共查询到20条相似文献,搜索用时 15 毫秒
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Young Eun Cheon Myunghyun Paik Suh Prof. 《Angewandte Chemie (International ed. in English)》2009,48(16):2899-2903
Quick on the uptake : Palladium nanoparticles were fabricated simply by immersing {[Zn3(ntb)2(EtOH)2]?4 EtOH}n ( 1 ) in an MeCN solution of Pd(NO3)2 at room temperature, without any extra reducing agent. 3 wt % PdNPs@[ 1 ]0.54+(NO3?)0.54 significantly increase H2 uptake capacities, both at 77 K and 1 bar and at 298 K and high pressures (see picture, red curve) compared to [Zn3(ntb)2]n (black). ntb=4,4′,4′′‐nitrilotrisbenzoate.
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Dr. Jared B. DeCoste Dr. Mitchell H. Weston Patrick E. Fuller Trenton M. Tovar Gregory W. Peterson Dr. M. Douglas LeVan Dr. Omar K. Farha 《Angewandte Chemie (International ed. in English)》2014,53(51):14092-14095
We present a systematic study of metal–organic frameworks (MOFs) for the storage of oxygen. The study starts with grand canonical Monte Carlo simulations on a suite of 10 000 MOFs for the adsorption of oxygen. From these data, the MOFs were down selected to the prime candidates of HKUST‐1 (Cu‐BTC) and NU‐125, both with coordinatively unsaturated Cu sites. Oxygen isotherms up to 30 bar were measured at multiple temperatures to determine the isosteric heat of adsorption for oxygen on each MOF by fitting to a Toth isotherm model. High pressure (up to 140 bar) oxygen isotherms were measured for HKUST‐1 and NU‐125 to determine the working capacity of each MOF. Compared to the zeolite NaX and Norit activated carbon, NU‐125 has an increased excess capacity for oxygen of 237 % and 98 %, respectively. These materials could ultimately prove useful for oxygen storage in medical, military, and aerospace applications. 相似文献
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Lilin He Luming Yang Mircea Dinc Rui Zhang Jianlin Li 《Angewandte Chemie (International ed. in English)》2020,59(24):9773-9779
A molecular‐level understanding of transport and adsorption mechanisms of electrolyte ions in nanoporous electrodes under applied potentials is essential to control the performance of double‐layer capacitors. Here, in operando small‐angle neutron scattering (SANS) is used to directly detect ion movements into the nanopores of a conductive metal–organic framework (MOF) electrode under operating conditions. Neutron‐scattering data reveals that most of the void space within the MOF is accessible to the solvent. Upon the addition of the electrolyte sodium triflate (NaOTf), the ions are adsorbed on the outer surface of the protrusions to form a 30 Å layer instead of entering the ionophobic pores in the absence of an applied charging potential. The changes in scattering intensity when potentials are applied suggests the ion rearrangement in the micropores following different mechanisms depending on the electrode polarization. These observations shed insights on ion electrosorption in electrode materials. 相似文献
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Enamul Haque Nazmul Abedin Khan Jung Hwa Park Sung Hwa Jhung Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(3):1046-1052
A metal–organic framework material named MIL‐53(Fe), iron terephthalate, has been synthesized sovothermally at a relatively low temperature by not only conventional electric (CE) heating, but also by irradiation under ultrasound (US) and microwave (MW) conditions to gain an understanding of the accelerated syntheses induced by US and MW. The kinetics for nucleation and crystal growth were analyzed by measuring the crystallinity of MIL‐53(Fe) under various conditions. The nucleation and crystal growth rates were estimated from crystallization curves of the change in crystallinity with reaction time. The activation energies and pre‐exponential factors were calculated from Arrhenius plots. It was confirmed that the rate of crystallization (both nucleation and crystal growth) decreases in the order US>MW?CE, and that the accelerated syntheses under US and MW conditions are due to increased pre‐exponential factors rather than decreased activation energies. It is suggested that physical effects such as hot spots are more important than chemical effects in the accelerated syntheses induced by US and MW irradiation. The syntheses were also conducted in two steps to understand quantitatively the acceleration induced by MW and it was found that the acceleration in crystal growth is more important than the acceleration in nucleation, even though both processes are accelerated by MW irradiation. 相似文献
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Anjian Lan Kunhao Li Dr. Haohan Wu David H. Olson Dr. Thomas J. Emge Dr. Woosoek Ki Maochun Hong Dr. Jing Li Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(13):2334-2338
Sensors and sensitivity : A highly luminescent microporous metal–organic framework, [Zn2(bpdc)2(bpee)] (bpdc=4,4′‐biphenyldicarboxylate; bpee=1,2‐bipyridylethene), is capable of very fast and reversible detection of the vapors of the nitroaromatic explosive 2,4‐dinitrotoluene and the plastic explosive taggant 2,3‐dimethyl‐2,3‐dinitrobutane, through redox fluorescence quenching with unprecedented sensitivity (see spectra).
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Microporous metal–organic frameworks (MOFs) are comparatively new porous materials. Because the pores within such MOFs can be readily tuned through the interplay of both metal‐containing clusters and organic linkers to induce their size‐selective sieving effects, while the pore surfaces can be straightforwardly functionalized to enforce their different interactions with gas molecules, MOF materials are very promising for gas separation. Furthermore, the high porosities of such materials can enable microporous MOFs with optimized gas separation selectivity and capacity to be targeted. This Focus Review highlights recent significant advances in microporous MOFs for gas separation. 相似文献
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Dr. Weiqi Wang Dr. Lei Wang Prof. Yubin Huang Prof. Zhigang Xie Prof. Xiabin Jing 《化学:亚洲杂志》2016,11(5):750-756
A metal–organic framework (MOF)–protein conjugate, NH2‐MIL‐125(Ti)‐hemoglobin [MIL‐125(Ti)‐Hb], was synthesized by a covalent postmodification strategy. The crystalline structure was maintained after chemical and protein modification. The content of grafted Hb was tuned by the stoichiometric ratio and reached 50 wt % if the mass ratio of MIL‐125(Ti)/Hb was 1:1.25 in the feed. The oxygen‐transporting capacity of grafted Hb was kept, and the P50 (the half O2 pressure saturated with O2) and Hill coefficients of the MIL‐125(Ti)‐Hb conjugate were found to be 22.9 mm Hg and 2.35, respectively, which are close to the respective values of free Hb. All the results indicate that the MIL‐125(Ti)‐Hb conjugate could be potentially used as an oxygen carrier. 相似文献
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Perturbation of Spin Crossover Behavior by Covalent Post‐Synthetic Modification of a Porous Metal–Organic Framework 下载免费PDF全文
John E. Clements Dr. Jason R. Price Dr. Suzanne M. Neville Prof. Cameron J. Kepert 《Angewandte Chemie (International ed. in English)》2014,53(38):10164-10168
Covalent post‐synthetic modification is a versatile method for gaining high‐level synthetic control over functionality within porous metal–organic frameworks and for generating new materials not accessible through one‐step framework syntheses. Here we apply this topotactic synthetic approach to a porous spin crossover framework and show through detailed comparison of the structures and properties of the as‐synthesised and covalently modified phases that the modification reaction proceeds quantitatively by a thermally activated single‐crystal‐to‐single‐crystal transformation to yield a material with lowered spin‐switching temperature, decreased lattice cooperativity, and altered color. Structure–function relationships to emerge from this comparison show that the approach provides a new route for tuning spin crossover through control over both outer‐sphere and steric interactions. 相似文献
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Turn‐On Luminescence Sensing and Real‐Time Detection of Traces of Water in Organic Solvents by a Flexible Metal–Organic Framework 下载免费PDF全文
Antigoni Douvali Dr. Athanassios C. Tsipis Dr. Svetlana V. Eliseeva Prof. Stéphane Petoud Dr. Giannis S. Papaefstathiou Dr. Christos D. Malliakas Dr. Ioannis Papadas Dr. Gerasimos S. Armatas Dr. Irene Margiolaki Prof. Mercouri G. Kanatzidis Dr. Theodore Lazarides Dr. Manolis J. Manos 《Angewandte Chemie (International ed. in English)》2015,54(5):1651-1656
The development of efficient sensors for the determination of the water content in organic solvents is highly desirable for a number of chemical industries. Presented herein is a Mg2+ metal–organic framework (MOF), which exhibits the remarkable capability to rapidly detect traces of water (0.05–5 % v/v) in various organic solvents through an unusual turn‐on luminescence sensing mechanism. The extraordinary sensitivity and fast response of this MOF for water, and its reusability make it one of the most powerful water sensors known. 相似文献
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Encapsulation of an Interpenetrated Diamondoid Inorganic Building Block in a Metal–Organic Framework 下载免费PDF全文
Dr. Huabin Zhang Dr. Ping Lin Dr. Erxia Chen Dr. Yanxi Tan Dr. Tian Wen Prof. Ali Aldalbahi Prof. Saad M. Alshehri Prof. Yusuke Yamauchi Prof. Shaowu Du Prof. Jian Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(13):4931-4934
The first example of an inorganic–organic composite framework with an interpenetrated diamondoid inorganic building block, featuring unique {InNa}n helices and {In12Na16} nano‐rings, has been constructed and structurally characterized. This framework also represents a unique example of encapsulation of an interpenetrated diamondoid inorganic building block in a metal–organic framework. 相似文献
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Flexible and Hierarchical Metal–Organic Framework Composites for High‐Performance Catalysis 下载免费PDF全文
Dr. Ning Huang Hannah Drake Jialuo Li Dr. Jiandong Pang Dr. Ying Wang Shuai Yuan Qi Wang Peiyu Cai Dr. Junsheng Qin Prof. Dr. Hong‐Cai Zhou 《Angewandte Chemie (International ed. in English)》2018,57(29):8916-8920
The development of porous composite materials is of great significance for their potentially improved performance over those of individual components and extensive applications in separation, energy storage, and heterogeneous catalysis. Now mesoporous metal–organic frameworks (MOFs) with macroporous melamine foam (MF) have been integrated using a one‐pot process, generating a series of MOF/MF composite materials with preserved crystallinity, hierarchical porosity, and increased stability over that of melamine foam. The MOF nanocrystals were threaded by the melamine foam networks, resembling a ball‐and‐stick model overall. The resulting MOF/MF composite materials were employed as an effective heterogeneous catalyst for the epoxidation of cholesteryl esters. Combining the advantages of interpenetrative mesoporous and macroporous structures, the MOF/melamine foam composite has higher dispersibility and more accessibility of catalytic sites, exhibiting excellent catalytic performance. 相似文献
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Symmetry‐Guided Synthesis of Highly Porous Metal–Organic Frameworks with Fluorite Topology 下载免费PDF全文
Muwei Zhang Ying‐Pin Chen Mathieu Bosch Thomas Gentle III Kecheng Wang Dawei Feng Dr. Zhiyong U. Wang Prof. Dr. Hong‐Cai Zhou 《Angewandte Chemie (International ed. in English)》2014,53(3):815-818
Two stable, non‐interpenetrated MOFs, PCN‐521 and PCN‐523, were synthesized by a symmetry‐guided strategy. Augmentation of the 4‐connected nodes in the fluorite structure with a rigid tetrahedral ligand and substitution of the 8‐connected nodes by the Zr/Hf clusters yielded MOFs with large octahedral interstitial cavities. They are the first examples of Zr/Hf MOFs with tetrahedral linkers. PCN‐521 has the largest BET surface area (3411 m2 g‐1), pore size (20.5×20.5×37.4 Å) and void volume (78.5%) of MOFs formed from tetrahedral ligands. This work not only demonstrates a successful implementation of rational design of MOFs with desired topology, but also provides a systematic way of constructing non‐interpenetrated MOFs with high porosity. 相似文献
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A New Synthetic Route to Microporous Silica with Well‐Defined Pores by Replication of a Metal–Organic Framework 下载免费PDF全文
Dr. Atsushi Kondo Dr. Anthony Shoji Hall Prof. Thomas E. Mallouk Prof. Kazuyuki Maeda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(34):12148-12152
Microporous amorphous hydrophobic silica materials with well‐defined pores were synthesized by replication of the metal–organic framework (MOF) [Cu3(1,3,5‐benzenetricarboxylate)2] (HKUST‐1). The silica replicas were obtained by using tetramethoxysilane or tetraethoxysilane as silica precursors and have a micro–meso binary pore system. The BET surface area, the micropore volume, and the mesopore volume of the silica replica, obtained by means of hydrothermal treatment at 423 K with tetraethoxysilane, are 620 m2g?1, 0.18 mL g?1, and 0.55 mL g?1, respectively. Interestingly, the silica has micropores with a pore size of 0.55 nm that corresponds to the pore‐wall thickness of the template MOF. The silica replica is hydrophobic, as confirmed by adsorption analyses, although the replica has a certain amount of silanol groups. This hydrophobicity is due to the unique condensation environment of the silica precursors in the template MOF. 相似文献
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Water‐Mediated Proton Conduction in a Robust Triazolyl Phosphonate Metal–Organic Framework with Hydrophilic Nanochannels 下载免费PDF全文
Salma Begum Zhaoyang Wang Dr. Anna Donnadio Prof. Dr. Ferdinando Costantino Prof. Dr. Mario Casciola Dr. Rustem Valiullin Dr. Christian Chmelik Dr. Marko Bertmer Prof. Dr. Jörg Kärger Prof. Dr. Jürgen Haase Prof. Dr. Harald Krautscheid 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(29):8862-8866
The development of water‐mediated proton‐conducting materials operating above 100 °C remains challenging because the extended structures of existing materials usually deteriorate at high temperatures. A new triazolyl phosphonate metal–organic framework (MOF) [La3 L 4(H2O)6]Cl ? x H2O ( 1 , L 2?=4‐(4H‐1,2,4‐triazol‐4‐yl)phenyl phosphonate) with highly hydrophilic 1D channels was synthesized hydrothermally. Compound 1 is an example of a phosphonate MOF with large regular pores with 1.9 nm in diameter. It forms a water‐stable, porous structure that can be reversibly hydrated and dehydrated. The proton‐conducting properties of 1 were investigated by impedance spectroscopy. Magic‐angle spinning (MAS) and pulse field gradient (PFG) NMR spectroscopies confirm the dynamic nature of the incorporated water molecules. The diffusivities, determined by PFG NMR and IR microscopy, were found to be close to that of liquid water. This porous framework accomplishes the challenges of water stability and proton conduction even at 110 °C. The conductivity in 1 is proposed to occur by the vehicle mechanism. 相似文献
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Exchange of Coordinated Solvent During Crystallization of a Metal–Organic Framework Observed by In Situ High‐Energy X‐ray Diffraction 下载免费PDF全文
Dr. Yue Wu Matthew I. Breeze Dr. Guy J. Clarkson Dr. Franck Millange Prof. Dermot O'Hare Prof. Richard I. Walton 《Angewandte Chemie (International ed. in English)》2016,55(16):4992-4996
Using time‐resolved monochromatic high energy X‐ray diffraction, we present an in situ study of the solvothermal crystallisation of a new MOF [Yb2(BDC)3(DMF)2]?H2O (BDC=benzene‐1,4‐dicarboxylate and DMF=N,N‐dimethylformamide) under solvothermal conditions, from mixed water/DMF solvent. Analysis of high resolution powder patterns obtained reveals an evolution of lattice parameters and electron density during the crystallisation process and Rietveld analysis shows that this is due to a gradual topochemical replacement of coordinated solvent molecules. The water initially coordinated to Yb3+ is replaced by DMF as the reaction progresses. 相似文献
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