5 research outputs found

    Doubling the Carbonate-Binding Capacity of Nanojars by the Formation of Expanded Nanojars

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    Anion binding and extraction from solutions is currently a dynamic research topic in the field of supramolecular chemistry. A particularly challenging task is the extraction of anions with large hydration energies, such as the carbonate ion. Carbonate-binding complexes are also receiving increased interest due to their relevance to atmospheric CO2 fixation. Nanojars are a class of self-assembled, supramolecular coordination complexes that have been shown to bind highly hydrophilic anions and to extract even the most hydrophilic ones, including carbonate, from water into aliphatic solvents. Here we present an expanded nanojar that is able to bind two carbonate ions, thus doubling the previously reported carbonate-binding capacity of nanojars. The new nanojar is characterized by detailed single-crystal X-ray crystallographic studies in the solid state and electrospray ionization mass spectrometric (including tandem MS/MS) studies in solution

    An octanuclear nickel(II) pyrazolate cluster with a cubic Ni8 core and its methyl- and n-octyl-functionalized derivatives

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    The molecular and crystal structure of a discrete [Ni8(μ4-OH)6(μ-4-Rpz)12]2− (R = H; pz = pyrazolate anion, C3H3N2−) cluster with an unprecedented, perfectly cubic arrangement of its eight Ni centers is reported, along with its lower-symmetry alkyl-functionalized (R = methyl and n-octyl) derivatives. Crystals of the latter two were obtained with two identical counter-ions (Bu4N+), whereas the crystal of the complex with the parent pyrazole ligand has one Me4N+ and one Bu4N+ counter-ion. The methyl derivative incorporates 1,2-dichloroethane solvent molecules in its crystal structure, whereas the other two are solvent-free. The compounds are tetrabutylazanium tetramethylazanium hexa-μ4-hydroxido-dodeca-μ2-pyrazolato-hexahedro-octanickel, (C16H36N)(C4H12N)[Ni8(C3H3N2)12(OH)6] or (Bu4N)(Me4N)[Ni8(μ4-OH)6(μ-pz)12] (1), bis(tetrabutylazanium) hexa-μ4-hydroxido-dodeca-μ2-(4-methylpyrazolato)-hexahedro-octanickel 1,2-dichloroethane 7.196-solvate, (C16H36N)2[Ni8(C4H5N2)12(OH)6]·7.196C2H4Cl2 or (Bu4N)2[Ni8(μ4-OH)6(μ-4-Mepz)12]·7.196(ClCH2CH2Cl) (2), and bis(tetrabutylazanium) hexa-μ4-hydroxido-dodeca-μ2-(4-octylpyrazolato)-hexahedro-octanickel, (C16H36N)2[Ni8(C11H19N2)12(OH)6] or (Bu4N)2[Ni8(μ4-OH)6(μ-4-nOctpz)12] (3). All counter-ions are disordered (with the exception of one Bu4N+ in 3). Some of the octyl chains of 3 (the crystal is twinned by non-merohedry) are also disordered. Various structural features are discussed and contrasted with those of other known [Ni8(μ4-OH)6(μ-4-Rpz)12]2− complexes, including extended three-dimensional metal–organic frameworks. In all three structures, the Ni8 units are lined up in columns

    Isomorphous but No Dead Ringer: Contrasting the Supramolecular Binding of Tetrafluoroberyllate and Sulfate Ions by Nanojars

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    An extensive single-crystal X-ray crystallographic study of 11 nanojar structures (of which seven are novel) of the formula [anion⊂{cis-CuII(μ-OH)(μ-pz)}n]2– (anion = BeF42–, n = 28, 31, 32, CunBeF4; anion = SO42–, n = 28, 31, CunSO4; pz = pyrazolate, C3H3N2–) has been carried out, providing a detailed description of isomorphism and pseudopolymorphism in nanojars. The results point to a remarkable variety in the shape of the constituent [cis-CuII(μ-OH)(μ-pz)]x (Cux; x = 6, 8, 9, 10, 12 and 14) metallamacrocycles, despite only small differences in the coordination environment of the individual Cu2+ centers. The flexibility of the Cux rings and, ultimately, of the nanojar framework allows for the incarceration of different anions with slightly different dimensions in a nanojar of a given size, resulting in the formation of isomorphous structures in the case of CunBeF4 and CunSO4. Selectivity studies monitored by electrospray-ionization mass spectrometry (ESI-MS) and proton nuclear magnetic resonance spectroscopy (1H NMR) reveal that despite the virtually identical H-bonding pattern around the two anions in nanojars of a given size, SO42– is strongly preferred over BeF42–. The origins of this selectivity are discussed, along with the nature of bonding in the two isosteric anions. Lastly, the crystal structure of (Bu4N)3Be2F7(H2O)3 documents the formation of the Be2F73– ion from BeF42–

    SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

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    Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population
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