We present a facile approach to encapsulate functional porous organic cages (POCs) into a robust MOF by an incipient‐wetness impregnation method. Porous cucurbit[6]uril (CB6) cages with high CO2 affinity were successfully encapsulated into the nanospace of Cr‐based MIL‐101 while retaining the crystal framework, morphology, and high stability of MIL‐101. The encapsulated CB6 amount is controllable. Importantly, as the CB6 molecule with intrinsic micropores is smaller than the inner mesopores of MIL‐101, more affinity sites for CO2 are created in the resulting CB6@MIL‐101 composites, leading to enhanced CO2 uptake capacity and CO2/N2, CO2/CH4 separation performance at low pressures. This POC@MOF encapsulation strategy provides a facile route to introduce functional POCs into stable MOFs for various potential applications.
The prolific topic of development of solidstate lighting devices has focused over the last years on solid-state white light (SSWL) emitting materials, mainly due the long operation lifetime and excellent harvesting and saving energy. [1] Even today, incandescent and mercury-based fluorescent materials are employed as white-light sources due to their superior warm-white light impression. Moreover, the fabrication of environmentally safe white light-emitting diode (LEDs) with a "warm-white" impression remains still a challenge. Many of the "white" organic light-emitting diode/ LED materials cover only part of the visible spectrum and lack the required efficacy of 150-200 lm W −1 for white-light performance. [2] For this reason, the design of a new generation of SSWL materials is of continuous interest in materials science, especially in areas such as full-color flat-panel electroluminescent displays for mobile devices, optical telecommunications, lighting, and backlighting for liquid-crystals displays. [3] Besides, high-quality white-light performance requires the Commission International de l'Eclairage (CIE) x,y coordinates 0.333, 0.333, with a correlated color temperature (CCT) into the 2500-6500 K, and color rendering index above 80 which are standard requirements for lighting applications. [4] One of the explored strategies to obtain white light is by combining red, green, and blue (RGB) sources to cover the visible region (400-700 nm) in the electromagnetic spectrum. [5] Also, metal-organic frameworks (MOFs) have been the focus of interest due to their potential applications in gas storage/ separation , [6] catalysis, [7] optics, [8] magnetism, [9] sensing, [10] and biomedicine. [4,11,12] Due to a permanent porosity, structural diversity, functionalization capabilities and then, tunable luminescence, MOF possess interesting properties for the development of SSWL composites. In recent years, a large number of luminescent MOFs have been reported for this purpose. [5,13-24] Moreover, for uses in nanotechnology, it is mandatory that MOFs are anchored on solid substrates, being particularly evident in the case of optoelectronic applications. [25,26] According to specialized reviews such as those from Wöll group, [27] it is distinguishable the surface-supported metal-organic frameworks (SURMOFs) devices, fabricated using layer-by-layer (LbL) A new set of Ln-MOF (lanthanide-metal-organic framework) thin films, known as Ln-SURMOFs (surface-supported MOFs), is fabricated with a layer-by-layer, in order to generate solid-state white-lighting devices. A three-component approach is carried out for a rational combination of red, green, and blue (RGB) emitting Eu 3+ , Tb 3+ , and Gd 3+ containing layers in order to achieve white-light emission. The Ln-SURMOFs are fully characterized by powder X-ray diffraction, infrared reflection-absorption spectroscopy, scanning electron microscopy, and photoluminescence spectroscopy (excitationemission and chromaticity determination according to Commission International de l'Eclairage, C...
The simultaneous determination of halide impurities (fluoride, chloride, bromide, and iodide) and ionic liquid (IL) anions (tetrafluoroborate, hexafluorophosphate, and triflimide) using ion chromatography was developed with a basic, non‐gradient ion chromatography system. The non‐gradient method uses the eluent Na2CO3/NaHCO3 in water/acetonitrile (70:30 v:v) on the AS 22 column to enable a rapid and simultaneous analysis of different IL and halide anions within an acceptable run‐time (22 min) and with good resolution R of larger than 2.4, a capacity k′ between 0.4 and 5.1, selectivities α between 1.3 and 2.1, and peak asymmetries As of less than 1.5. Halide impurities below 1 ppm (1 mg·L–1 of prepared sample solution) could be quantified. A range of ionic liquids with tetrafluoroborate [BF4]–, hexafluorophosphate [PF6]–, and bis(trifluoromethylsulfonyl)imide (triflimide) [NTf2]– anions combined with cations based on imidazole, pyridine, and tetrahydrothiophene could be analyzed for their anion purity. The IL‐cations do not influence the chromatographic results. With the analysis of 18 ILs differing in their cation‐anion combination we could prove the general applicability of the described method for the anion purity analysis of ionic liquids with respect to halide ions. The IL‐anion purity of most ILs was above 98 wt %. The highest IL‐anion purity was 99.8 wt %, implying anion impurities of only 0.2 wt %. The used halide anion from the synthesis route was the major anion impurity, yet with chloride also bromide and fluoride (potentially from hydrolysis of [BF4]–) were often detected. When iodide was used, at least chloride but sometimes also bromide and fluoride was present. However, even if the IL‐anion content is above 99 wt %, it does not necessarily indicate an ionic liquid devoid of other impurities. From the IC analysis, one can also deduce a possible cation impurity if one takes into account the expected (calculated) IL‐anion content. A matching experimental and theoretical IL‐anion content excludes, a higher experimental content indicates the presence of residual KBF4, NH4PF6, or LiNTf2 salt from the halide to IL‐anion exchange.
The first examples of monolithic crystalline hostguest hybrid materials are described. The reaction of 1,3,5benzenetricarboxylic acid (H 3 BTC) and Fe(NO 3 ) 3 •9 H 2 O in the presence of decamethylcucurbit [5]uril ammonium chloride (MC5•2 NH 4 Cl•4 H 2 O) directly affords MC5@MIL-100(Fe) hybrid monoliths featuring hierarchical micro-, meso-and macropores. Particularly, this "bottle-around-ship" synthesis and one-pot shaping are facilitated by a newly discovered Fe-MC5 flowing gel formed by mechanochemistry. The designed MC5@MIL-100(Fe) hybrid material with MC5 as active domains shows enhanced CH 4 and lead(II) uptake performance, and selective capture of lead(II) cations at low concentrations. This shows that host-guest hybrid materials can exhibit synergic properties that out-perform materials based on individual components.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.