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The solution chemistry of aluminum is highly complex and various polyoxocations are known. Here we report on the facile synthesis of a cationic Al24 cluster that forms porous salts of composition [Al24(OH)56(CH3COO)12]X4, denoted CAU‐55‐X, with X=Cl−, Br−, I−, HSO4−. Three‐dimensional electron diffraction was employed to determine the crystal structures. Various robust and mild synthesis routes for the chloride salt [Al24(OH)56(CH3COO)12]Cl4 in water were established resulting in high yields (>95 %, 215 g per batch) within minutes. Specific surface areas and H2O capacities with maximum values of up to 930 m2 g−1 and 430 mg g−1 are observed. The particle size of CAU‐55‐X can be tuned between 140 nm and 1250 nm, permitting its synthesis as stable dispersions or as highly crystalline powders. The positive surface charge of the particles, allow fast and effective adsorption of anionic dye molecules and adsorption of poly‐ and perfluoroalkyl substances (PFAS). [ABSTRACT FROM AUTHOR]

15 Loiseau, T., Serre, C., Huguenard, C., Fink, G., Taulelle, F., Henry, M., Bataille, T., Férey, G. Chem. Eur. J. 2004, 10, 1373-1382; https://doi.org/10.1002/chem.200305413. 26 Li, W.-J., Liu, J., Sun, Z.-H., Liu, T.-F., Lü, J., Gao, S.-Y., He, C., Cao, R., Luo, J.-H. Nat. 6 García-Sánchez, A., Gomez-Mendoza, M., Barawi, M., Villar-Garcia, I. J., Liras, M., Gándara, F., de la Peña O'Shea, V. A. J. Am. Chem. Soc. 2020, 142, 318-326; https://doi.org/10.1021/jacs.9b10261. 5 Lamagni, P., Miola, M., Catalano, J., Hvid, M. S., Mamakhel, M. A. H., Christensen, M., Madsen, M. R., Jeppesen, H. S., Hu, X.-M., Daasbjerg, K., Skrydstrup, T., Lock, N. Adv. Funct. [Extracted from the article]

Two novel dopant-free hole-transport materials (HTMs) with spiro[dibenzo[c,h]xanthene-7,9′-fluorene] (SDBXF) skeletons were prepared via facile synthesis routes. A power conversion efficiency of 15.9% in perovskite solar cells is attained by using one HTM without dopants, which is much higher than undoped Spiro-OMeTAD-based devices (10.8%). The crystal structures of both new HTMs were systematically investigated to reveal the reasons behind such differences in performance and to indicate the design principles of more advanced HTMs. [ABSTRACT FROM AUTHOR]

Very few microporous bismuth metal‐organic frameworks have been discovered to date. Of these, no detailed experimental characterization of the synthesis and properties have been reported until now for the only one which can be prepared from inexpensive starting materials: CAU‐17 [Bi(BTC)(H2O)], with H3BTC = trimesic acid. In‐situ powder X‐ray diffraction during solvothermal synthesis of CAU‐17 revealed that it crystallizes rapidly within 2 minutes, and if the reaction is not stopped, the MOF transforms into a nonporous dense purely inorganic material within one hour, revealing that CAU‐17 is a crystalline intermediate phase. Synthesis scale‐up employing more concentrated reaction mixtures resulted in another Bi trimesate of composition [Bi(HBTC)(NO3)(MeOH)]·MeOH, which structurally decomposes upon storage under ambient conditions. Sorption experiments showed that CAU‐17 is microporous with a BET surface area of 530 m2/g. As a potential greenhouse gas sorbent, CAU‐17 showed high SF6/N2 and CO2/N2 selectivity > 31 and 29, respectively. Furthermore, the catalytic activity of CAU‐17 was studied in the regioselective ring‐opening of styrene oxide by methanol to obtain 2‐methoxy‐2‐phenylethanol, thus demonstrating the existence of coordinatively unsaturated sites in the crystal structure of CAU‐17. [ABSTRACT FROM AUTHOR]

Three new In-MOFs with –NH2 and/or –NO2 functionalities are reported using 2-amino- (H2BDC-NH2), 2-nitro- (H2BDC-NO2) and 2-amino-5-nitroterephthalic acid (H2BDC-NH2/NO2). Their structures were determined from single crystal X-ray diffraction data. The structure of the first In-MOF of composition [In(BDC-NH3)(BDC-NH2)]·1.6DMF·1.9H2O (In-BDC-NH2; DMF is dimethylformamide; the space group is P6222, a = b = 14.738(2) Å and c = 12.257(3) Å) is built up by two interpenetrating nets of InO8 polyhedra interconnected by BDC-NH22− ions to form a framework with qtz topology. Charge balance is accomplished by partial protonation of the amino group, which was confirmed by IR spectroscopy. The interpenetration leads to a decrease of the pore dimension (4.4 Å in diameter). Thermogravimetric analysis revealed stability up to 300 °C. Replacement of H2BDC-NH2 by H2BDC-NO2 in the reaction mixture led to the isoreticular MOF containing no –NO2 groups but exclusively un- and amino-functionalized linkers. Hence an indium mediated reduction of the H2BDC-NO2 linker molecule during solvothermal synthesis has occurred. The use of H2BDC-NH2/NO2 under exactly the same reaction conditions did not result in the formation of a MOF, but by changing the synthesis parameters, a new –NH2/–NO2 bifunctionalised In-MOF of composition (DMA)2[In3(μ3-O)(BDC-NH2/NO2)4.5]·DMF (DMA is dimethylammonium), denoted In-BDC-NH2/NO2, was obtained. The crystal morphology can be altered from cubic to truncated octahedral crystals by varying the DMF/ethanol volume ratio during synthesis. The compound crystallises in the cubic space group I4̅3m, a = 24.8947(1) Å, and the framework contains trinuclear {In3(μ3-O)} clusters which are interlinked by the BDC-NH2/NO22− ions to form super-tetrahedra. Four face-sharing super-tetrahedra form ultra-tetrahedra which are connected to form the final cubic framework with an ncb topology and isolated inaccessible pores. [ABSTRACT FROM AUTHOR]

A novel open-framework germanate, |NC2H8∥N2C6H18|[Ge7O14.5F2]·4H2O denoted SU-65 (SU = Stockholm University), with 24-ring channels and a very low framework density of 8.9 Ge atoms per 1000 ų was synthesized under hydro-solvothermal conditions. The framework of SU-65 is built of 5-connected Ge7 clusters decorating the fee net and is a framework orientation isomer to ASU-16. Half of the 8- and 12-rings in ASU-16 are instead 10-rings in SU-65 due to the different orientations of half of the clusters in the crystal structure. Flexibility of the frameworks is also influenced by the orientation of the clusters. The unique unit cell angle in SU-65 changes upon heating, unlike ASU-16 which only undergoes changes in unit cell lengths. SU-65 undergoes significant structural changes at 180 °C in a vacuum, forming SU-65ht. The crystal structure of SU-65ht was investigated by rotation electron diffraction, X-ray powder diffraction, and infrared spectroscopy. Through these techniques it was deduced that SU-65ht has similar clusters, symmetry, and topology as SU-65, but one of the unit cell lengths is shortened by approximately 5 Å. This corresponds to a 22% decrease in unit cell volume. [ABSTRACT FROM AUTHOR]

A bismuth-based metal-organic framework (MOF), [Bi(BTC)(H2O)]·2H2O·MeOH denoted CAU-17, was synthesized and found to have an exceptionally complicated structure with helical Bi-O rods cross-linked by 1,3,5-benzenetricarboxylate (BTC3-) ligands. Five crystallographically independent 1D channels including two hexagonal channels, two rectangular channels, and one triangular channel have accessible diameters of 9.6, 9.6, 3.6, 3.6, and 3.4 Å, respectively. The structure is further complicated by twinning. Rod-incorporated MOF structures typically have underlying nets with only one unique node and three or four unique edges. In contrast, topological analysis of CAU-17 revealed unprecedented complexity for a MOF structure with 54 unique nodes and 135 edges. The complexity originates from the rod packing and the rods themselves, which are related to aperiodic helices. [ABSTRACT FROM AUTHOR]

The crystal structure of a novel open-framework gallogermanate, SU-66 {|(C6H18N2)18(H2O)32|[Ga4.8Ge87.2O208]}, has been solved from laboratory X-ray powder diffraction (XPD) data by using a direct-space structure solution algorithm and local structural information obtained from infrared (IR) spectroscopy. IR studies on 18 known germanates revealed that the bands in their IR spectra were characteristic of the different composite building units (CBUs) present in the structures. By comparing the bands corresponding to Ge-O vibrations in the IR spectra of SU-66 with those of the 18 known structures with different CBUs, the CBU of SU-66 could be identified empirically as the Ge10(O,OH)27 cluster (Ge10). The unit cell and space group (extinction symbol P-- a; a = 14.963, b = 31.593, c = 18.759 Å) were determined initially from the XPD pattern and then confirmed by selected-area electron diffraction. The structure of SU-66 was solved from the XPD data using parallel tempering as implemented in FOX [Favre-Nicolin & Černý (2002). J. Appl. Cryst. 35, 734-743] by assuming P21 ma symmetry and two Ge10 clusters in the asymmetric unit. Rietveld refinement of the resulting structure using synchrotron XPD data showed the framework structure to be correct and the space group to be Pmma. The framework has extra-large (26-ring) one-dimensional channels and a very low framework density of 10.1 Ge/Ga atoms per 1000 Å3. SU-66, with 55 framework atoms in the asymmetric unit, is one of the more complicated framework structures solved from XPD data. Indeed, 98% of the reflections were overlapping in the XPD pattern used for structure solution. Tests on other open-framework germanates (SU-62, SU-65, SU-74, PKU-12 and ITQ-37) for which the XPD data, unit cell, space group and IR spectra were available proved to be equally successful. In a more complex case (SU-72) the combination of FOX and powder charge flipping was required for structure solution. [ABSTRACT FROM AUTHOR]

A novel open-framework silicogermanate SU-JU-14 (StockholmUniversity-JilinUniversity-Number 14), |NH3CH2CH2NH3|3[Ge6.40Si0.60O15(OH)]2[Ge0.73Si3.27O8], was synthesizedby using ethylenediamine as the structure-directing agent under solvothermalconditions. Single-crystal structure analysis reveals that the crystalstructure of SU-JU-14 consists of extended 24-ring channels builtfrom [(Ge,Si)7O12O6/2(OH)]3–[(Ge,Si)7] clusters and unbranched zweiersilica double chains [Ge0.73Si3.27O4O8/2]. Charge neutrality is achieved by diprotonated ethylenediamineguest molecules. The structure consists of stacking faults of layeredarrays in two different configurations along the a-axis. SU-JU-14 was characterized by X-ray diffraction, X-ray energydispersive spectroscopy, scanning electron microscopy, nuclear magneticresonance, inductively coupled plasma, and thermogravimetric analyses.Crystallographic data: monoclinic, space group C2/c, and unit cell parameters: a= 35.625(7) Å, b= 28.580 (6) Å, c= 10.403 (2) Å, and β = 98.30 (3)°. [ABSTRACT FROM AUTHOR]

• Development of three-dimensional electron diffraction (3DED) methods. • Ab initio structure determination of MOFs and COFs using 3DED. • Reveal of structure–property relationships using 3DED. • Accuracy of 3DED methods on structure determination. Metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) have emerged as the most widely investigated classes of porous materials during the past two decades. The almost unlimited combination of building units (metal clusters and organic molecules) endows highly tuneable porosities and functionalities that are appealing for a wide scope of applications. The applications of MOFs and COFs depend on their physical and chemical properties, which in turn are determined by the arrangement of atoms – the crystal structures. Therefore, structure determination is arguably the most important characterization step for MOFs and COFs. While single crystal X-ray diffraction (SCXRD) is the most widely used method for structure determination, many MOFs and COFs are synthesized in too small sizes or their crystal qualities are too low for SCXRD. During recent years, three-dimensional electron diffraction (3DED) methods has undergone rapid developments and can be used for structure determination of nano- and submicro-sized crystals to overcome this fundamental drawback. In this review, we summarize the development of 3DED methods and their applications for structure elucidation of MOFs and COFs. Advances of 3DED data collection techniques are described, from step-wise rotation to continuous rotation of the crystal. The latter allows fast data collection which is crucial for beam sensitive materials including MOFs and COFs. Examples of ab initio structure determination of various MOFs and COFs by using 3DED are presented, with highlighted examples for solving the structures of mesoporous MOFs, mixed-metal MOFs, flexible MOFs, and for studying host–guest interactions. Finally, the accuracy and reproducibility of structure determination by 3DED are presented. We show the structure information obtained from 3DED provides crucial insights into structure–property relationships, which could further accelerate the development of new functional materials. [ABSTRACT FROM AUTHOR]