This file was created by the TYPO3 extension publications --- Timezone: CEST Creation date: 2026-05-19 Creation time: 15:35:48 --- Number of references 8 Liquid ammonia as the original solvent for Zintl anions has been replaced by easier to handle or more versatile solvents in most recent Zintl chemistry. However, methodological advances have made it possible to structurally investigate the anions in ammoniate crystals via crystallography or in the solutions themselves via nuclear magnetic resonance. While in some cases liquid ammonia acts as an innocent solvent, it also provides different possibilities of direct involvement in chemical reactions. In addition to simple dissolution without changes to the anions observed in the solid starting materials, protonation of the anion, incongruent dissolution involving redox processes, and further oxidation and reduction products have been observed. The use of the solvent liquid ammonia under ambient pressure is limited to low temperatures, which in turn allows the monitoring of kinetically stabilized species, some of which cannot be accessed at higher temperatures. In this work, the available literature reports are summarized or referenced, and compounds that have been characterized as new ammoniate crystals are presented and contextualized. Innocent dissolution is observed for clusters involved in K2.9Rb5.1[Si4][Si9]·15NH3, Cs4Sn9·12NH3, Cs4Pb9·5NH3, and [Rb@[18]crown-6]2[Rb@[2.2.2]crypt]Rb[Ge9]·4NH3. Formal protonation of [Ge4]4– results in the crystallization of [Na@[2.2.2]crypt]2[H2Ge4]·3NH3. Tt52– (Tt = Sn or Pb) and HSi93– cannot be accessed in a binary solid state material but can be crystallized in co-crystals of PPh3 in [Rb@[2.2.2]crypt]2[Sn5][PPh3]2·NH3, [Rb@[2.2.2]crypt]2[Pb5][PPh3]2·NH3, and [K@[2.2.2]crypt]3[HSi9][PPh3]·5NH3. article 2024 8 09 1520-510X,0020-1669 10.1021/acs.inorgchem.4c01817 Inorganic Chemistry 63 American Chemical Society (ACS) 20240-20249 43 https://epub.uni-regensburg.de/id/eprint/58875 Stefanie Gärtner Michael Witzmann Corinna Lorenz-Fuchs Ruth M. Gschwind Nikolaus Korber A simultaneously protonated and functionalized silicide cluster [(NHCCu)-Cu-Dipp(eta(4)-Si-9)H](2-) was detected and characterized in liquid ammonia by NMR spectroscopy. Key NMR results were corroborated by theoretical calculations. H-1-NMR line-widths at variable temperatures revealed that proton hopping in the metalated complex [(NHCCu)-Cu-Dipp(eta(4)-Si-9)H](2-) is less pronounced than in the non-complexed silicide [HSi9](3-). Besides [HSi9](3-) and [(NHCCu)-Cu-Dipp(eta(4)-Si-9)H](2-) also the unprotonated analogous cluster [(NHCCu)-Cu-Dipp(eta(4)-Si-9)](3-) was detected in solution. In addition, a new Si-29-NMR signal was obtained in the course of Si-29-NMR studies that we assigned to [(NHCCu)-Cu-Dipp(eta(4)-Si-9)](3-). The isolation of crystals of (K[2.2.2]-crypt)(2)K0.48Rb3.52[(NHCCu)-Cu-Dipp(eta(4)-Si-9)](2) prove the availability of the non-protonated (NHCCu)-Cu-Dipp(eta(4)-Si-9) fragment in solution. To the best of our knowledge the detection of [(NHCCu)-Cu-Dipp(eta(4)-Si-9)H](2-) represents the first case of a protonated and coinage metalated group 14 Zintl cluster in solution so far. article 2021 6 29 1434-1948,1099-0682 10.1002/ejic.202100419 European Journal of Inorganic Chemistry 36 Wiley

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3684-3690 https://epub.uni-regensburg.de/id/eprint/46294 Verena Streitferdt Susanne M. Tiefenthaler Ilya G. Shenderovich Stefanie Gärtner Nikolaus Korber Ruth M. Gschwind Crystals of the two new compounds ((NHCAu)-Au-tBu)(3)NHCl and [((NHCAu)-Au-tBu)(6)(eta(2)-Si-4)]Cl-2 center dot 7NH(3)could be isolated from the reaction of Rb(6)Cs(6)Si(17)with (NHCAuCl)-Au-tBu in the presence of [2.2.2]-cryptand in liquid ammonia. Both compounds were characterized by single-crystal X-ray diffraction and crystallize trigonally without any alkali metals or chelating ligands. Additionally, the crystal of [((NHCAu)-Au-tBu)(6)(eta(2)-Si-4)]Cl-2 center dot 7NH(3)was further interpreted by means of ELF and NBO calculations. In the case of ((NHCAu)-Au-tBu)(3)NHCl, NMR experiments provided an exceptional insight into the reaction processes in solution and allowed for the detection of sequential precursors. In the class of capped gold triangles ((NHCAu)-Au-tBu)(3)NHCl impresses with its unique characteristics of being capped by an imide and bound toN-heterocyclic carbenes as ligands instead of the ubiquitously employed phosphines. The gold capped silicon tetrahedron [((NHCAu)-Au-tBu)(6)(eta(2)-Si-4)]Cl-2 center dot 7NH(3)represents the first known silicide-gold compound, as well as the first known functionalized Zintl anion, crystallized with a cationic central moiety. article 2020 9 0044-2313,1521-3749 10.1002/zaac.202000275 Zeitschrift für Anorganische und Allgemeine Chemie (ZAAC) 646 Wiley

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1595-1602 18 https://epub.uni-regensburg.de/id/eprint/44609 Susanne Tiefenthaler Verena Streitferdt Josef Baumann Stefanie Gärtner Ruth Maria Gschwind Nikolaus Korber The existence of [mu-HSi4](3-) in liquid ammonia solutions is confirmed by H-1 and Si-29 NMR experiments. Both NMR and quantum chemical calculations reveal that the H atom bridges two Si atoms of the [Si-4](4-) cluster, contrary to the expectation that it is located at one vertex Si of the tetrahedron. The calculations also indicate that in the formation of [mu-HSi4](3-), protonation is driven by a high charge density and an increase of electron delocalization compared to [Si-4](4-). Additionally, [Si-5](2-) was detected for the first time and characterized by NMR. Calculations show that it is resistant to protonation, owing to a strong charge delocalization, which is significantly reduced upon protonation. Thus, our methods reveal three silicides in liquid ammonia: unprotonated [Si-5](2-), terminally protonated [HSi9](3-), and bridge-protonated [mu-HSi4](3-). The protonation trend can be roughly predicted by the difference in charge delocalization between the parent compound and the product, which can be finely tuned by the presence of counter ions in solution. article 2019 1433-7851,1521-3773 10.1002/anie.201812955 Angewandte Chemie International Edition Wiley

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3133-3137 58 https://epub.uni-regensburg.de/id/eprint/38198 Florian Hastreiter Corinna Lorenz Johnny Hioe Stefanie Gärtner Lokesh Nanjundappa Nikolaus Korber Ruth M. Gschwind We report on the first unambiguous detection of the elusive [HSi9](3-) anion in solutions of liquid ammonia by various Si-29 and H-1 NMR experiments including chemical exchange saturation transfer (CEST). The characteristic multiplicity patterns of both the Si-29 and H-1 resonances together with CEST and a partially reduced H-1,Si-29 coupling constant indicate the presence of a highly dynamic Si-8 entity and a Si-H moiety with slow proton hopping. Theoretical calculations corroborate both reorganization of Si-8 on the picosecond timescale via low vibrational modes and proton hopping. In addition, in a single-crystal X-ray study of (K(DB[18]crown-6))(K([2.2.2]crypt))(2)[HSi9]center dot 8.5 NH3, the Hatom was unequivocally localized at one vertex of the basal square of the monocapped square-antiprismatic cluster. Thus experimental studies and theoretical considerations provide unprecedented insight into both the structure and the dynamic behavior of these cluster anions, which hitherto had been considered to be rigid. article 2018 1433-7851,1521-3773 10.1002/anie.201807080 Angewandte Chemie International Edition 57 Wiley

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12956-12960 https://epub.uni-regensburg.de/id/eprint/37669 Corinna Lorenz Florian Hastreiter Johnny Hioe Lokesh Nanjundappa Stefanie Gärtner Nikolaus Korber R. M. Gschwind Homoatomic polyanions of post-transition main-group metals, namely, Zintl anions, are precast in analogous Zintl phases and can react in solution to form new materials. Despite comprehensible reaction approaches, the formed products cannot be planned in advance, as hitherto undetected and therefore disregarded side reactions take place. The outcomes and interpretations of the reactions of Zintl anions are so far based mainly on crystal structures, which only allow characterization of the product that has the lowest solubility. Here we present the results of our investigation of the stability of highly charged tin Zintl anions in liquid ammonia, which is not exclusively based on solution effects but also on the oxidative influence of the solvent. This allows for a deeper understanding of the ongoing processes in solution and opens doors to the directed synthesis of transition metal complexes of Sn-4(4-), here shown by its reactivity towards MesCu. article 2015 0947-6539,1521-3765 10.1002/chem.201501100 Chem. Eur. J. 21 WILEY-V C H VERLAG GMBH

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14539-14544 41 https://epub.uni-regensburg.de/id/eprint/32378 Franziska Fendt Carina Koch Maria Neumeier Stefanie Gärtner Ruth Maria Gschwind Nikolaus Korber Two new trigonal and tetragonal polymorphs of the title compound, iodidotris(tetrahydrofuran-kappaO)lithium, are presented, which both include the isolated ion pair Li(THF)3+.I-. One Li-I ion contact and three tetrahydrofuran (THF) molecules complete the tetrahedral coordination of the lithium cation. The three-dimensional arrangement in the two polymorphs differs notably. In the trigonal structure, the ion pair is located on a threefold rotation axis of space group P-3 and only one THF molecule is present in the asymmetric unit. In the crystal, strands of ion pairs parallel to 001 are observed with an eclipsed conformation of the THF molecules relative to the Li...I axis of two adjacent ion pairs. In contrast, the tetragonal polymorph shows a much larger unit cell in which all atoms are located on general positions of the space group I41cd. The resulting three-dimensional arrangement shows helical chains of ion pairs parallel to 001. Apart from van der Waals contacts, no remarkable intermolecular forces are present between the isolated ion pairs in both structures. article 2014 10.1107/S160053681402529X Acta Crystallographica Section E 70 Blackwell Publishing 555-558 12 https://epub.uni-regensburg.de/id/eprint/30998 Stefanie Gärtner Tobias Gärtner Ruth Maria Gschwind Nikolaus Korber article 2013 10.1002/anie.201209578 Angewandte Chemie International Edition 52 WILEY-V C H VERLAG GMBH

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4483-4486 https://epub.uni-regensburg.de/id/eprint/27988 Maria Neumeier Franziska Fendt Stefanie Gärtner Carina Koch Tobias Gärtner Nikolaus Korber Ruth M. Gschwind