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Two new isostructural porous coordination polymers (CPs) were obtained under solvothermal reaction conditions using 2,5‐dihydroxy‐p‐benzoquinone (H2DHBQ) or 1,2,4,5‐tetrahydroxybenzene (H4THB) as linker molecule and Zr4+ or Hf4+ salts. Highly crystalline compounds with composition [M2(μ‐OH)2(DHBQ)3]·xH2O (M = Zr4+ or Hf4+, x = 0–3.6/3.3) were found in a wide temperature range (120–200 °C) and a reaction time of 70 h. The crystal structures were determined ab initio from powder X‐ray diffraction data and the oxidation state of the linker was confirmed spectroscopically. The dinuclear inorganic building unit M2O14 is new for Zr‐ and Hf‐CPs. For both compounds a full characterization was carried out, i.e. crystal structure determination, spectroscopic measurements, elemental‐ and thermogravimetric analyses. [M2(OH)2(DHBQ)3] (M = Zr4+ or Hf4+) is stable up to 250 and 220 °C, respectively. Water sorption measurements proofed an uptake of 3.6 mol H2O per mol and 3.3 mol H2O per mol, respectively. [ABSTRACT FROM AUTHOR]

Here, we have described the design, preparation and detailed characterization of a new acetoxy functionalized aluminium based metal–organic framework (MOF) called CAU-10-OCOCH3 (1) (CAU stands for Christian-Albrechts-University). The desolvated compound was employed for the detection of perborate in a pure aqueous environment. The presented MOF based perborate sensing probe (1) was synthesized by employing 5-acetoxyisophthalic acid and AlCl3·6H2O as the linker molecule and metal salt source, respectively, in DMF/H2O medium at 120 °C for 12 h. The material (1′) showed a very selective fluorescent turn-on response towards perborate in aqueous medium with the coexistence of several competitive analytes. A dramatic increment (65 fold) in emission intensity of the probe was observed within 5 min of the addition of perborate. A chemo-selective reaction between perborate and the acetoxy functionality and subsequent hydrolysis of the acetoxy group to the hydroxy group is the main cause of the turn-on nature of detection. The material showed a detection limit of 1.19 μM. The probe was also applied for the recognition of perborate in several environmental water samples. The material is the first ever MOF based probe for selective detection of perborate. [ABSTRACT FROM AUTHOR]

A new scandium naphthalenedicarboxylate with the framework composition [Sc2(1,4‐NDC)3] (H2‐1,4‐NDC = 1,4‐naphthalenedicarboxylic acid) was obtained under hydrothermal synthesis conditions. A structure model could be developed by a combination of 3D electron diffraction measurements and computationally assisted structure determination, which was further validated by a good agreement with the experimental powder X‐ray diffraction pattern. The structure consists of isolated ScO6 octahedra interconnected by the carboxylate groups of linker molecules to form chains. These chains are connected by the naphthalene‐moieties to form a three‐dimensional framework with square‐shaped pores and the organic group pointing into the pores. Although very similar synthesis conditions were chosen, [Sc2(1,4‐NDC)3] is not isostructural to aluminum naphthalenedicarboxylate [Al(OH)(1,4‐NDC)], which crystallizes in a MIL‐53 type structure. This can be traced back to the different inorganic building units that are observed. The compound was thoroughly characterized by elemental analysis, IR spectroscopy, sorption measurements, thermogravimetric analysis and luminescence measurements. [Sc2(1,4‐NDC)3] exhibits a high thermal stability and a ligand‐based blue luminescence in the solid state at room temperature. [ABSTRACT FROM AUTHOR]

A new scandium metal‐organic framework (MOF) with the composition [Sc(OH)(SDBA)], denoted Sc‐CAU‐11, was synthesized under solvothermal reaction conditions using 4,4‐sulfonyldibenzoic acid (H2SDBA), as a V‐shaped linker molecule. The crystal structure was refined from powder X‐ray diffraction (PXRD) data employing the Rietveld method and using the structural model of the isostructural aluminium compound. Sc‐CAU‐11 crystallizes in the orthorhombic space group Pnma and is composed of chains of trans corner‐sharing ScO6 octahedra. The chains are connected by the linker molecules to form layers with intralayer porosity and an ABAB stacking sequence. Detailed characterization was carried out by elemental analysis, IR‐spectroscopy, thermogravimetric analysis, gas sorption and luminescence measurements. Sc‐CAU‐11 shows a high thermal stability up to 500 °C in air, which is confirmed by temperature‐depended PXRD measurements. The optical properties were tuned by substituting Sc3+ ions in Sc‐CAU‐11 with trivalent europium and terbium ions and strong temperature as well as excitation dependent optical emission is observed. [ABSTRACT FROM AUTHOR]

The new MOF Ga‐MIL‐53‐PDA [Ga(OH)(O2C‐C8H8‐CO2)]·H2O (1) was synthesized by a hydrothermal reaction of gallium nitrate, 1,4‐phenylenediacetic acid (H2PDA) and sodium hydroxide at 100 °C for 24 h. The product is a structural analogue of the archetypical MIL‐53 framework. Its crystal structure was determined by Rietveld refinement of powder X‐ray diffraction (PXRD) data. Furthermore 1,4‐phenylenedipropionic acid (H2PDP) was employed for further synthesis, which resulted in the dense layered coordination polymers [Ga2(OH)4(O2C‐C10H12‐CO2)] (2) and [Ga(OH)(O2C‐C10H12‐CO2)] (3), for which accurate structural models could be established. All compounds were fully characterized and tested regarding potential breathing behavior. Most remarkably, Ga‐MIL‐53‐PDA showed a subtle flexibility upon de/‐rehydration also confirming its porosity, but no drastic structural changes were observed. [ABSTRACT FROM AUTHOR]

The most contracted cerium(IV)-based metal–organic framework (MOF) with fcu topology incorporating an alkyne-based linker, namely acetylenedicarboxylate (ADC), was synthesized under green conditions in water at room temperature and thoroughly characterized. The structure of this new MOF, denoted as Ce-HHU-1, was determined from powder X-ray diffraction data and Rietveld refinement and is made up of octahedral [Ce6O4(OH)4]12+ clusters, each of which is connected to other inorganic units by twelve ADC linkers to give a porous network with fcu topology analogous with UiO-66. The permanent microporosity of Ce-HHU-1 was confirmed by nitrogen sorption, meanwhile its high hydrophilicity was displayed by a type I water vapor sorption isotherm. The adsorption of CO2 in Ce-HHU-1 features a remarkably high zero-coverage isosteric heat of adsorption of 47 kJ mol−1, attributed to the presence of the –C≡C– triple-bond in the framework. The latter also allows for Ce-HHU-1 to capture and irreversibly chemisorb Br2 vapors, as well as both chemi- and physisorb I2 vapors in an effective manner, making this material potentially applicable for air cleaning from toxic halogen vapors. [ABSTRACT FROM AUTHOR]

The new compound {[Cu(cyclam)]2[Sn2S6]}n·2nH2O containing Cu(II) was synthesized at room temperature reacting aqueous solutions of Na4SnS4·14H2O and of [Cu(cyclam)](ClO4)2. A crystalline precipitate consisting of small crystallites was formed after a very short reaction time of 2 h. Structure analysis reveals that [Sn2S6]4– anions are joined by the [Cu(cyclam)]2+ cations via Cu–S bonds generating layers which are stacked along the crystallographic a‐axis. The Cu(II) centers are in a distorted octahedral environment of four N and two S atoms. The distortion is reflected in the EPR spectrum that displays the A∥ lines characteristic for Cu2+ (I = 3/2) and due to g∥ > g⊥ > 2.0023, the unpaired electron is located in the dx2–y2 orbital. The crystal water molecules can be removed at elevated temperatures, while crystallinity of the sample is mainly retained. Storage of the dehydrated sample on air leads to water uptake and recovery of the pristine compound. [ABSTRACT FROM AUTHOR]

A metal–organic framework (MOF) with a Zr(IV) ion containing a 2,3,5,6-tetrakis(4-carboxyphenyl)pyrazine (H4L) ligand was prepared by a solvothermal method. ZrOCl2·8H2O was employed along with the H4L ligand and benzoic acid (modulator) in N,N-dimethylformamide (DMF) to synthesize the title compound. The as-synthesized compound has the formula [Zr6(μ3-O)4(μ3-OH)4(OH)4(H2O)4(L)2]·3H2O·2DMF (1). The activation of 1 was carried out by using methanol exchange and subsequent heating under high vacuum at 130 °C. Both 1 and the activated sample (1′) were characterized by X-ray powder diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). They displayed high chemical stability and thermal stability. Both 1 and 1′ are stable up to 440 °C. Compound 1′ has a very high BET surface area (1419 m2 g−E) and CO2 adsorption capacity (4.4 mmol g−1 at 1.4 bar and 0 °C). Being highly water-stable, luminescent 1′ can selectively recognize Fe3+ and dichromate (Cr2O72−) in water and picric acid (PA) in dimethyl sulfoxide (DMSO), by a fluorescence quenching mechanism. The detection limits were found to be 3.75, 13.08 and 8.58 ppb for Fe3+, PA and Cr2O72−, respectively. Moreover, the mechanisms behind this selective detection of all three analytes were also investigated. In all three cases, the compound showed reusability up to five cycles without any loss of sensing efficacy. These experimental data vividly show that 1′ can be considered as a promising sensing material for Fe3+, PA and Cr2O72−. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) enable the design of host–guest systems with specific properties. In this work, we show how the confinement of anthracene in a well‐chosen MOF host leads to reversible yellow‐to‐purple photoswitching of the fluorescence emission. This behavior has not been observed before for anthracene, either in pure form or adsorbed in other porous hosts. The photoresponse of the host–guest system is caused by the photodimerization of anthracene, which is greatly facilitated by the pore geometry, connectivity, and volume as well as the structural flexibility of the MOF host. The photoswitching behavior was used to fabricate photopatternable and erasable surfaces that, in combination with data encryption and decryption, hold promise in product authentication and secure communication applications. The confinement of anthracene molecules in a metal–organic framework enables reversible yellow‐to‐purple photoswitching of the fluorescence emission. The photoresponse of the host–guest system strongly relies on the unique properties of the MOF host, that is, the pore geometry, connectivity, and volume as well as the structural flexibility. The solid‐state photoswitching enabled the development of photopatternable, erasable, and rewritable paper. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) enable the design of host–guest systems with specific properties. In this work, we show how the confinement of anthracene in a well‐chosen MOF host leads to reversible yellow‐to‐purple photoswitching of the fluorescence emission. This behavior has not been observed before for anthracene, either in pure form or adsorbed in other porous hosts. The photoresponse of the host–guest system is caused by the photodimerization of anthracene, which is greatly facilitated by the pore geometry, connectivity, and volume as well as the structural flexibility of the MOF host. The photoswitching behavior was used to fabricate photopatternable and erasable surfaces that, in combination with data encryption and decryption, hold promise in product authentication and secure communication applications. [ABSTRACT FROM AUTHOR]

Two new metal–organic framework compounds of composition [M12(μ3-O)8(μ3-OH)8(μ-OH)6(OH)6(H2O)6(APDC)6], with M = Zr and Hf, denoted as M-CAU-39, containing the azopyridinedicarboxylate ion (APDC2−) as a new linker, were obtained by a water-based synthesis. The crystal structure was determined from powder X-ray diffraction data. The inorganic building unit (IBU) is the dodecanuclear cluster {M12O8(OH)14} and its connection results in a porous two-dimensional network. [ABSTRACT FROM AUTHOR]

Abstract: A strategy was developed to obtain from acetylenedicarboxylic acid either an acetylenedicarboxylate‐based ZrIV metal–organic framework (MOF) with fcu topology or a halo‐functionalized‐MOF‐801 through in situ ligand hydrohalogenation. The new materials feature exceptionally high hydrophilicity and CO2/H2 adsorption energetics. The acetylenedicarboxylate linker and its functionalizable triple‐bond discloses its potential in the engineering of microporous materials with targeted properties. [ABSTRACT FROM AUTHOR]

Abstract: A new aluminium metal‐organic framework (MOF), based on the short aliphatic linker molecule mesaconic acid (H2Mes; methylfumaric acid) is reported. Al‐MIL‐68‐Mes with composition [Al(OH)(O2C‐C3H4‐CO2)]⋅n H2O is obtained after short reaction times of 45 minutes under mild, aqueous synthesis conditions (95 °C). It exhibits a kagome‐like framework structure with large hexagonal, and small trigonal channels (diameters of ≈6 and ≈2 Å, respectively) and a specific surface area of SBET ≈1040 m2 g−1 (VMIC=0.42 cm3 g−1). A sigmoidal vapour sorption isotherm for water, and uptakes of water and methanol above 30 wt. % were observed. Al‐MIL‐68‐Mes is stable against water ad‐/desorption and its thermal stability is 350 °C in air. The proton conductivity for the hydrated MOF showed values up to 1.1×10−5 S cm at 130 °C and 100 % relative humidity, which exceeds the values observed for the non‐hydrated compound by up to four orders of magnitude. Using synchrotron radiation the crystallisation of the MOF by in situ PXRD was also studied at temperatures from 80 to 100 °C. Kinetic evaluation revealed that the induction periods and crystallization times vary depending on the synthesis batch, but the rate limiting steps are consistently observed. [ABSTRACT FROM AUTHOR]

A new, azide-functionalized Al(iii)-based metal–organic framework (MOF) denoted as CAU-10-N3 (1, CAU = Christian-Albrechts-University) and consisting of the 5-azido-isophthalic acid (H2IPA-N3) ligand was employed as a reaction-based fluorescent turn-on probe for the detection of H2S. The activated compound (1′) showed fast, selective and highly sensitive sensing properties for extracellular H2S in HEPES buffer (10 mM, pH = 7.4). The material retained its high selectivity even in the presence of possibly competing biological species. The limit of detection of 1′ for H2S is 2.65 μM, which is lower than the earlier reports on MOFs for H2S sensing. The material displayed a short response time (420 s) and a significant increase (20-fold and 26-fold after 1 and 7 min of addition of Na2S, respectively) in the fluorescence intensity towards H2S. Macrophage cells loaded with probe 1′ exhibited blue fluorescence with a response time of 15 min after Na2S addition, indicating the suitability of the probe for intracellular H2S detection. Moreover, CAU-10-N3 featured excellent detection performance (quick response and 32-fold increment in fluorescence intensity after 7 min of Na2S addition) in water. Hence, it can be utilized to regulate the H2S level in aqueous samples collected from the environment. [ABSTRACT FROM AUTHOR]

The systematic investigation of the solvothermal system Al 3+ /5-fluoroisophthalic acid (H 2 m BDC-5F)/isophthalic acid (H 2 m BDC)/DMF/H 2 O through a mixed-linker approach led to new mixed-linker CAU-10 derivatives containing 11, 28 and 44% of fluorinated linker molecules (denoted as CAU-10-H/F 11 , CAU-10-H/F 28 and CAU-10-H/F 44 , respectively), as determined by NMR spectroscopy. The crystal structure of CAU-10-H/F 28 was determined using the Rietveld method (space group I 4 1 md , a = b = 21.3075(5), c = 10.7101(3) Å). The structure is built up by helical chains composed of cis corner-sharing AlO 6 polyhedra. Each of these helices is interconnected to four adjacent helices with alternating rotational orientation through the carboxylate groups of m BDC 2- linker molecules. Thus, accessible, square-shaped channels are formed. Sorption measurements revealed a high dependency of the adsorbed amount of gas on the degree of fluorination. With increasing fluorination, the total uptake decreases in N 2 , H 2 and H 2 O sorption experiments and the hydrophobic character of the pores increases. In addition, an extended CAU-10 derivative, CAU-10-HTATB, was discovered using the tricarboxylic acid 4,4′,4″- s -triazine-2,4,6-triyl-tribenzoic acid (H 3 TATB) during the high-throughput investigation of the system Al 3+ /H 3 TATB/DMF/H 2 O. This new MOF, which was denoted CAU-10-HTATB, was thoroughly characterized using IR spectroscopy, thermogravimetric and elemental analysis, temperature dependent powder X-ray diffraction (PXRD) and sorption measurements. Although the compound is thermally stable up to 400 °C according to temperature-dependent PXRD measurements, it is not porous towards N 2 molecules. The structure of CAU-10-HTATB could be also refined from PXRD data using the Rietveld method (space group I 4 1 / a , a = b = 36.438 (1), c = 10.9373 (9) Å). [ABSTRACT FROM AUTHOR]

We report the water-induced transformation of the [Zn2(dobdc)] (dobdc = 2,5-dioxidobenzene-1,4-dicarboxylate) metal–organic framework UTSA-74 to its polymorph MOF-74(Zn), contrary to a previous report on the stability of UTSA-74 under such conditions. This dissolution–recrystallization process was investigated using time-resolved in situ X-ray diffraction and kinetically analyzed using the Gualtieri crystallization model. [ABSTRACT FROM AUTHOR]

This perspective highlights some studies and insights in the synthesis of metal–organic frameworks (MOFs) in a brief and comprehensive manner. The understanding of the synthesis procedures investigated by in and ex situ methods is of special interest since knowledge on the nucleation and crystallisation mechanism will ideally lead to an improved control over product formation. The prospective developments associated with the manufacturing of such materials (or devices consisting thereof) are discussed as well. A major challenge is the adjustment of the synthesis conditions to yield quantities suitable for real life applications. Last but not least, vast opportunities are yet to be explored involving the synthesis of both known and novel compounds. Thus the crucial points involving the synthesis of MOFs summarized in this perspective are rationalisation, application and exploration. For each subtopic we have also attempted to anticipate future challenges and developments. [ABSTRACT FROM AUTHOR]

The title compound AuS2CNH2 was prepared from an aqueous solution by reaction of dicyanidoaurate [Au(CN)2]- with excess of ammoniumdithiocarbamate NH4S2CNH2 at pH ≈ 2. The compound crystallizes in the orthorhombic space group Cmma with a = 6.4597(2), b = 12.6556(3), and c = 5.3235(1) Å. The crystal structure comprises linear S-Au-S dumbbells forming unbranched zigzag chains in combination with the dithiocarbamate ligands. The three-dimensional arrangement of the molecules is realized by aurophilic AuI-AuI and hydrogen bonding interactions, respectively. AuS2CNH2 presents orange luminescence due to a broad emission band between 12000 cm-1 and 23000 cm-1 (v = 26316 cm-1). [ABSTRACT FROM AUTHOR]

The intercalation of different pyrazines (pyrazine, methylpyrazine, 2,5-dimethylpyrazine, 2,3-dimethylpyrazine, trimethylpyrazine and tetramethylpyrazine) into the trans-1,4-cyclohexanedicarboxylate (CDC2−) based Al-MOF [Al(OH)(CDC)], denoted as CAU-13, was investigated. The adsorption of the guest molecules into the flexible MOF was carried out from an aqueous solution or via vapour phase adsorption, starting with the hydrated narrow-pore form of the framework [Al(OH)(O2C-C6H10-CO2)]·H2O (CAU-13-np). The obtained host–guest systems were characterised by thermogravimetry and vibrational spectroscopy and their crystal structures were elucidated using powder X-ray diffraction (PXRD) data. The crystal structures indicate that guest molecules forming hydrogen-bonds with the host framework (pyrazine, methylpyrazine and 2,5-dimethylpyrazine) induce a slight opening of the channels, resulting in a semi-open framework conformation (CAU-13-so). For the bulkier guests 2,3-dimethylpyrazine, trimethylpyrazine and tetramethylpyrazine, only van der Waals interactions can be observed between the host and the guest molecules and a large pore conformation is observed (CAU-13-lp). We carried out in situ PXRD studies using synchrotron radiation during the adsorption of the respective guest molecules from aqueous solutions with various concentrations and at different temperatures. In general, stronger host–guest interactions required milder adsorption conditions while harsher conditions nevertheless accelerated the conversion. The kinetic parameters for the intercalation of pyrazine indicate that the rate limiting step differs, depending on the intercalation temperature. [ABSTRACT FROM AUTHOR]

Two new squarate complexes based on aluminum and gallium, [Al2(OH)2(C4O4)2(H2O)4] ·2H2O ( 1) and [Ga2(OH)2(C4O4)2(H2O)4] ·2H2O ( 2) were hydrothermally synthesized and characterized by infrared spectroscopy and thermogravimetric measurements. The structure of 1 was determined by single-crystal X-ray diffraction and the structure of 2 was refined from PXRD data. The dinuclear squarate complexes consist of two MO6 polyhedra ( M = Al or Ga) interconnected by two squarate ions in axial and two hydroxyl groups in equatorial position. Two water molecules are coordinating to each central metal atom in equatorial position to complete the coordination spheres. Furthermore, a non-coordinating water molecule is located between the dinuclear units. Hydrogen bonding leads to the interconnection of the molecular complexes to a three-dimensional network. [ABSTRACT FROM AUTHOR]

Research in the field of metal-organic frameworks (MOFs) has been for a long time devoted to the synthesis of new compounds and the understanding of their outstanding properties. Just in the recent four or five years there has been an emerging interest in up-scaling of synthesis procedures and the adjustment of synthesis conditions towards industrial requirements. This probably originates from the fact that, while some MOFs are already commercially available, there is still no field of application in real life which MOFs are able to fit in. One reason for this might be the attributed to the common synthetic procedures which are often unsuitable for preparations at pilot or industrial scale. Thus a recent focus in MOF research is the finding of synthesis conditions which employ non-hazardous reactants at relatively mild synthetic conditions, producing also less waste than conventional procedures. In brief: The 'green' synthesis of MOFs. This microreview is intended to give some examples of the efforts made in this field of research and show some perspectives for the future. [ABSTRACT FROM AUTHOR]

Considering the requirements for the commercial production of metal-organic frameworks (MOFs), we investigated the aqueous synthesis of zirconium MOFs. A highly versatile route was identified employing ZrOCl2 ·8H2O, H2O, acetic acid and the respective linker molecule as starting materials. These synthesis conditions are suitable to obtain zirconium MOFs with different topologies like UiO-66-(OH)2, zirconium fumarate, zirconium mesaconate, DUT-67 or MOF-808 with synthesis times of 1 to 5 h under microwave irradiation. The scalability of the synthesis of zirconium fumarate was demonstrated at multigram scale under reflux conditions using conventional dielectric heating. To ease the recovery of this MOF which bypasses filter paper as a pure product, we identified sodium polyacrylate as a suitable additive to induce aggregation of the particles. Moreover, a custom-made prototype flow reactor was developed which allows for the continuous synthesis of zirconium fumarate and UiO-66-NH2 starting from a slurry of the starting materials. The commonly employed toxic organic solvents needed for activation/purification of the MOFs could be successfully replaced by a basic aqueous solution. [ABSTRACT FROM AUTHOR]

The new aluminium based metal–organic framework [Al(OH)(O2C–C4H8–CO2)]·H2O denoted as Al-MIL-53-ADP-lp (lp stands for large pore) was synthesised under solvothermal conditions. This solid is an analogue of the archetypical aluminium terephthalate Al-MIL-53 based on the aliphatic single-chain linker molecule adipic acid (H2ADP, hexanedioic acid). In contrast to its aromatic counterparts, Al-MIL-53-ADP exhibits a structural breathing behaviour solely upon dehydration/rehydration. The crystal structure of the anhydrous compound denoted as Al-MIL-53-ADP-np (np stands for narrow pore) was determined by a combination of forcefield-based computations and Rietveld refinement of the powder X-ray diffraction data while the structure of the hydrated form Al-MIL-53-ADP-lp was derived computationally by a combination of force field based methods and Density Functional Theory calculations. Both structures were further supported by 1H, 13C and 27Al high-resolution NMR MAS 1D data coupled again with simulations. Al-MIL-53-ADP was further characterised by means of vibrational spectroscopy, elemental analysis, thermogravimetry and water vapour sorption. [ABSTRACT FROM AUTHOR]

The synthesis of Zr-MOFs under green, industrially feasible conditions was investigated. Two new compounds with bcu-topology and the fluorinated analogue of UiO-66 exhibiting fcu-topology were obtained and characterised. All products exhibit permanent porosity. In the bcu-frameworks the interaction with sulfate anions apparently induces an unusual eightfold connectivity of the Zr cluster. [ABSTRACT FROM AUTHOR]

A new sulfone-functionalized metal-organic framework [Al(OH)(SDBA)]·0.25DMF, denoted CAU-11, was synthesized using a V-shaped linker molecule 4,4'-sulfonyldibenzoic acid (H2SDBA). The crystal structure was solved from synchrotron X-ray powder diffraction data. Chains of trans corner-sharing AlO6 octahedra are interconnected by the carboxylate groups to form layers (ABAB stacking). Within the layers, hydrophobic lozenge-shaped pores with a diameter of 6.4 × 7.1 Ų are present inducing permanent porosity (aBET = 350 m² g-1 and Vmicro = 0.17 cm³ g-1). With the application of HT-methods (HT = high throughput), the isoreticular carboxylate functionalized compound [Al(OH)(H2DPSTC)]·0.5H2O (CAU-11-COOH) was synthesized using the linker molecule 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DPSDA), which hydrolyzes under the reaction conditions. Due to the additional noncoordinating carboxylic acid groups the pores are hydrophilic. Changing the molar ratio of Al3+ to linker lead to the discovery of a second new compound [Al2(OH)2(DPSTC)(H2O)2]·0.5H2O (CAU-12). In CAU-12 the linker molecule is fully deprotonated which leads to different connectivity compared to the structure of CAU-11-COOH. Thermal activation of CAU-12 leads to dehydration and transformation of the structure to [Al2(OH)2(DPSTC)]·nH2O (CAU-12-dehy). Coordinated water molecules were removed, and the coordination site is replaced by the previously noncoordinating O atom of the adjacent carboxylate group. The SO2-groups point into the pores resulting in a highly hydrophobic three-dimensional framework. The compounds exhibit high thermal stability in air at least up to 420 °C. Synthesis of CAU-11 can be easily scaled up in very high yields (98%). [ABSTRACT FROM AUTHOR]

Utilizing the aliphatic linkermolecule adipic acid IJ1,6-hexanedioic acid,HO2C-C4H8-CO2H) or 3-methyladipic acid (racemic mixture,HO2C-C4H7CH3-CO2H), the first crystalline zirconiumadipateswere synthesized under aqueous conditions. Their structures were deduced from powder X-ray diffraction data and were confirmed by Rietveld refinements. For all three compounds, the inorganic nodes are related to the well-known Zr6O4(OH)4 cluster frequently observed in aromatic zirconium MOFs. Employing ZrOCl2·8H2O and 3-methyladipic acid, a framework with bcu topology was obtained. Starting from adipic acid and Zr(SO4)2·4H2O, we observed the incorporation of sulfate into the crystal structure. Four sulfate anions are coordinated to each Zr-oxo cluster in a bidentate fashion. In this complex structure, square grids formed by Zr-oxo clusters and adipate anions and furthermore a hydrogen-bonded inorganic dia net can be observed. The third compound presented here is structurally related to the zirconium methyladipate. Using adipic acid and adding CrO4 2- under strongly acidic conditions leads to the incorporation of Cr2O72- into the bcu net. The dichromate anions are coordinated twofold to two different Zr-oxo clusters in a monodentate fashion and thus serve as inorganic connectors between the framework's nodes. [ABSTRACT FROM AUTHOR]

Employing gallium nitrate and one of the aliphatic dicarboxylic acids trans -1,4-cyclohexanedicarboxylic acid (H 2 C 8 H 10 O 4 ) or (+)-camphoric acid (H 2 C 10 H 14 O 4 ), respectively, two new metal–organic frameworks exhibiting the MIL-53-topology were synthesised in N,N-dimethylformamide. All structural characterisations were carried out based on Powder-XRD data using a combination of structural relationship, force-field calculations and Rietveld refinement. The compound based on camphoric acid [GaOH(C 10 H 14 O 4 )] or Ga-MIL-53-Cam ( 1 ) crystallises in the polar orthorhombic space group P 2 1 2 1 2 1 ( a = 14.0453(3), b = 12.0124(3), c = 6.7658(2) Å) . Ga-MIL-53-Cam exhibits an unporous dense framework which is stable up to 280 °C in air. The second compound [GaOH(C 8 H 10 O 4 )]·0.5DMF ( 2 ) or Ga-CAU-13- lp ( lp stands for large pore) crystallises in the triclinic space group P -1 ( a = 6.7114(2), b = 10.3019(3), c = 9.6265(2) Å, α = 110.743(2), β = 106.883(3), γ = 94.679(3)°). While this compound shows no porosity towards nitrogen at 77 K, water molecules can be adsorbed into the pores upon exposure to air after thermal removal of the DMF molecules. The thus obtained [GaOH(C 8 H 10 O 4 )]·H 2 O ( 3 ) or Ga-CAU-13- np ( np stand for narrow pore) exhibits the same space group symmetry as Ga-CAU-13- lp but with changed cell parameters ( P -1, a = 6.7200(2), b = 9.2179(3), c = 9.5082(3) Å, α = 107.359(2), β = 102.691(3), γ = 97.913(2)°) and thus a breathing of the framework is observed, which is shown to be reversible. Moreover, large molecules like p -xylene can be adsorbed into the pores, underlining the compound’s porosity. The particular nature of the breathing effect is substantially different compared with that known for Ga-MIL-53 based on the aromatic terephthalic acid. [ABSTRACT FROM AUTHOR]

We report the first zirconium metal-organic framework based on squaric acid, representing the member with the smallest unit cell in the isoreticular UiO-66 family. Its molecular sieving properties are strongly influenced by the monocarboxylic acid modulator incorporated during synthesis. [ABSTRACT FROM AUTHOR]

The aluminum phthalate [Al4(OH)8(BDC)2] ·H2O (where BDC2- stands for phthalate, i.e. 1,2-benzenedicarboxylate) denoted as CAU-15 (where CAU stands for Christian-Albrechts Universität) was synthesized under solvothermal conditions and thoroughly characterized. The structure was determined from X-ray powder diffraction data using a combination of direct methods and force-field calculations followed by subsequent refinement by Rietveld methods. The compound is built up by the interconnection of chains of edge-sharing AlO6 octahedra via phthalate anions, which results in a layered structure. Water molecules could be located between these layers and the dehydration behavior of the compound was studied by means of thermogravimetry and IR spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract: The use of high-throughput (HT) methods for the discovery of compounds as well as for the synthesis optimization in the field of porous aluminum MOFs is summarized. Taking the requirements of an industrial process into account, new synthesis procedures have been developed that demonstrate the versatility of the HT method. This is exemplified by the results that were obtained for the solvothermal system Al2(SO4)3·18H2O/polycarboxylic acid/H2O/DMF. Under rather mild reaction conditions, compared to the previously reported procedures, the Al-MOFs MIL-53-COOH, MIL-96, and MIL-120 were obtained employing 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, and 1,2,4,5-benzenetetracarboxylic acid, respectively. Applying the HT methodology combined with microwave(MW)-assisted heating, the synthesis procedure were rapidly established, optimized and scaled up. The obtained solids were characterized by X-ray powder diffraction (XRPD), elemental analysis, vibrational spectroscopy and nitrogen sorption measurements. The properties of these MOFs are discussed in comparison with literature values. [Copyright &y& Elsevier]

Based on the V-shaped linker molecule 4,4'-benzophenonedicarboxylic acid, the new carbonyi-functionalized metal--organic framework (MOF) [Al(OH)-(O2C-C6H4-CO-C6H4-CO2)], denoted as CAU-8, was discovered employing high-throughput methods. The compound is obtained from 4,4'-benzophenonedicarboxylic acid, A12(SO4)3·18H2O in a mixture of N,N- dimethylformamide (DMF) and water under solvothermal conditions. The structure was determined from single-crystal X-ray diffraction data (141/a, a = b= 13.0625(5), c = 52.565(2) Å). The framework is based on infinite inorganic building units of frans-connected, corner-sharing AlO6-polyhedra. Parallel Al--O-chains are arranged in layers perpendicular to [001]. Within a layer an interchain distance of ~1.1 nm is observed The orientation of the Al--O-chains within neighboring layers is perpendicular to each other, along [1OO] and [010], respectively, and an ABCDA stacking of these layers is observed. The interconnection of these orthogonally oriented chains by the V-shaped dicarboxylate ions results in the formation a three-dimensional framework structure containing one-dimensional channels with a diameter of about 8 Å. The pore walls are lined by the keto-groups. CAU-8 was thoroughly characterized by X-ray powder diffraction (XRPD), thermogravimetric measurements, IR- and Raman-spectroscopy, elemental analysis, and gas sorption experiments using N2 and H2 as adsorptives. CAU-8 is stable up to 350 °C in air and exhibits a moderate porosity with a specific surface area of SBET = 600 m²/g and a micropore volume of 0.23 cm³/g. Moreover, a detailed topological analysis of the framework was carried out, and an approach for the topological analysis of MOFs based on infinite 1-periodic building units is proposed. [ABSTRACT FROM AUTHOR]

Employing high-throughput methods, the synthesis conditionsfora series of six new MOFs based on aluminum ions and the V-shaped linkermolecule 1,3-benzene dicarboxylic acid, denoted as CAU-10-X (CAU =Christian-Albrechts-University) with the sum formula [Al(OH)(C8H3O4X)]·solvent, were established(X= functional group in 5-position of the aromaticring; X= H (1), CH3(2), OCH3(3) NO2(4), NH2(5), or OH (6)). Because of the absence of macroscopic crystals, the obtainedcompounds were structurally characterized employing XRPD-methods.The crystal structures of 1, 2, and 3were refined using Rietveld methods. Although the describedMOFs are isoreticular, they crystallize in several, sometimes noncentrosymmetricspace groups (1, 4, 6), becauseof slight structural changes induced by the functionalization. Thesespace groups were confirmed with second-harmonic generation measurements.All compounds are highly stable as confirmed by temperature-dependentXRPD and IR experiments and decompose at temperatures above 350 °C.The stabilities of all compounds in aqueous solutions of varying pHwere confirmed by XRPD measurements and their sorption propertiestoward nitrogen, hydrogen, carbon dioxide, and water vapor at lowpressures are reported. A drastic influence of the functional groupon affinity, capacity, and accessibility of the pores for these gasesis observed. These properties depend on the polarity and size of thefunctional group as well as on subtle structural differences betweenthe CAU-10-X compounds. [ABSTRACT FROM AUTHOR]

Abstract: The system Al3+/H3BTB/DMF/additive was systematically investigated using high-throughput methods and the new, microporous MOF [Al(BTB)] (BTB=1,3,5-benzenetrisbenzoate), named CAU-4 (CAU=Christian-Albrechts-University), was discovered. The synthesis was optimized changing chemical and process parameters and the final synthesis procedure was scaled up to the gram scale. CAU-4 is thermally stable up to 400°C in air and exhibits a BET-surface area of 1520m2/g and a micropore volume of 0.61cm3/g. A structure model was developed using a computationally assisted structure determination that was further validated by a good agreement with the experimental X-ray diffraction patterns and the geometrical features. The framework structure consists of isolated [AlO6]-octahedra which are bridged by carboxylate groups of the BTB-linker to form chains. These chains are connected by the tritopic aromatic building blocks, to form one-dimensional hexagonal channels with a diameter of ca. 9.6Å. [Copyright &y& Elsevier]

Cover Feature: Synthesis and Characterization of a Layered Scandium MOF Containing a Sulfone-Functionalized V-Shaped Linker Molecule (Eur. J. Inorg. The viewer is inside the pore and sees a chain of I trans i corner-sharing ScO SB 6 sb polyhedra, which are connected via V-shaped linker molecules. The viewer is inside the pore and sees a chain of I trans i corner-sharing ScO SB 6 sb polyhedra, which are connected via V-shaped linker molecules. [Extracted from the article]

An aluminium based metal-organic framework (MOF) (CAU-10-V-H, 1 , CAU stands for Christian-Albrechts-University) was designed and synthesized by employing 5-vinyl isophthalic acid (H 2 IPA-V) and 1,3-benzenedicaroxylic acid (H 2 IPA) in 1:1 molar ratio. The compound was thoroughly characterized by a number of analytical tools. The desolvated form of the material (1′) showed great sensing performance towards Pd2+ and H 2 S. Instant quenching of HEPES buffer suspension of 1′ was observed in presence of H 2 S due to formation of ground state complex by the strong interaction between H 2 S and vinyl functionality. In addition, 1′ could selectively detect Pd2+ in aqueous medium with excellent sensitivity (LOD = 110 nM). The "turn-off" behavior of the material might be attributed to the interaction between Pd2+ and vinyl functional group. In addition, the XRPD pattern remains unchanged after the sensing of both H 2 S and Pd2+. Hence, the present material is an effective dual fluorescent probe for the detection of H 2 S and Pd2+. Image 1 • A vinyl functionalized mixed-linker CAU-10 MOF was synthesized and characterized. • The material showed highly selective "turn-off" response towards H 2 S and Pd2+. • In wide pH range (2–12), the MOF material is able to detect both analytes. • The material retained its structural integrity after sensing of both analytes. • Mechanisms of both sensing events have been thoroughly investigated. [ABSTRACT FROM AUTHOR]

Two different metal‐organic frameworks containing 2,5‐pyrazinedicarboxylate (PzDC2−) as linker molecule and hexanuclear {Hf6(μ3‐O)4(μ3‐OH)4} clusters were obtained under solvothermal reaction conditions at 120 °C. Formic acid as the solvent leads to the formation of Hf‐UiO‐66‐PzDC ([Hf6(μ3‐O)4(μ3‐OH)4(OH)4(H2O)4(PzDC)4]), while the reaction in a water/formic acid mixture resulted in the crystallisation of Hf‐CAU‐22‐PzDC ([Hf6(μ3‐O)4(μ3‐OH)4(μ‐OH)2(OH)4(H2O)4(PzDC)3]). The UiO‐66 compound is a new member of the large class of UiO‐66‐type MOFs. Hf‐CAU‐22 contains a chain of condensed {Hf6O4(OH)4(μ‐OH)4} clusters as the IBU, which is new to Hf‐MOF chemistry. For both MOFs, a detailed characterization, i. e. structure refinement from powder X‐ray diffraction data, 1H‐NMR‐spectroscopy, elemental and thermogravimetric analyses and N2 sorption measurements, was carried out. Hf‐UiO‐66‐PzDC undergoes a dehydration around 215 °C and framework decomposition starts at 315 °C. From N2 sorption measurements, a maximum BET surface area of 460 m2/g was determined. The dehydration of Hf‐CAU‐22‐PzDC starts at 200 °C and the framework decomposition at 325 °C. The BET surface area was determined to 170 m2/g. [ABSTRACT FROM AUTHOR]

The improvement of the Total Isomerization Process (TIP) for the production of high‐quality gasoline with the ultimate goal of reaching a Research Octane Number (RON) higher than 92 requires the use of specific sorbents to separate pentane and hexane isomers into classes of linear, mono‐ and di‐branched isomers. Herein we report the design of a new multi‐cage microporous Fe(III)‐MOF (referred to as MIP‐214, MIP stands for materials of the Institute of Porous Materials of Paris) with a flu‐e topology, incorporating an asymmetric heterofunctional ditopic ligand, 4‐pyrazolecarboxylic acid, that exhibits an appropriate microporous structure for a thermodynamic‐controlled separation of hydrocarbon isomers. This MOF produced via a direct, scalable, and mild synthesis route was proven to encompass a unique separation of C5/C6 isomers by classes of low RON over high RON alkanes with a sorption hierarchy: (n‐hexane≫n‐pentane≈2‐methylpentane>3‐methylpentane)low RON≫(2,3‐dimethylbutane≈i‐pentane≈2,2‐dimethylbutane)high RON following the adsorption enthalpy sequence. We reveal for the first time that a single sorbent can efficiently separate such a complex mixture of high RON di‐branched hexane and mono‐branched pentane isomers from their low RON counterparts, which is a major achievement reported so far. [ABSTRACT FROM AUTHOR]

The improvement of the Total Isomerization Process (TIP) for the production of high‐quality gasoline with the ultimate goal of reaching a Research Octane Number (RON) higher than 92 requires the use of specific sorbents to separate pentane and hexane isomers into classes of linear, mono‐ and di‐branched isomers. Herein we report the design of a new multi‐cage microporous Fe(III)‐MOF (referred to as MIP‐214, MIP stands for materials of the Institute of Porous Materials of Paris) with a flu‐e topology, incorporating an asymmetric heterofunctional ditopic ligand, 4‐pyrazolecarboxylic acid, that exhibits an appropriate microporous structure for a thermodynamic‐controlled separation of hydrocarbon isomers. This MOF produced via a direct, scalable, and mild synthesis route was proven to encompass a unique separation of C5/C6 isomers by classes of low RON over high RON alkanes with a sorption hierarchy: (n‐hexane≫n‐pentane≈2‐methylpentane>3‐methylpentane)low RON≫(2,3‐dimethylbutane≈i‐pentane≈2,2‐dimethylbutane)high RON following the adsorption enthalpy sequence. We reveal for the first time that a single sorbent can efficiently separate such a complex mixture of high RON di‐branched hexane and mono‐branched pentane isomers from their low RON counterparts, which is a major achievement reported so far. [ABSTRACT FROM AUTHOR]

A microwave-assisted synthesis method for Ce(IV)-based MOFs crystallizing in the MIL-140 structure has been developed. Three different linker molecules, i.e. terephthalic acid (H2BDC), 2-chloroterephthalic acid (H2BDC-Cl) and 2,6-naphtalenedicarboxylic acid (H2NDC) that have previously been used for the synthesis of Ce-UiO-66 which contains hexanuclear Ce-O clusters as the inorganic building unit (IBU), were employed. Under solvothermal reaction conditions (140 °C) with acetonitrile as the solvent the compounds Ce-MIL-140-BDC, -BDC-Cl and -NDC, with the general composition [CeO(linker)] were obtained as microcrystalline products. For all three MOFs an extended purification process had to be carried out. The MOFs were fully characterized and the structure of Ce-MIL-140-BDC was refined against PXRD data using the Rietveld method. In contrast to Zr-MIL-140-BDC a symmetry reduction to the space group P1¯ is observed. The MIL-140 structure type is built up by infinite CeO7 polyhedra that are interconnected by dicarboxylate ions to generate 1D pores. For Ce-MIL-140-BDC the highest specific surface area of asBET = 222 m2 g−1 is observed and the MOF is thermally stable up to 370 °C. This new synthetic route to Ce(IV)-MOFs avoids the formation of the previously extremely dominant hexanuclear IBU, and paves the way for higher IBU diversity in Ce(IV)-MOFs. [ABSTRACT FROM AUTHOR]

Two new scandium‐containing coordination polymers, with the formulae {(CH3)2NH2}[Sc(BPDC)2] (1) and [Sc(OH) (BPyDC)] (2) were solvothermally synthesized by using the linear linker molecules biphenyl‐4,4'‐dicarboxylic acid (H2BPDC) and 2,2'‐bipyridine‐5,5'‐dicarboxylic acid (H2BPyDC). Crystal structures were determined from single‐crystal and powder X‐ray diffraction data, respectively. The crystal structures of 1 and 2 contain isolated ScO6 or chains of trans corner‐sharing ScO6 octahedra as the inorganic building unit (IBU), which are connected by the linker molecules to a 3D framework or a layered structure, respectively. The compounds were characterized by IR‐spectroscopy, elemental analysis, thermogravimetric analysis and photoluminescence spectroscopy. 1 shows blue emission at 400 nm, while 2 exhibits intense green emission at 550 nm with a high quantum yield (QY) of 69 %. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks containing Ga3+ ions and four differently substituted naphthalenedicarboxylates (ndc2−) have been synthesized and characterized. The Ga3+ ions are six-fold coordinated by oxygen atoms in all title compounds, but two different inorganic building units, i.e. trans corner-sharing and cis,trans edge-sharing octahedra are observed. Crystal structures were validated by Rietveld refinements against powder X-ray diffraction data. [Ga(OH)(1,4-ndc)]·2H2O crystallizes in a non-breathing MIL-53 type structure with two different pore sizes (5.5 × 5.5 Å and 9 × 9 Å). It is non-porous with respect to nitrogen but has a water adsorption capacity of about 155 mg g−1 and a thermal stability of up to 240 °C. The dense compound [Ga(OH)(1,8-ndc)] crystallizes in a new layered structure motif, which is related to the crystal structure of MIL-122 ([Al(OH)((O2C)4C6H2)]). The third and fourth compounds [Ga2(OH)4(2,3-ndc)]·H2O and [Ga(OH)(2,6-ndc)]·H2O are isoreticular to CAU-15 ([Al2(OH)4(2,3-bdc)]·H2O) and MIL-69 ([Al(OH)(2,6-ndc)]·H2O), respectively. The last two compounds are non-porous toward nitrogen but reversible dehydration was demonstrated. For comparison, the two new compounds [Al(OH)(1,8-ndc)] and [Al2(OH)4(2,3-ndc)]·H2O, which are isostructural to the newly described gallium compounds, were also synthesized and fully characterized. The Al-containing coordination polymers exhibit higher temperature stabilities compared to their isostructural Ga compounds. [ABSTRACT FROM AUTHOR]

Six different chiral and achiral alkane dicarboxylic C4-acids, i.e. succinic acid (H2SUC), dl-2-methylsuccinic acid (H2MS), 2,3-dimethylsuccinic acid (H2DMS) and aspartic acid (d-, l- and dl-H2ASP), were used to obtain Ce(iv)-MOFs via microwave assisted reactions. In water-based syntheses, MOFs with three different topologies, denoted as UiO-66 (fcu), CAU-41 (bcu) and CAU-44 (bct), were obtained within 30 min under mild reaction conditions. The MOFs were fully characterized and their structures were refined from PXRD data. The chirality of the incorporated linker molecules was confirmed by circular dichroism spectroscopy. The optical activities were also investigated by second-harmonic generation (SHG) measurements. The use of H2MS, H2DMS and H2ASP leads to the formation of a UiO-66-type structure, and a hydrated form of the common hexanuclear cluster, i.e. [Ce6(μ3-O)4(μ3-OH)4(H2O)6]12+ was observed. Rietveld refinement of the PXRD data showed an ordered arrangement of the d- and l-enantiomers in Ce-UiO-66-dl-ASP. By employing H2SUC as the linker, the other two title compounds are obtained. CAU-41, [Ce6(μ3-O)4(μ3-OH)4(SUC)4(OH)4(H2O)4], exhibits the well-known eight-fold connectivity of the hexanuclear cluster, whereas in CAU-44, [Ce6(μ3-O)4(μ3-OH)4(SUC)4(NO3)2(OH)2(H2O)2], the connection of the clusters is also achieved by nitrate ions resulting in a framework with bct topology. [ABSTRACT FROM AUTHOR]

The bifunctional linker molecule [5‐(phosphonomethyl)‐2,4‐bis(sulfonomethyl)phenyl]methanesulfonic acid (HO3S‐CH2)3‐C6H2‐CH2PO3H2 (abbreviated as H5L4) was employed in systematic high‐throughput investigations in order to discover new coordination polymers (CPs). Employing 27 metal salts of 17 different metals in this investigation, five new compounds [Mg2(HL4)(H2O)6] (1), [Pb4(L4)(OH)3] (2), [Ba2(H2L4)(OH)(H2O)] (3), [Ba2(HL4)(H2O)4] (4), and [Cd2,5(L4)(H2O)7] (5) were discovered and their crystal structures were determined. In all compounds, the sulfonate and phosphonate groups could not be resolved since the P and S atoms are statistically occupying the atom site with a ratio of 0.25 to 0.75. This is reflected in the P–O and S–O bond lengths. Four of the structures were determined from single‐crystal X‐ray diffraction data, whereas the structure of 4 was solved ab initio from powder data using real‐space methods and refined using Rietveld methods. [ABSTRACT FROM AUTHOR]

Aluminium isophthalate CAU-10 [Al(OH)(O2C–C6H4–CO2)]·nH2O and aluminium citraconate CAU-15-Cit [Al2(OH)4(O2C–C3H4–CO2)]·nH2O (where CAU stands for Christian-Albrechts-University) were investigated regarding their de- and rehydration behaviour using powder X-ray diffraction (PXRD) and volumetric gas sorption. The relative humidities (r.h.) for ad- and desorption observed by PXRD agree well with the values observed in volumetric experiments. Moreover, the kinetics of hydration and dehydration were followed by PXRD at different temperatures. For CAU-10, the hydration at ≈85% r.h. proceeds much faster than the dehydration at 0% r.h., due to the differences relative to the onset of de-/rehydration at 20% r.h. We could also observe a clear acceleration for both processes between 40 °C and 60 °C. For the layered CAU-15-Cit, the hydration proceeds much slower compared to CAU-10 while the dehydration proceeds faster. This is attributed to the higher hydrophilicity of CAU-10, as well as the associated structural changes during (de-)intercalation in CAU-15-Cit. Eventually, tentative analyses of the kinetics by Sharp–Hancock plots indicate that the sorption processes are in reasonable agreement with (pseudo-) 0th order kinetics. [ABSTRACT FROM AUTHOR]

Highlights • Metal–organic frameworks are porous materials which show many potential applications. • Germany-based researchers have provided significant contributions to this field. • Comprehensive review of unique synthesis approaches and characterization methods. • Advanced functions and the performance of these promising materials are highlighted. Abstract Metal–organic frameworks (MOFs) are constructed from a combination of inorganic and organic units to produce materials which display high porosity, among other unique and exciting properties. MOFs have shown promise in many wide ranging applications, such as catalysis and gas separations. In this review, we highlight MOF research conducted by Germany-based research groups. Specifically, we feature approaches for the synthesis of new MOFs, high-throughput MOF production, advanced characterization methods and examples of advanced functions and properties. [ABSTRACT FROM AUTHOR]

We herein investigated the synthesis of the Ce4+‐based metal‐organic framework [Ce6(μ3‐O)4(μ3‐OH)4(PZDC)4(OH)4(H2O)4] denoted as Ce‐DUT‐67‐PZDC (where DUT stands for Dresden University of Technology and PZDC2– stands for 3,5‐pyrazoledicarboxylate) by in‐situ powder X‐ray diffraction methods under solvothermal conditions using synchrotron radiation. It was observed that the obtained MOF is rapidly formed between 120 and 140 °C, but only as an intermediate product in this preparative system. After prolonged reaction times, Ce4+ is reduced to Ce3+ and reacting with formic acid from the reaction mixture to form the final product [Ce(O2CH)3]. During the formation of trivalent cerium formate, the Ce(IV)‐MOF completely re‐dissolves. Based on the composition of the reaction mixture and the recorded data, a plausible reaction mechanism was established. This mechanistic scheme includes a reversible precipitation of the Ce(IV)‐MOF under the given conditions and the reduction of Ce4+ by formate anions generated via hydrolysis of the solvent dimethylformamide. [ABSTRACT FROM AUTHOR]

A hydrazine-functionalized, highly stable Al(iii) based metal–organic framework (MOF) with CAU-10 (CAU = Christian-Albrechts-University) framework topology namely CAU-10-N2H3 (1) was specifically designed to detect lethal CN− ions in aqueous medium. The MOF was characterized by X-ray powder diffraction, infrared spectroscopy, gas sorption and thermogravimetric analyses. The isophthalate ligand in CAU-10 was functionalized by the hydrazine group to make the acidic –NH protons easily available to the CN− ions. Indeed, the activated compound (1′) showed highly selective and sensitive responses to CN− ions over other common anions with a detection limit of 0.48 μM. A rapid fluorescence enhancement was observed for 1′ with a large spectral shift (Δλ = 30 nm) in the presence of CN− ions in aqueous solution with the development of visible green fluorescence under a UV lamp. Due to the excellent detection performance to CN− by 1′ in aqueous medium, the material was further used for CN− detection in real water samples. The fluorescence increment with a large blue shift is attributed to the cyanide-induced deprotonation of the –NH group, which was confirmed by 1H NMR titration measurements. The initial photo-induced electron transfer (PET) process is prohibited by this deprotonation, which causes the fluorescence enhancement. Time-resolved fluorescence lifetime measurements suggest that 1′ can also act as a lifetime based CN− sensor. Finally, the CN− sensing ability of 1′ inside living RAW 264.7 macrophages was demonstrated through live-cell imaging investigations. [ABSTRACT FROM AUTHOR]

A precursor method has been developed to synthesize Ce(iv) MOFs that could not be prepared directly from Ce(iv) salts. Starting from Ce6 clusters, two Ce-UiO-66 analogues and four tetracarboxylate-based Ce(iv) MOFs could be synthesized. The applied method facilitates framework formation by evading reactive individual Ce(iv)-ions thereby paving the way for further development of Ce-MOFs. [ABSTRACT FROM AUTHOR]

Review: 88 refs. [ABSTRACT FROM AUTHOR]