Core-Shell Crystals of Porous Organic Cages.
Ontology highlight
ABSTRACT:
SUBMITTER: Jiang S
PROVIDER: S-EPMC6120484 | biostudies-literature | 2018 Aug
REPOSITORIES: biostudies-literature
Publications
Core-Shell Crystals of Porous Organic Cages.
Jiang Shan S Du Yi Y Marcello Marco M Corcoran Edward W EW Calabro David C DC Chong Samantha Y SY Chen Linjiang L Clowes Rob R Hasell Tom T Cooper Andrew I AI
Angewandte Chemie (International ed. in English) 20180610 35
The first examples of core-shell porous molecular crystals are described. The physical properties of the core-shell crystals, such as surface hydrophobicity, CO<sub>2</sub> /CH<sub>4</sub> selectivity, are controlled by the chemical composition of the shell. This shows that porous core-shell molecular crystals can exhibit synergistic properties that out-perform materials built from the individual, constituent molecules. ...[more]
Similar Datasets
Project description:In this study, a series of AgCl/ZnO-loaded nanofibrous membranes were prepared using coaxial electrospinning. Their physical and chemical characteristics were evaluated by SEM, TEM, XRD, XPS, IR, PL, and UV-visible spectrometer, and the photocatalytic experiments using methylene blue (MB) as a model pollutant. The formation of AgCl/ZnO heterojunction and the structure of core-shell nanofibers with porous shell layer were confirmed. AgCl/ZnO photocatalysts were also effectively loaded onto the surfaces of the porous core-shell nanofibers. The results of photocatalytic experiments revealed that the AgCl/ZnO (MAgCl:MZnO = 5:5)-loaded nanofibrous membrane achieved a degradation efficiency of 98% in just 70 min and maintained a photocatalytic efficiency exceeding 95% over the first five experimental cycles, which successfully addressed the issues of photocatalytic efficiency loss during the photodegradation of MB with AgCl/ZnO nanoparticles as photocatalyst. The photodegradation mechanism was also researched and proposed.
| S-EPMC10975244 | biostudies-literature
Project description:Although porous organic cages (POCs), particularly imine-linked (C[double bond, length as m-dash]N) ones, have advanced significantly over the last few decades, the reversible nature of imine linkages makes them prone to hydrolysis and structural collapse, severely limiting their applications under moist or water conditions. Herein, seven water-stable hydrazone-linked (C[double bond, length as m-dash]N-N) POCs are prepared through a simple coupling of the same supramolecular tetraformylresorcin[4]arene cavitand with different dihydrazide linkers. Their structures are all determined by single-crystal X-ray crystallography, demonstrating rich structural diversity from the [2 + 4] lantern, [3 + 6] triangular prism, and unprecedented [4 + 8] square prism to the extra-large [6 + 12] octahedron. In addition, they respectively exhibit tunable window diameters and cavity volumes ranging from about 5.4 to 11.1 nm and 580 to 6800 Å3. Moreover, their application in the water environment for pollutant removal was explored, indicating that they can effectively eliminate various types of contaminants from water, including radionuclide waste, toxic heavy metal ions, and organic micropollutants. This work demonstrates a convenient method for rationally constructing versatile robust POCs and presents their great application potentialities in water medium.
| S-EPMC8528071 | biostudies-literature
Project description:Nature has protein channels (e.g., aquaporins) that preferentially transport water molecules while rejecting even the smallest hydrated ions. Aspirations to create robust synthetic counterparts have led to the development of a few one-dimensional channels. However, replicating the performance of the protein channels in these synthetic water channels remains a challenge. In addition, the dimensionality of the synthetic water channels also imposes engineering difficulties to align them in membranes. Here we show that zero-dimensional porous organic cages (POCs) with nanoscale pores can effectively reject small cations and anions while allowing fast water permeation (ca. 109 water molecules per second) on the same magnitude as that of aquaporins. Water molecules are found to preferentially flow in single-file, branched chains within the POCs. This work widens the choice of water channel morphologies for water desalination applications.
| S-EPMC7530991 | biostudies-literature
Project description:A series of porous organic cages is examined for the selective adsorption of sulfur hexafluoride (SF6) over nitrogen. Despite lacking any metal sites, a porous cage, CC3, shows the highest SF6/N2 selectivity reported for any material at ambient temperature and pressure, which translates to real separations in a gas breakthrough column. The SF6 uptake of these materials is considerably higher than would be expected from the static pore structures. The location of SF6 within these materials is elucidated by X-ray crystallography, and it is shown that cooperative diffusion and structural rearrangements in these molecular crystals can rationalize their superior SF6/N2 selectivity.
| S-EPMC5101576 | biostudies-literature
Project description:Using variable temperature 2 H static NMR spectra and 13 C spin-lattice relaxation times (T1 ), we show that two different porous organic cages with tubular architectures are ultra-fast molecular rotors. The central para-phenylene rings that frame the "windows" to the cage voids display very rapid rotational rates of the order of 1.2-8×106 ?Hz at 230?K with low activation energy barriers in the 12-18?kJ?mol-1 range. These cages act as hosts to iodine guest molecules, which dramatically slows down the rotational rates of the phenylene groups (5-10×104 ?Hz at 230?K), demonstrating potential use in applications that require molecular capture and release.
| S-EPMC5813266 | biostudies-literature
Project description:Diverse strategies for the preparation of mixed-metal three-dimensional porous solids abound, although many of them lend themselves only moderate levels of tunability. Herein, we report the design and synthesis of surface functionalized permanently microporous coordination cages and their use in the isolation of mixed metal solids. Judicious alkoxide-based ligand functionalization was utilized to tune the solubility of starting copper(ii)-based cages and their resulting compatibility with the mixed-cage approach described here. We further prepared a family of isostructural molybdenum(ii) cages for a subset of the ligands. The preparation of mixed-metal cage solids proceeds under facile conditions where solutions of parent cages are mixed and product phases isolated. A suite of spectroscopic and characterization tools confirm the starting cages are intact in the amorphous product. Finally, we show that utilization of precise ligand functional groups can be used to prepare mixed cage solids that can be easily and cleanly separated into their constituent components through simple solvent washing or solvent extraction techniques.
| S-EPMC8163318 | biostudies-literature
Project description:We report the first experimental investigation of porous organic cages (POCs) for the demanding challenge of SO2 capture. Three structurally related N-containing cage molecular materials were studied. An imine-functionalized POC (CC3) showed modest and reversible SO2 capture, while a secondary-amine POC (RCC3) exhibited high but irreversible SO2 capture. A tertiary amine POC (6FT-RCC3) demonstrated very high SO2 capture (13.78 mmol g-1 ; 16.4 SO2 molecules per cage) combined with excellent reversibility for at least 50 adsorption-desorption cycles. The adsorption behavior was investigated by FTIR spectroscopy, 13 C CP-MAS NMR experiments, and computational calculations.
| S-EPMC8361948 | biostudies-literature
Project description:The formation of two-dimensional (2D) oriented porous organic cage crystals (consisting of imine-based tetrahedral molecules) on various substrates (such as silicon wafers and glass) by solution-processing is reported. Insight into the crystallinity, preferred orientation, and cage crystal growth was obtained by experimental and computational techniques. For the first time, structural defects in porous molecular materials were observed directly and the defect concentration could be correlated with crystal growth rate. These oriented crystals suggest potential for future applications, such as solution-processable molecular crystalline 2D membranes for molecular separations.
| S-EPMC5577517 | biostudies-literature
Project description:The chemical and structural space of possible molecular materials is enormous, as they can, in principle, be built from any combination of organic building blocks. Here we have developed an evolutionary algorithm (EA) that can assist in the efficient exploration of chemical space for molecular materials, helping to guide synthesis to materials with promising applications. We demonstrate the utility of our EA to porous organic cages, predicting both promising targets and identifying the chemical features that emerge as important for a cage to be shape persistent or to adopt a particular cavity size. We identify that shape persistent cages require a low percentage of rotatable bonds in their precursors (<20%) and that the higher topicity building block in particular should use double bonds for rigidity. We can use the EA to explore what size ranges for precursors are required for achieving a given pore size in a cage and show that 16 Å pores, which are absent in the literature, should be synthetically achievable. Our EA implementation is adaptable and easily extendable, not only to target specific properties of porous organic cages, such as optimal encapsulants or molecular separation materials, but also to any easily calculable property of other molecular materials.
| S-EPMC6251339 | biostudies-literature
Project description:How molecules pack has vital ramifications for their applications as functional molecular materials. Small changes in a molecule's functionality can lead to large, non-intuitive, changes in their global solid-state packing, resulting in difficulty in targeted design. Predicting the crystal structure of organic molecules from only their molecular structure is a well-known problem plaguing crystal engineering. Although relevant to the properties of many organic molecules, the packing behaviour of modular porous materials, such as porous organic cages (POCs), greatly impacts the properties of the material. We present a novel way of predicting the solid-state phase behaviour of POCs by using a simplistic model containing the dominant degrees of freedom driving crystalline phase formation. We employ coarse-grained simulations to systematically study how chemical functionality of pseudo-octahedral cages can be used to manipulate the solid-state phase formation of POCs. Our results support those of experimentally reported structures, showing that for cages which pack via their windows forming a porous network, only one phase is formed, whereas when cages pack via their windows and arenes, the phase behaviour is more complex. While presenting a lower computational cost route for predicting molecular crystal packing, coarse-grained models also allow for the development of design rules which we start to formulate through our results.
| S-EPMC9683088 | biostudies-literature