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Metal Organic Framework

Wen-Bo Pei, Zhi-Yu Jing, Li-Te Ren, Yabo Wang, Jiansheng Wu, Ling Huang, Raymond Lau, Wei Huang
Unexpected Sc/Ln codoped rare earth metal-organic frameworks (RE-MOFs) molecular alloys (MAs) based on an oxalic acid ligands were obtained. Calcination of the RE-MOFs MAs gave the corresponding codoped rare earth oxides a strong and nearly pure red color upconversion luminescence. It allows the resulting lanthanide ion (Ln3+ ) doped upconversion materials a wide range of applications from optical communications to disease diagnosis. Moreover, the pyrolysis RE-MOFs MAs precursor has demonstrated to be an effective preparation method for a uniform Ln-doped Sc2 O3 system...
August 17, 2018: Inorganic Chemistry
M Viswanathan
Copper guanidinium formate (CuGF) is an ABX3-type metal-organic framework bearing a polar space group, housing a guest-host connectivity between the guanidinium and formate ions. With the maiden data-set based on single-crystal neutron diffraction, we report the discovery of the guest orderliness which surprisingly accommodates an enhancement for low-symmetric CuGF, while the scenario is contrasting for the high-symmetric Mn cousin. We provide an in-depth evaluation of the inter-guanidinium scheme and thus propose the mechanism behind this unusual effect...
August 17, 2018: Physical Chemistry Chemical Physics: PCCP
Dae-Hyun Nam, Oleksandr S Bushuyev, Jun Li, Phil De Luna, Ali Seifitokaldani, Cao-Thang Dinh, F Pelayo Garcia de Arquer, Yuhang Wang, Zhiqin Liang, Andrew H Proppe, Chih Shan Tan, Petar Todorovic, Osama Shekhah, Christine M Gabardo, Jea Woong Jo, Jongmin Choi, Min-Jae Choi, Se-Woong Baek, Junghwan Kim, David Sinton, Shana O Kelley, Mohamed Eddaoudi, Edward H Sargent
The electrochemical carbon dioxide reduction reaction (CO2 RR) produces diverse chemical species. Cu clusters with a judiciously-controlled surface coordination number (CN) provide active sites that simultaneously optimize selectivity, activity, and efficiency for CO2 RR. Here we report a strategy involving metal-organic framework (MOF)-regulated Cu cluster formation that shifts CO2 electroreduction toward multiple-carbon product generation. Specifically, we promoted undercoordinated sites during the formation of Cu clusters by controlling the structure of the Cu dimer, the precursor for Cu clusters...
August 16, 2018: Journal of the American Chemical Society
Yuanyuan Zhang, Xuan Zhang, Jiafei Lyu, Ken-Ichi Otake, Xingjie Wang, Louis R Redfern, Christos D Malliakas, Zhanyong Li, Timur Islamoglu, Bo Wang, Omar K Farha
Zr-based metal-organic frameworks (MOFs) have been known for their excellent stability, however, due to the high connectivity of the Zr6 nodes, it is challenging to introduce flexibility into Zr-MOFs. Here we present a flexible Zr-MOF named NU-1400 comprising 4-connected Zr6 nodes and tetratopic linkers. It exhibits guest-dependent structural flexibility with up to 48% contraction in the unit cell volume as evidenced by single-crystal X-ray studies. The expanded or contracted conformations of NU-1400 showed drastically different reactivity toward the hydrolysis of a nerve agent simulant owing to the size-selective effect toward the reactant...
August 16, 2018: Journal of the American Chemical Society
Chung-Wei Kung, Ana E Platero-Prats, Riki J Drout, Junmo Kang, Timothy C Wang, Cornelius O Audu, Mark C Hersam, Karena W Chapman, Omar K Farha, Joseph T Hupp
A representative mesoporous metal-organic-framework (MOF) material, NU-1000, has been rendered electronically conductive via a robust inorganic approach that permits retention of MOF crystallinity and porosity. The approach is based on condensed-phase grafting of molecular tin species onto the MOF nodes via irreversible reaction with hydroxyl and aqua ligands presented at the node surface, a self-limiting process termed Solvothermal Installation (of metal ions) in MOFs (SIM, a solution-phase analog of atomic layer deposition in MOFs)...
August 16, 2018: ACS Applied Materials & Interfaces
Manesh Kumar, Mukaddus Kariem, Haq Nawaz Sheikh, Antonio Frontera, Saikat Kumar Seth, Amanpreet Kaur Jassal
Single crystal X-ray diffraction studies reveal the formation of six new coordination polymers (CPs) with the general formulas [Dy(3,5-pdc)(3,5-pdcH)(H2O)2]n·nH2O (1), [Pr2(3,5-pdc)3(H2O)2]n·2n(H2O) (2), [Sm2(3,5-pdc)3(H2O)3]n·nH2O (3), {[Eu2(3,5-pdc)3(H2O)3(CH3CHO)]n·n[2(H2O)(DMF)]} (4), {[Gd2(3,5-pdc)3 (H2O)2]n·2nH2O} (5) and [Er(3,5-pdc)(adip)0.5(H2O)]n (6) (where 3,5-pdc2- = fully deprotonated; 3,5-pdcH- = partially deprotonated 3,5-pyridinedicarboxylic acid; adip2- = fully deprotonated adipic acid; and DMF = dimethylformamide) by solvothermal self-assembly of lanthanide ions with rigid 3,5-pyridinedicarboxylic acid as a linker and adipic acid as an auxiliary flexible spacer (only coordinated in CP 6)...
August 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Paul J Saines, Nicholas C Bristowe
Materials with magnetic interactions between their metal centres play a tremendous role in modern technologies and can exhibit unique physical phenomena. In recent years, magnetic metal-organic frameworks and coordination polymers have attracted significant attention because their unique structural flexibility enables them to exhibit multifunctional magnetic properties or unique magnetic states not found in the conventional magnetic materials, such as metal oxides. Techniques that enable the magnetic interactions in these materials to be probed at the atomic scale, long established to be key for developing other magnetic materials, are not well established for studying metal-organic frameworks and coordination polymers...
August 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Chang Guo, Suying Xu, Anila Arshad, Leyu Wang
We successfully fabricated 19F magnetic resonance imaging (MRI) nanoprobes by partly replacing the 2-methylimidazolate of the metal organic framework (MOF) matrix ZIF-8, of which the strong 19F MRI signal displays an interesting pH dependence property, indicating its great potential as a 19F MRI contrast agent for stimuli-responsive imaging with high penetration depth and low background.
August 16, 2018: Chemical Communications: Chem Comm
Filip Formalik, Michael Fischer, Justyna Rogacka, Lucyna Firlej, Bogdan Kuchta
The adequate choice of the interaction model is essential to reproduce qualitatively and estimate quantitatively the experimentally observed characteristics of materials or phenomena in computer simulations. Here we present the results of a benchmarking of density-functional theory calculations of rigid and flexible metal-organic frameworks (MOFs). The stability of these systems depends on the dispersion interactions. We compare the performance of two functionals, Perdew-Burke-Ernzerhof (PBE) and PBE designed for solids, with and without the dispersion corrections (D2 and TS), in reproducing the high-accuracy low-temperature X-ray and neutron diffraction data for both groups of MOFs...
August 14, 2018: Journal of Chemical Physics
Chi-Ta Yang, Aseem Rajan Kshirsagar, Azzam Charaf Eddin, Li-Chiang Lin, Roberta Poloni
By combining first-principles calculations and classical molecular simulations, we provide the atomistic-level understanding towards the notable change in CO2 adsorption upon light treatment in two recently reported photoactive metal-organic frameworks, PCN-123 and Cu2(AzoBPDC)2(AzoBiPyB). We demonstrate that the reversible decrease in gas adsorption upon isomerization can be primarily attributed to the blocking of the strong adsorbing sites at the metal nodes by azobenzene molecules in cis configuration. The same mechanism is found to apply also to other molecules, e...
August 15, 2018: Chemistry: a European Journal
Lifeng Yang, Xili Cui, Zhaoqiang Zhang, Qiwei Yang, Zongbi Bao, Qilong Ren, Huabin Xing
The implement of one-step removal of multi-component gases based on single material will significantly improve the efficiency of separation processes but still remains challenging, due to the difficulty to precisely fabricate the porous materials with multiple binding sites that are tailored for the different guest molecules. Here, we report a novel niobium oxide-fluoride anion-pillared interpenetrated material ZU-62 (also termed as NbOFFIVE-2-Cu-i, NbOFFIVE = NbOF52-) featuring asymmetric O/F node coordination for the simultaneous removal of trace propyne and propadiene from the propylene, industrial processes relevant for the production of polymer-grade propylene...
August 15, 2018: Angewandte Chemie
Guillaume Collet, Timothée Lathion, Céline Besnard, Claude Piguet, Stéphane Petoud
We have designed a rigid photocleavable dianthracene-based ligand that reacts with ytterbium as coordination metal ion for the creation of a class of tridimensional light-degradable metal-organic framework (MOF). We demonstrated that we can obtain a high level of control on the disassembly of the MOF formed with this ligand which can be triggered either through light irradiation or temperature increase. The reversible 4π-4π photodimerization is the intrinsic chemical mechanism ruling the ligand and MOF cleavage...
August 15, 2018: Journal of the American Chemical Society
Fei-Long Hu, Yan Mi, Chen Zhu, Brendan F Abrahams, Pierre Braunstein, Jian-Ping Lang
Regioselective photodimerization of trans-4-styrylpyridine (4-spy) derivatives is performed using pseudorotaxane-like Zn-based metal organic frameworks MOFs as templates. The formation of rctt-HT (head-to-tail) dimers is achieved by confining pairs of coordinated 4-spy derivative ligands within hexagonal windows and then irradiating them with UV light. It is also possible to achieve a photodimerization reaction where two different substituted 4-spy ligands are included in such a MOF material. The ether bond formation is employed to protect the sensitive -OH group of HO-spy and the methyl group of CH3O-spy is subsequently removed after the formation of cyclobutane derivative in the CH3O-Spy-based MOF...
August 14, 2018: Angewandte Chemie
Sitong Liu, Jisheng Zhou, Huaihe Song
We develop a general strategy for the design of a series of 2D N-rich carbon-based nanomaterials through the thermal exfoliation of layered metal-hexamine framework microcrystals. By a facile pyrolysis, the sharply generated gases escape from the layered precursors, leading to the exfoliation of the layers and successful preparation of 2D carbon-based nanomaterials. This strategy can readily skip the complicated morphology engineering process of 2D metal-organic frameworks to produce 2D N-rich carbon-based nanomaterials on a large scale...
August 15, 2018: Chemical Communications: Chem Comm
Qilong Gao, Naike Shi, Qiang Sun, Andrea Sanson, Ruggero Milazzo, Alberto Carnera, He Zhu, Saul H Lapidus, Yang Ren, Qingzhen Huang, Jun Chen, Xianran Xing
The understanding of the negative thermal expansion (NTE) mechanism is vital not only for the development of new NTE compounds but also for effectively controlling thermal expansion. Here, we report an interesting isotropic NTE property in cubic GaFe(CN)6 Prussian blue analogues (α l = -3.95 × 10-6 K-1 , 100-475 K), which is a new example to understand the complex NTE mechanism. A combined study of synchrotron X-ray diffraction, X-ray total scattering, X-ray absorption fine structure, neutron powder diffraction, and density functional theory calculations shows that the NTE of GaFe(CN)6 originates from the low-frequency phonons (< ∼100 cm-1 ), which are directly related to the transverse vibrations of the atomic -Ga-N≡C-Fe- chains...
August 14, 2018: Inorganic Chemistry
Cong-Cong Shen, Ya-Nan Liu, Xin Wang, Xiao-Xiang Fang, Zhi-Wei Zhao, Nan Jiang, Liu-Bo Ma, Xiao Zhou, Tuck-Yun Cheang, An-Wu Xu
Metal-organic framework (MOF)-based materials possess numerous attractive characteristics; however, the application of MOF-based photocatalysts in the area of visible-light photocatalytic H2 evolution is still in its infancy. Herein, we develop a series of novel UiO-66-NH2-based composites with embedded NiO nanoparticles via solvothermal treatment and subsequent calcination. Their characterizations demonstrate intimate lattice-level contacts between UiO-66-NH2 photocatalysts and NiO nanoparticles. By optimizing each component, even without noble metal loading, the U6N-NiO-2 sample (the weight ratio of NiO to U6N-NiO-2 is theoretically calculated to be ca...
August 14, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Yong-Peng Li, Shu-Ni Li, Yu-Cheng Jiang, Man-Cheng Hu, Quan-Guo Zhai
Presented herein is a magnesium-organic framework (SNNU-88) incorporated with active hydroquinone groups, which exhibits not only remarkable semiconductor sensing for traces of ammonia vapor (5-100 ppm), but also extra-high fluorescence response to liquid NH3·H2O through an unusual turn-off (0-1.5 ppm) and turn-on (3.0-100 ppm) luminescence sensing mechanism at room temperature. Such bifunctional quantitative ammonia detection together with the extraordinary sensitivity and selectivity, fast response, and good reusability makes SNNU-88 one of the most powerful ammonia sensors...
August 14, 2018: Chemical Communications: Chem Comm
Simeng Dai, Yan Yuan, Jiangsheng Yu, Jian Tang, Jie Zhou, Weihua Tang
Metal-organic frameworks (MOFs) provide great opportunities for synthesizing advanced electrode materials with hierarchical hollow architectures for energy storage. Herein, we report the facile fabrication of core-sheath nanoarrays (NAs) on carbon cloth (CC@CoO@S-Co3O4) for binder-free electrode materials with MOFs as versatile scaffolds. The hollow S-doped Co3O4 sheath has been facilely prepared using a two-step synthetic protocol, which includes the surface etching of CoO nanowires for synchronous in situ growth of well-aligned ZIF-67 and its following hydrothermal process...
August 14, 2018: Nanoscale
Lauren N McHugh, Matthew J McPherson, Laura J McCormick, Samuel A Morris, Paul S Wheatley, Simon J Teat, David McKay, Daniel M Dawson, Charlotte E F Sansome, Sharon E Ashbrook, Corinne A Stone, Martin W Smith, Russell E Morris
Highly porous metal-organic frameworks (MOFs), which have undergone exciting developments over the past few decades, show promise for a wide range of applications. However, many studies indicate that they suffer from significant stability issues, especially with respect to their interactions with water, which severely limits their practical potential. Here we demonstrate how the presence of 'sacrificial' bonds in the coordination environment of its metal centres (referred to as hemilability) endows a dehydrated copper-based MOF with good hydrolytic stability...
August 13, 2018: Nature Chemistry
Baosheng Ge, Yanyan Xu, Haoru Zhao, Haixiang Sun, Yaoli Guo, Wenguang Wang
Mixed matrix membranes (MMMs) attract great attention due to their outstanding gas separation performance. The compatibility between the fillers and the polymer matrix is one of the key points for the preparation of high-performance MMMs. In this work, MMMs consisting of metal-organic frameworks (MOFs) of amine-modified Cu-BTC (NH₂-Cu-BTC; BTC = 1,3,5-benzenetricarboxylic acid) and submicrometer-sized amine-modified Cu-BTC (sub-NH₂-Cu-BTC) incorporated into a Pebax-1657 polymer were fabricated for the gas separation...
August 13, 2018: Materials
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