861533-46-2Relevant academic research and scientific papers
Molecular Insight into Fluorocarbon Adsorption in Pore Expanded Metal-Organic Framework Analogs
Barpaga, Dushyant,Bhattacharya, Papri,Brown, Craig M.,Fan, Yanzhong,Jenks, Jeromy J.,Maurin, Guillaume,McGrail, B. Peter,Motkuri, Radha Kishan,Shetty, Manish,Su, Cheng-Yong,Trump, Benjamin A.,Zheng, Jian
, p. 3002 - 3012 (2020/03/10)
The rapid growth in the global energy demand for space cooling requires the development of more efficient environmental chillers for which adsorption-based cooling systems can be utilized. Here, in this contribution, we explore sorbents for chiller use via a pore-engineering concept to construct analogs of the 1-dimensional pore metal-organic framework MOF-74 by using elongated organic linkers and stereochemistry control. The prepared pore-engineered MOFs show remarkable equilibrium adsorption of the selected fluorocarbon refrigerant that is translated to a modeled adsorption-based refrigeration cycle. To probe molecular level interactions at the origin of these unique adsorption properties for this series of Ni-MOFs, we combined in situ synchrotron X-ray powder diffraction, neutron powder diffraction, X-ray absorption spectroscopy, calorimetry, Fourier transform infrared techniques, and molecular simulations. Our results reveal the coordination of fluorine (of CH2F in R134a) to the nickel(II) open metal centers at low pressures for each Ni-MOF analog and provide insight into the pore filling mechanism for the full range of the adsorption isotherms. The newly designed Ni-TPM demonstrates exceptional R134a adsorption uptake compared to its parent microporous Ni-MOF-74 due to larger engineered pore size/volume. The application of this adsorption performance toward established chiller conditions yields a working capacity increase for Ni-TPM of about 400% from that of Ni-MOF-74, which combined with kinetics directly correlates to both a higher coefficient of performance and a higher average cooling capacity generated in a modeled chiller.
Self-Generation of Surface Roughness by Low-Surface-Energy Alkyl Chains for Highly Stable Superhydrophobic/Superoleophilic MOFs with Multiple Functionalities
Zhu, Neng-Xiu,Wei, Zhang-Wen,Chen, Cheng-Xia,Wang, Dawei,Cao, Chen-Chen,Qiu, Qian-Feng,Jiang, Ji-Jun,Wang, Hai-Ping,Su, Cheng-Yong
, p. 17033 - 17040 (2019/11/11)
We transformed the hydrophilic metal–organic framework (MOF) UiO-67 into hydrophobic UiO-67-Rs (R=alkyl) by introducing alkyl chains into organic linkers, which not only protected hydrophilic Zr6O8 clusters to make the MOF interspace
Temperature-Controlled Evolution of Nanoporous MOF Crystallites into Hierarchically Porous Superstructures
Feng, Liang,Li, Jia-Luo,Day, Gregory S.,Lv, Xiu-Liang,Zhou, Hong-Cai
, p. 1265 - 1274 (2019/05/07)
Sophisticated multichannel tubular structures have long been utilized in biological systems. However, the well-controlled assembly of biomimetic materials utilizing these features still remains a challenge. Herein, we report an unexpected one-pot fabrication of biomimetic hierarchically porous metal-organic framework (MOF) tubular superstructures. This temperature-controlled structural evolution was investigated under solvothermal conditions: crystalline hollow MOF tubes can be obtained via self-templating and self-healing at higher temperatures, whereas hierarchical helical or multichannel tubular superstructures are fabricated through a helical or oriented evolution process at lower temperatures. Our work here presents the first example of tubular MOF superstructures and highlights the unexpected power of self-assembly and healing during structural evolution process. It has been widely observed in various scales that complex systems have a hierarchical or multilevel organization. For instance, hierarchical tubular structures are commonly adopted in natural systems, including bears and bamboo, as a result of long-term evolution, which can help enhance fluid transportation in plants, reduce the overall weight of animals, and prevent heat transfer. Our discovery here mimics the natural evolution and generates a series of hierarchically porous metal-organic framework (MOF) superstructures through self-templating, self-healing, and oriented evolution. This facile strategy provides fresh insights into MOF growth and oriented evolution mechanisms, enabling the state-of-the-art design of multichannel materials with promising applications in water harvesting and transport, multicomponent drug delivery, efficient catalysis, and fabrication of multichannel carbon rods for energy storage. Hierarchically porous superstructures have been successfully assembled from nanoporous MOF crystallites. Benefiting from the dynamic coordination bond formation, hierarchical helical or multichannel tubular superstructures can be accessed through oriented assembly of MOF crystallites. This temperature-controlled structural evolution also enables the formation of crystalline hollow MOF tubes via self-templating and self-healing processes. Further incorporation of multiple components into these frameworks provides a fresh route for preparing stable, multivariate, and hierarchical frameworks with accessible catalytically active sites for heterogeneous catalysis.
Pore-Engineered Metal-Organic Frameworks with Excellent Adsorption of Water and Fluorocarbon Refrigerant for Cooling Applications
Zheng, Jian,Vemuri, Rama S.,Estevez, Luis,Koech, Phillip K.,Varga, Tamas,Camaioni, Donald M.,Blake, Thomas A.,McGrail, B. Peter,Motkuri, Radha Kishan
, p. 10601 - 10604 (2017/08/15)
Metal-organic frameworks (MOFs) have shown promising behavior for adsorption cooling applications. Using organic ligands with 1, 2, and 3 phenylene rings, we construct moisture-stable Ni-MOF-74 members with adjustable pore apertures, which exhibit excelle
METAL-ORGANIC FRAMEWORKS WITH EXCEPTIONALLY LARGE PORE APERATURES
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, (2013/04/24)
The disclosure relates to metal organic frameworks or isoreticular metal organic frameworks, methods of production thereof, and methods of use thereof.
MOLECULAR GAUGE BLOCKS FOR BUILDING ON THE NANOSCALE
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, (2013/05/22)
Disclosed herein is a way to produce a series of discrete sized slender, rigid oligoparaxylene molecules ranging from 1-5 nm in length. Molecules, based on 1-7, 9-11 paraxylene rings, have been synthesized as part of a homologous series of oligoparaxylenes (OPXs) with a view to providing a molecular tool box for the construction of nano architectures—such as spheres, cages, capsules, metal-organic frameworks (MOFs), metal-organic polyhedrons (MOPs) and covalent-organic frameworks (COFs), to name but a few—of well-defined sizes and shapes. Twisting between the planes of contiguous paraxylene rings is generated by the steric hindrance associated with the methyl groups and leads to the existence of soluble molecular gauge blocks without the need—at least in the case of the lower homologues—to introduce long aliphatic side chains onto the phenylene rings in the molecules.
Molecular gauge blocks for building on the nanoscale
Grunder, Sergio,Valente, Cory,Whalley, Adam C.,Sampath, Srinivasan,Portmann, Jürg,Botros, Youssry Y.,Stoddart, J. Fraser
, p. 15632 - 15649 (2013/01/16)
Molecular gauge blocks, based on 1-7, 9-11 paraxylene rings, have been synthesized as part of a homologous series of oligoparaxylenes (OPXs) with a view to providing a molecular tool box for the construction of nano architectures-such as spheres, cages, capsules, metal-organic frameworks (MOFs), metal-organic polyhedrons (MOPs) and covalent-organic frameworks (COFs), to name but a few-of well-defined sizes and shapes. Twisting between the planes of contiguous paraxylene rings is generated by the steric hindrance associated with the methyl groups and leads to the existence of soluble molecular gauge blocks without the need, at least in the case of the lower homologues, to introduce long aliphatic side chains onto the phenylene rings in the molecules. Although soluble molecular gauge blocks with up to seven consecutive benzenoid rings have been prepared employing repeating paraxylene units, in the case of the higher homologues it becomes necessary to introduce hexyl groups instead of methyl groups onto selected phenylene rings to maintain solubility. A hexyl-doped compound with seven substituted phenylene rings was found to be an organogelator, exhibiting thermally reversible gelation and a critical gelation concentration of 10 mM in dimethyl sulfoxide. Furthermore, control over the morphology of a series of hexyl-doped OPXs to give microfibers, microaggregates, or nanofibers, was observed as a function of their lengths according to images obtained by scanning electron microscopy. The modular syntheses of the paraphenylene derivatives rely heavily on Suzuki-Miyaura cross-coupling reactions. The lack of π-π conjugation in these derivatives that is responsible for their enhanced solubilities was corroborated by UV/Vis and fluorescent spectroscopy. In one particular series of model OPXs, dynamic 1H NMR spectroscopy was used to probe the stereochemical consequences of having from one up to five axes of chirality present in the same molecule. The Losanitsch sequence for the compounds with 1-3 chiral axes was established, and a contemporary mathematical way was found to describe the sequence. The development of the ways and means to make molecular gauge building blocks will have positive repercussions on the control of nanostructures in general. Their incorporation into extended structures with the MOF-74 topology provides an excellent demonstration of the potential usefulness of these molecular gauge blocks. Walking along a fine line: The synthesis and characterization of a series of high-aspect-ratio oligoparaxylenes as molecular gauge blocks are reported. The lengths of the molecules range from 10 A? for the shortest member of the series with two phenylene rings up to 50 A? for the longest member with eleven phenylene units (see figure). Minimalistic design criteria led to a walk along a fine line between keeping the molecules slender, yet also rendering them soluble. Copyright
