| 1. |
- Benecke, Jannik, et al.
(författare)
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Observation of three different linker conformers in a scandium ferrocenedicarboxylate coordination polymer
- 2020
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Ingår i: CrystEngComm. - : Royal Society of Chemistry (RSC). - 1466-8033 .- 1466-8033. ; 22:34, s. 5569-5572
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Tidskriftsartikel (refereegranskat)abstract
- Electron and powder diffraction were combined to elucidate the structure of the new coordination polymer [Sc-2(FcDC)(3)] based on 1,1'-ferrocenedicarboxylate (FcDC(2-)), denoted as CAU-50. Remarkably, three different conformers of the very same linker molecule are observed, two of which serve as connectors for the scandium cations while one conformer acts as capping agent.
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| 2. |
- Benecke, Jannik, et al.
(författare)
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Polymorphous Indium Metal-Organic Frameworks Based on a Ferrocene Linker : Redox Activity, Porosity, and Structural Diversity
- 2020
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 59:14, s. 9969-9978
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Tidskriftsartikel (refereegranskat)abstract
- The metallocene-based linker molecule 1,1'-ferrocenedicarboxylic acid (H(2)FcDC) was used to synthesize four different polymorphs of composition [In(OH)(FeC12H8O4)]. Using conventional solvent-based synthesis methods and varying the synthetic parameters such as metal source, reaction temperature, and solvent, two different MOFs and one ID-coordination polymer denoted as CAU-43 (1), In-MIL-53-FcDC_a (2), and InFcDC (3) were obtained. Furthermore, thermal treatment of CAU-43 (1) at 190 degrees C under vacuum yielded a new polymorph of 2, In-MIL-53-FcDC_b (4). Both MOFs 2 and 4 crystallize in a MIL-53 type structure, but in different space groups C2/m for 2 and P (1) over bar for 4. The structures of the four title compounds were determined by single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), or a combination of three-dimensional electron diffraction measurements (3D ED) and PXRD. N-2 sorption experiments of 1, 2, and 4 showed specific surface areas of 355 m(2) g(-)(1), 110 m(2) g(-1), and 140 m(2) g(-)(1), respectively. Furthermore, the electronic properties of the title compounds were characterized via Mossbauer and EPR spectroscopy. All Mossbauer spectra showed the characteristic doublet, proving the persistence of the ferrocene moiety. In the cases of 1, 3, and 4, appreciable impurities of ferrocenium ions could be detected by electron paramagnetic resonance spectroscopy. Cyclovoltammetric experiments were performed to demonstrate the accessible redox activity of the linker molecule of the title compounds. A redox process of FcDC(2-) with oxidation (between 0.86 and 0.97 V) and reduction wave (between 0.69 and 0.80 V) was observed.
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| 3. |
- García-Palacios, Pablo, et al.
(författare)
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Evidence for large microbial-mediated losses of soil carbon under anthropogenic warming
- 2021
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Ingår i: Nature Reviews Earth and Environment. - : Springer Science and Business Media LLC. - 2662-138X. ; 2:7, s. 507-517
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Forskningsöversikt (refereegranskat)abstract
- Anthropogenic warming is expected to accelerate global soil organic carbon (SOC) losses via microbial decomposition, yet, there is still no consensus on the loss magnitude. In this Perspective, we argue that, despite the mechanistic uncertainty underlying these losses, there is confidence that a strong, positive land carbon–climate feedback can be expected. Two major lines of evidence support net global SOC losses with warming via increases in soil microbial metabolic activity: the increase in soil respiration with temperature and the accumulation of SOC in low mean annual temperature regions. Warming-induced SOC losses are likely to be of a magnitude relevant for emission negotiations and necessitate more aggressive emission reduction targets to limit climate change to 1.5 °C by 2100. We suggest that microbial community–temperature interactions, and how they are influenced by substrate availability, are promising research areas to improve the accuracy and precision of the magnitude estimates of projected SOC losses.
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| 4. |
- Rabe, Timo, et al.
(författare)
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Isoreticular Chemistry of Group 13 Metal-Organic Framework Compounds Based on V-Shaped Linker Molecules : Exceptions to the Rule?
- 2021
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 60:12, s. 8861-8869
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Tidskriftsartikel (refereegranskat)abstract
- Following the concept of isoreticular chemistry, we carried out a systematic study on Ga-containing metal–organic frameworks (MOFs) using six V-shaped linker molecules of differing sizes, geometries, and additional functional groups. The linkers included three isophthalic acid derivatives (m-H2BDC-R, R = CH3, OCH3, NHCOCH3), thiophene-2,5-dicarboxylic acid (H2TDC), and two 4,4′-sulfonyldibenzoic acid derivatives (H2SDBA, DPSTA). The crystal structures of seven compounds were elucidated by a combination of model building, single-crystal X-ray diffraction (SCXRD), three-dimensional electron diffraction (3D ED), and Rietveld refinements against powder X-ray diffraction (PXRD) data. Four new Ga-MOFs that are isoreticular with their aluminum counterparts, i.e. Ga-CAU-10-R (Ga(OH)(m-BDC-R); R = OCH3, NHCOCH3), Ga-CAU-11 (Ga(OH)(SDBA)), and Ga-CAU-11-COOH (Ga(OH)(H2DPSTC)), were obtained. For the first time large single crystals of a MOF crystallizing in the CAU-10 structure type could be isolated, i.e. Ga-CAU-10-OCH3, which permitted a detailed structural characterization. In addition, the use of 5-methylisophthalic acid and thiophene-2,5-dicarboxylic acid resulted in two new Ga-MOFs denoted Ga-CAU-49 and Ga-CAU-51, respectively, which are not isostructural with any known Al-MOF. The crystal structure of Ga-CAU-49 ([Ga4(m-HBDC-CH3)2(m-BDC-CH3)3(OH)4(H2O)]) contains an unprecedented rod-shaped inorganic building unit (IBU) of the formula ∞1{Ga16(OH)18O60}, composed of corner-sharing GaO5 and GaO6 polyhedra. In Ga-CAU-51 ([Ga(OH)(C5H2O2S)]) chains of alternating cis and trans corner-sharing GaO6 polyhedra form the IBU. A detailed characterization of the title compounds was carried out, including nitrogen gas and water vapor sorption measurements. Ga-CAU-11 was the only compound exhibiting porosity toward nitrogen with a type I isotherm, a specific surface area of aS,BET = 210 m2/g, and a micropore volume of Vmic = 0.09 cm3/g. The new MOF Ga-CAU-51 exhibits exceptional water sorption properties with a reversible S-shaped isotherm and a high uptake around p/p0 = 0.38 of mads = 370 mg/g.
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| 5. |
- Rönfeldt, Pia, et al.
(författare)
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New Scandium-containing Coordination Polymers with Linear Linker Molecules : Crystal Structures and Luminescence Properties
- 2020
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; 2020:28, s. 2737-2743
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Tidskriftsartikel (refereegranskat)abstract
- 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 Xray 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 %.
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| 6. |
- Rönfeldt, Pia, et al.
(författare)
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Water-based Synthesis and Properties of a Scandium 1,4-Naphthalenedicarboxylate
- 2020
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Ingår i: Zeitschrift für Anorganische und Allgemeines Chemie. - : Wiley. - 0044-2313 .- 1521-3749. ; 646:16, s. 1373-1379
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Tidskriftsartikel (refereegranskat)abstract
- A new scandium naphthalenedicarboxylate with the framework composition [Sc-2(1,4-NDC)(3)] (H-2-1,4-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, [Sc-2(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. [Sc-2(1,4-NDC)(3)] exhibits a high thermal stability and a ligand-based blue luminescence in the solid state at room temperature.
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| 7. |
- Wöhlbrandt, Stephan, et al.
(författare)
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A Tetratopic Phosphonic Acid for the Synthesis of Permanently Porous MOFs : Reactor Size-Dependent Product Formation and Crystal Structure Elucidation via Three-Dimensional Electron Diffraction
- 2020
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 59:18, s. 13343-13352
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Tidskriftsartikel (refereegranskat)abstract
- Following the strategy of installing porosity in coordination polymers predefined by linker geometry, we employed the new tetratopic linker molecule 1,1,2,2-tetrakis[4-phosphonophenyl]ethylene (H8TPPE) for the synthesis of new porous metal phosphonates. A high-throughput study was carried out using Ni2+ and Co2+ as metal ions, and a very strong influence of the reactor size on the product formation is observed while maintaining the same reaction parameters. Using small autoclaves (V = 250 μL), single crystals of isostructural mononuclear complexes of the composition [Ni(H3DPBP)2(H2O)4] (1) and [Co(H3DPBP)2(H2O)4] (2) are formed. They contain the linker molecule H4DPBP (4,4′-diphosphonobenzophenone), which is formed in situ by oxidation of H8TPPE. Using autoclaves with a volume of V = 2 mL, two new 3D metal–organic frameworks (MOFs) of composition [Ni2(H4TPPE)(H2O)6]·4H2O (CAU-46) and [Co2(H4TPPE)(H2O)4]·3H2O (CAU-47) were isolated in bulk quantities, and their crystal structures were determined from three-dimensional electron diffraction (3D ED) and powder X-ray diffraction data. Using even larger autoclaves (V = 30 mL), another 3D MOF of the composition [Co2(H4TPPE)]·6H2O (Co-CAU-48) was obtained, and a structure model was established via 3D ED measurements. Remarkably, the isostructural compound [Ni2(H4TPPE)]·9H2O (Ni-CAU-48) is only obtained indirectly, i.e., via thermal activation of CAU-46. As the chosen linker geometry leads to the formation of MOFs, topological analyses were carried out, highlighting the different connectivities observed in the three frameworks. Porosity of the compounds was proven via water sorption experiments, resulting in uptakes of 126 mg/g (CAU-46), 105 mg/g (CAU-47), 210 mg/g (Ni-CAU-48), and 109 mg/g (Co-CAU-48).
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