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Supramolecular lattice assemblies between the cationic Al24 host and a variety of guests a The Al8 macrocyclic subunits adapt to the accommodated H2O (in AlMC-1), NO3⁻ (in AlMC-1), I⁻ (in AlMC-6), Br⁻ (in AlMC-5), Cl⁻ (in AlMC-4), OⁿPr⁻ (in AlMC-2) and OEt⁻ (in AlMC-3) guests. The blue dotted lines indicate that there are strong hydrogen bond interactions between two atoms (the details of the hydrogen bond interactions are provided in Supplementary Figs. 20–25). b Packing diagrams of AlMC-1–AlMC-8. Hydrogen-bond interactions between neighboring Al24 units are shown with yellow dotted lines. (NO3– macrocyclic cavities: pink; alcohol/alkoxide macrocyclic cavities: blue; halogen ion macrocyclic cavities: yellow). The molecular formulae of AlMC-1–AlMC-8 are, respectively: Al24·4NO3–·2HOEt·2H2O (AlMC-1), Al24·4NO3⁻·4HOⁿPr (AlMC-2), Al24·2NO3–·4HOEt·2OEt– (AlMC-3), Al24·NO3–·3Cl⁻ (AlMC-4), Al24·NO3–·3Br– (AlMC-5), Al24·4I– (AlMC-6), Al24·HNO3·6OEt–·(Al6(BA)6(OEt)6(NO3)2)0.5 (AlMC-7), Al24·NO3–·2Br⁻·OEt– (AlMC-8) (Al: bright green; O: red; C: gray; H: white; N: blue; Cl: sea green; Br: purple; I: pink).
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In this paper, we report a unique type of core-shell crystalline material that combines an inorganic zeolitic cage structure with a macrocyclic host arrangement and that can remove trace levels of iodine from water effectively. These unique assemblies are made up of an inorganic Archimedean truncatedhexahedron (tcu) polyhedron in the kernel which p...
Citations
... Among them, radioactive iodine (I 2 ) has high mobility in most geological environments, and its isotopes have a unique exposure problem [9,10]. 129 I isotope is long-lived with a half-life of 1.6 x10 7 years, which must be reliably captured and stored during the decay process [11,12]; while 131 I is a very short-lived isotope with a half-life of 8.02 days, but it needs to be captured immediately, because it directly affects the metabolic process of the human body, especially, thyroid gland [13,14]. Therefore, the development of functional materials for effective control of radioactive iodine vapor emissions is of great significance. ...
... As an alternative, NMR is a unique and powerful technique that provide some dynamic behavior in solution. 54,55 Hence, 1 H NMR experiments of Ti2 and Ti16 were conducted. The 1 H NMR spectrum of Ti2 exhibits peaks at 6.10-6.14 ...
The controlled synthesis of titanium-oxo clusters (TOCs) completely stabilized by organic dye ligands with high stability and superior light absorption remains a significant challenge. In this study, we report the syntheses of three atomically precise catechol (Cat)-functionalized TOCs, [Ti 2 (Cat) 2 (OEgO) 2 (OEgOH) 2 ] (Ti2), [Ti 8 O 5 (Cat) 9 (i PrO) 4 (i PrOH) 2 ] (Ti8), and [Ti 16 O 8 (OH) 8 (Cat) 20 ]·H 2 O·PhMe (Ti16), using a solvent-induced strategy (HOEgOH = ethylene glycol; i PrOH = isopropanol; PhMe = toluene). Interestingly, the TiO core of Ti16 is almost entirely enveloped by catechol ligands, making it the first all-catechol-protected high-nuclearity TOC. In contrast, Ti2 and Ti8 have four weakly coordinated ethylene glycol ligands and six weakly coordinated i PrOH ligands, respectively, in addition to the catechol ligands. Ti16 is visually evident in its distinctively black appearance, which belongs to black TOCs (B-TOCs) and exhibits an ultralow optical band gap. Furthermore, Ti16 displays exceptional stability in various mediums/environments, including exposure to air, solvents, and both acidic and alkaline aqueous solutions due to its comprehensive protection by catechol ligands and rich intra-cluster supramolecular interactions. Ti16 has superior photoelectric response qualities and photothermal conversion capabilities compared to Ti2 and Ti8 due to its ultralow optical band gap and remarkable stability. This discovery not only represents a huge step forward in the creation of all-catecholate-protected B-TOCs with ultralow optical band gap and outstanding stability, but it also gives key valuable mechanistic insights into their photothermal/electric applications.
... Accordingly, various types of adsorbents, including zeolites, aerogels, metal-organic frameworks (MOFs), covalent organic frameworks (COFs) and porous organic polymers (POPs) have been studied for iodine capture [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] . Recently, discrete molecular cages or macrocycles have emerged as promising alternatives as iodine adsorbents [20][21][22][23][24][25][26][27] . For example, nitrogen-rich bipyridine-based organic cages are reported with high iodine capture capacity 24,25 . ...
... Placing 5 mg of water-insoluble 3·6PF 6 into an aqueous solution 26 of I 2 /KI (0.4 mM, 3 mL) caused rapid solution color fading from yellow to colorless ( Supplementary Fig. 55). Time-dependent UV/vis spectroscopy revealed that the removal efficiency of iodine reached up to > 99% in only one minute in the presence of 3·6PF 6 , which is much faster than most adsorbents for iodine removal from water 25,26,61,62 , and 3·6PF 6 exhibited an adsorption capacity of 1.10 ± 0.17 g g −1 from an aqueous solution of I 2 /KI, indicating its great potential for removing iodine from aqueous phase (Supplementary methods 1.3 Iodine uptake experiments from solution). ...
Developing efficient adsorbents to capture radioactive iodine produced from nuclear wastes is highly desired. Here we report the facial synthesis of a hexacationic imidazolium organic cage and its iodine adsorption properties. Crucial role of counteranions has been disclosed for iodine capture with this cage, where distinct iodine capture behaviors were observed when different counteranions were used. Mechanistic investigations, especially with the X-ray crystallographic analysis of the iodine-loaded sample, allowed the direct visualization of the iodine binding modes at the molecular level. A network of multiple non-covalent interactions including hydrogen bonds, halogen bonds, anion···π interactions, electrostatic interaction between polyiodides and the hexacationic skeleton of the cage are found responsible for the observed high iodine capture performance. Our results may provide an alternative strategy to design efficient iodine adsorbents.
... Most of such adsorption materials, more often than not, are reported to be porous sorbents including porous amorphous materials and porous crystalline materials (Fig. 1a, b) 7,8,11 . For instance, porous activated carbon and zeolites alike are the most commonly used adsorbents for trapping iodine because of their low cost, easy availability, and strong affinity 7,[13][14][15] . Nevertheless, such conventional adsorbents are still far from ideal due in large part to their unsatisfying performance in iodine capture (e.g., relatively low iodine loading capacity), inter alia, in aqueous solutions. ...
... The homogeneous iodine distribution in the cage solids was further ascertained by EDS mapping (Fig. 3c and Supplementary Figs. [12][13][14]. Detailed iodine sorption mechanism was initially evaluated by FTIR spectroscopic analysis. IR spectrum of I 2 @SUPE-py-Imine-Cage revealed that the characteristic peaks at~1675, 1601 (and 1527) cm −1 attributed to the C=O and C=N vibration modes of the carbonyl and pyridinyl units shifted to~1652, 1597 (and 1525), respectively (Supplementary Fig. 15a). ...
... 83-84). Likewise, the I 3 − removal efficiency for SUPE-py-Imine-Cage was measured to be~100% in the range of pH 3-14 and that for SUPE-py-Amine-Cage was calculated to be >93% over a wide pH range (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) (Supplementary Fig. 85). In contrast, the iodine uptake capability for ACs was calculated to be between~44% in the range of pH 3-5 and only~34% at pH 7-14 ( Supplementary Fig. 85). ...
Adsorbents widely utilized for environmental remediation, water purification, and gas storage have been usually reported to be either porous or crystalline materials. In this contribution, we report the synthesis of two covalent organic superphane cages, that are utilized as the nonporous amorphous superadsorbents for aqueous iodine adsorption with the record–breaking iodine adsorption capability and selectivity. In the static adsorption system, the cages exhibit iodine uptake capacity of up to 8.41 g g⁻¹ in I2 aqueous solution and 9.01 g g⁻¹ in I3⁻ (KI/I2) aqueous solution, respectively, even in the presence of a large excess of competing anions. In the dynamic flow-through experiment, the aqueous iodine adsorption capability for I2 and I3⁻ can reach up to 3.59 and 5.79 g g⁻¹, respectively. Moreover, these two superphane cages are able to remove trace iodine in aqueous media from ppm level (5.0 ppm) down to ppb level concentration (as low as 11 ppb). Based on a binding–induced adsorption mechanism, such nonporous amorphous molecular materials prove superior to all existing porous adsorbents. This study can open up a new avenue for development of state–of–the–art adsorption materials for practical uses with conceptionally new nonporous amorphous superadsorbents (NAS).
An adjustable template effect was employed to activate the evolution of polyoxovanadate-based metal–organic clusters, resulting in unprecedented structural archetypes as well as customized dye and iodine adsorption features.
Efficient capture and storage of radioactive I2 is a prerequisite for developing nuclear power but remains a challenge. Here, two flexible Ag-MOFs (FJI-H39 and 40) with similar active sites but different pore sizes and flexibility are prepared; both of them can capture I2 with excellent removal efficiencies and high adsorption capacities. Due to the more flexible pores, FJI-H39 not only possesses the record-high I2 storage density among all the reported MOFs but also displays a very fast adsorption kinetic (124 times faster than FJI-H40), while their desorption kinetics are comparable. Mechanistic studies show that FJI-H39 can undergo induced-fit transformations continuously (first contraction then expansion), making the adsorbed iodine species enrich near the Ag(I) nodes quickly and orderly, from discrete I- anion to the dense packing of various iodine species, achieving the very fast adsorption kinetic and the record-high storage density simultaneously. However, no significant structural transformations caused by the adsorbed iodine are observed in FJI-H40. In addition, FJI-H39 has excellent stability/recyclability/obtainability, making it a practical adsorbent for radioactive I2 . This work provides a useful method for synthesizing practical radioactive I2 adsorbents.
