a microfluidic reactor: Controllable growth and enhanced catalytic activity
Fang, Haobin,Sun, Shujian,Liao, Peisen,Hu, Ya,Zhang, Jianyong
supporting information, p. 2115 - 2121 (2018/02/09)
A synthetic strategy is developed to grow Au nanoparticles supported by imidazolium-based porous organic polymers (Au/IM-POPs) along the inner surface of a fused-silica microfluidic capillary. The thickness of the hybrid Au/IM-POP material layers can be tuned by changing the precursor concentration. A variety of imidazolium-based porous organic polymers are developed from tetrakis[4-(1-imidazolyl)phenyl]methane and bromo-functionalized linker molecules and fully characterized, which may be used to support Au nanoparticles. Additionally the IM-POPs and Au/IM-POPs show porosity and the ability to take up guest molecules. The capillary coated with Au/IM-POPs is further assembled to obtain a catalytic microfluidic reactor. The catalytic activity of Au nanoparticles supported by the porous imidazolium polymer is probed by using the reduction of nitrobenzene derivatives flowing through the microfluidic reactor. The catalytic microfluidic reactor demonstrates significantly enhanced turnover frequency magnitudes in comparison with the corresponding reactions under batch conditions.
