TY - JOUR A1 - Philipp, Michael S. M. A1 - Bertermann, Rüdiger A1 - Radius, Udo T1 - Activation of Ge−H and Sn−H Bonds with N‐Heterocyclic Carbenes and a Cyclic (Alkyl)(amino)carbene JF - Chemistry – A European Journal N2 - A study of the reactivity of several N‐heterocyclic carbenes (NHCs) and the cyclic (alkyl)(amino)carbene 1‐(2,6‐di‐iso‐propylphenyl)‐3,3,5,5‐tetramethyl‐pyrrolidin‐2‐ylidene (cAAC\(^{Me}\)) with the group 14 hydrides GeH2Mes2 and SnH2Me2 (Me=CH\(_{3}\), Mes=1,3,5‐(CH\(_{3}\))\(_{3}\)C\(_{6}\)H\(_{2}\)) is presented. The reaction of GeH\(_{2}\)Mes\(_{2}\) with cAAC\(^{Me}\) led to the insertion of cAAC\(^{Me}\) into one Ge−H bond to give cAAC\(^{Me}\)H−GeHMes\(_{2}\) (1). If 1,3,4,5‐tetramethyl‐imidazolin‐2‐ylidene (Me\(_{2}\)Im\(^{Me}\)) was used as the carbene, NHC‐mediated dehydrogenative coupling occurred, which led to the NHC‐stabilized germylene Me\(_{2}\)Im\(^{Me}\)⋅GeMes\(_{2}\) (2). The reaction of SnH\(_{2}\)Me\(_{2}\) with cAAC\(^{Me}\) also afforded the insertion product cAAC\(^{Me}\)H−SnHMe\(_{2}\) (3), and reaction of two equivalents Me\(_{2}\)Im\(^{Me}\) with SnH\(_{2}\)Me\(_{2}\) gave the NHC‐stabilized stannylene Me\(_{2}\)Im\(^{Me}\)⋅SnMe\(_{2}\) (4). If the sterically more demanding NHCs Me\(_{2}\)Im\(^{Me}\), 1,3‐di‐isopropyl‐4,5‐dimethyl‐imidazolin‐2‐ylidene (iPr\(_{2}\)Im\(^{Me}\)) and 1,3‐bis‐(2,6‐di‐isopropylphenyl)‐imidazolin‐2‐ylidene (Dipp\(_{2}\)Im) were employed, selective formation of cyclic oligomers (SnMe\(_{2}\))\(_{n}\) (5; n=5–8) in high yield was observed. These cyclic oligomers were also obtained from the controlled decomposition of cAAC\(^{Me}\)H−SnHMe\(_{2}\) (3). KW - cyclic alkyl(amino)carbenes KW - germanium KW - hydrides KW - N-heterocyclic carbenes KW - tin Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-311929 VL - 29 IS - 3 ER - TY - JOUR A1 - Cataldi, Eleonora A1 - Raschig, Martina A1 - Gutmann, Marcus A1 - Geppert, Patrick T. A1 - Ruopp, Matthias A1 - Schock, Marvin A1 - Gerwe, Hubert A1 - Bertermann, Rüdiger A1 - Meinel, Lorenz A1 - Finze, Maik A1 - Nowak‐Król, Agnieszka A1 - Decker, Michael A1 - Lühmann, Tessa T1 - Amber Light Control of Peptide Secondary Structure by a Perfluoroaromatic Azobenzene Photoswitch JF - ChemBioChem N2 - The incorporation of photoswitches into the molecular structure of peptides and proteins enables their dynamic photocontrol in complex biological systems. Here, a perfluorinated azobenzene derivative triggered by amber light was site‐specifically conjugated to cysteines in a helical peptide by perfluoroarylation chemistry. In response to the photoisomerization (trans→cis) of the conjugated azobenzene with amber light, the secondary structure of the peptide was modulated from a disorganized into an amphiphilic helical structure. KW - amber light KW - decafluoroazobezene KW - peptide stapling KW - photocontrol KW - perfluoroarylation Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312480 VL - 24 IS - 5 ER - TY - JOUR A1 - Philipp, Michael S. M. A1 - Bertermann, Rüdiger A1 - Radius, Udo T1 - N‐Heterocyclic Carbene and Cyclic (Alkyl)(amino)carbene Adducts of Germanium(IV) and Tin(IV) Chlorides and Organyl Chlorides JF - European Journal of Inorganic Chemistry N2 - A study on the reactivity of N‐heterocyclic carbenes (NHCs) and the cyclic (alkyl)(amino)carbene cAAC\(^{Me}\) with selected germanium(IV) and tin(IV) chlorides and organyl chlorides is presented. The reactions of the NHCs Me\(_{2}\)Im\(^{Me}\), iPr\(_{2}\)Im\(^{Me}\) and Dipp2Im with the methyl chlorides ECl\(_{2}\)Me\(_{2}\) afforded the adducts NHC ⋅ ECl\(_{2}\)Me\(_{2}\) (E=Ge (1), Sn (2)), NHC=Me\(_{2}\)Im\(^{Me}\) (a), iPr\(_{2}\)Im\(^{Me}\) (b), Dipp\(_{2}\)Im (c)). The reaction of Me2Im\(^{Me}\) with GeCl\(_{4}\) led to isolation of Me\(_{2}\)Im\(^{Me}\) ⋅ GeCl\(_{4}\) (3), the reaction of iPr\(_{2}\)Im\(^{Me}\) with SnCl\(_{4}\) in THF afforded the THF adduct iPr\(_{2}\)Im\(^{Me}\) ⋅ SnCl\(_{4}\) ⋅ THF (4). Dipp\(_{2}\)Im ⋅ GeCl\(_{2}\)Me\(_{2}\) (1 c) isomerized into the backbone coordinated imidazolium salt [aDipp\(_{2}\)Im ⋅ GeClMe\(_{2}\)][Cl] (5) upon thermal treatment. The reactions of cAAC\(^{Me}\) with (i) ECl\(_{2}\)R\(_{2}\) (E=Ge, Sn) gave the adducts cAAC\(^{Me}\) ⋅ ECl\(_{2}\)R\(_{2}\) (R=Me: E=Ge (6); Sn (7); Ph: E=Ge (8)), with (ii) GeClMe\(_{3}\) and GeCl\(_{4}\) the salts [cAAC\(^{Me}\) ⋅ GeMe\(_{3}\)][Cl] (9) and [cAACMeCl][GeCl\(_{3}\)] (10), and (iii) with SnCl\(_{4}\) the salt [cAACMeCl][SnCl\(_{3}\)] (11) and the adduct cAAC\(^{Me}\) ⋅ SnCl\(_{4}\) (12). Reduction of 2 a with KC\(_{8}\) afforded the NHC‐stabilized stannylene Me\(_{2}\)Im\(^{Me}\) ⋅ SnMe\(_{2}\) 13, reduction of 7 with either KC8 or 1,4‐bis‐(trimethylsilyl)‐1,4‐dihydropyrazin in the presence of SnCl\(_{2}\)Me\(_{2}\) yielded cAAC\(^{Me}\) ⋅ SnMe\(_{2}\) ⋅ SnMe\(_{2}\)Cl\(_{2}\) (14). Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293865 VL - 2022 IS - 32 ER - TY - JOUR A1 - Häring, Mathias A1 - Kerpen, Christoph A1 - Ribbeck, Tatjana A1 - Hennig, Philipp T. A1 - Bertermann, Rüdiger A1 - Ignat’ev, Nikolai V. A1 - Finze, Maik T1 - Dismutation of Tricyanoboryllead Compounds: The Homoleptic Tetrakis(tricyanoboryl)plumbate Tetraanion JF - Angewandte Chemie N2 - A series of unprecedently air-stable (tricyanoboryl)plumbate anions was obtained by the reaction of the boron-centered nucleophile B(CN)\(_{3}\)\(^{2-}\) with triorganyllead halides. Salts of the anions [R\(_{3}\)PbB(CN)\(_{3}\)]\(^{-}\) (R=Ph, Et) were isolated and found to be stable in air at room temperature. In the case of Me\(_{3}\)PbHal (Hal=Cl, Br), a mixture of the anions [Me\(_{4-n}\)Pb{B(CN)\(_{3}\)}\(_{n}\)]\(^{n-}\) (n=1, 2) was obtained. The [Et\(_{3}\)PbB(CN)\(_{3}\)]− ion undergoes stepwise dismutation in aqueous solution to yield the plumbate anions [Et4\(_{4-n}\)Pb{B(CN)\(_{3}\)}\(_{n}\)]\(^{n-}\) (n=1–4) and PbEt\(_{4}\) as by-product. The reaction rate increases with decreasing pH value of the aqueous solution or by bubbling O\(_{2}\) through the reaction mixture. Adjustment of the conditions allowed the selective formation and isolation of salts of all anions of the series [Et\(_{4-n}\)Pb{B(CN)\(_{3}\)}\(_{n}\)]\(^{n-}\) (n=2–4) including the homoleptic tetraanion [Pb{B(CN)\(_{3}\)}\(_{4}\)]\(^{4-}\). KW - anions KW - boron KW - cyanoborates KW - dismutations KW - lead Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318257 VL - 61 IS - 24 ER - TY - JOUR A1 - Zapf, Ludwig A1 - Peters, Sven A1 - Bertermann, Rüdiger A1 - Radius, Udo A1 - Finze, Maik T1 - Tricyanoborane‐Functionalized Anionic N‐Heterocyclic Carbenes: Adjustment of Charge and Stereo‐Electronic Properties JF - Chemistry – A European Journal N2 - The 1‐methyl‐3‐(tricyanoborane)imidazolin‐2‐ylidenate anion (2) was obtained in high yield by deprotonation of the B(CN)3‐methylimidazole adduct 1. Regarding charge and stereo‐electronic properties, anion 2 closes the gap between well‐known neutral NHCs and the ditopic dianionic NHC, the 1,3‐bis(tricyanoborane)imidazolin‐2‐ylidenate dianion (IIb). The influence of the number of N‐bonded tricyanoborane moieties on the σ‐donating and π‐accepting properties of NHCs was assessed by quantum chemical calculations and verified by experimental data on 2, IIb, and 1,3‐dimethylimidazolin‐2‐ylidene (IMe, IIa). Therefore NHC 2, which acts as a ditopic ligand via the carbene center and the cyano groups, was reacted with alkyl iodides, selenium, and [Ni(CO)\(_{4}\)] yielding alkylated imidazoles 3 and 4, the anionic selenium adduct 5, and the anionic nickel tricarbonyl complex 8, respectively. The results of this study prove that charge, number of coordination sites, buried volume (%V\(_{bur}\)) and σ‐donor and π‐acceptor abilities of NHCs can be effectively fine‐tuned via the number of tricyanoborane substituents. KW - N-heterocyclic carbene KW - anionic carbene KW - boron KW - cyanoborate KW - imidazolate Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-287200 VL - 28 IS - 39 ER - TY - JOUR A1 - He, Jiang A1 - Rauch, Florian A1 - Friedrich, Alexandra A1 - Krebs, Johannes A1 - Krummenacher, Ivo A1 - Bertermann, Rüdiger A1 - Nitsch, Jörn A1 - Braunschweig, Holger A1 - Finze, Maik A1 - Marder, Todd B. T1 - Phenylpyridyl-fused boroles: a unique coordination mode and weak B-N coordination-induced dual fluorescence JF - Angewandte Chemie International Edition N2 - Phenylpyridyl-fused boroles [TipPBB1]\(_4\) and TipPBB2 were synthesized and their properties investigated. [TipPBB1]\(_4\) forms a tetramer in both the solid state and solution. TipPBB2 contains a 4-coordinate boron atom in the solid state but dissociates to give a 3-coordinate boron species in solution. TipPBB2 shows interesting temperature-dependent dual fluorescence in solution because of the equilibrium between 3- and 4-coordinate boron species due to weak N⋅⋅⋅B intermolecular coordination. KW - inorganic chemistry KW - weak intermolecular coordination KW - boroles KW - dual fluorescence KW - equilibrium KW - tetramers Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256423 VL - 60 IS - 9 ER - TY - JOUR A1 - Schneider, Leon N. A1 - Tanzer Krauel, Eva-Maria A1 - Deutsch, Carl A1 - Urbahns, Klaus A1 - Bischof, Tobias A1 - Maibom, Kristina A. M. A1 - Landmann, Johannes A1 - Keppner, Fabian A1 - Kerpen, Christoph A1 - Hailmann, Michael A1 - Zapf, Ludwig A1 - Knuplez, Tanja A1 - Bertermann, Rüdiger A1 - Ignat'ev, Nikolai V. A1 - Finze, Maik T1 - Stable and Storable N(CF\(_{3}\))\(_{2}\) Transfer Reagents JF - Chemistry—A European Journal N2 - Fluorinated groups are essential for drug design, agrochemicals, and materials science. The bis(trifluoromethyl)amino group is an example of a stable group that has a high potential. While the number of molecules containing perfluoroalkyl, perfluoroalkoxy, and other fluorinated groups is steadily increasing, examples with the N(CF\(_{3}\))\(_{2}\) group are rare. One reason is that transfer reagents are scarce and metal-based storable reagents are unknown. Herein, a set of Cu\(^{I}\) and Ag\(^{I}\) bis(trifluoromethyl)amido complexes stabilized by N- and P-donor ligands with unprecedented stability are presented. The complexes are stable solids that can even be manipulated in air for a short time. They are bis(trifluoromethyl)amination reagents as shown by nucleophilic substitution and Sandmeyer reactions. In addition to a series of benzylbis(trifluoromethyl)amines, 2-bis(trifluoromethyl)amino acetate was obtained, which, upon hydrolysis, gives the fluorinated amino acid N,N-bis(trifluoromethyl)glycine. KW - silver KW - amination KW - copper KW - fluorinated ligands KW - N ligands Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256890 VL - 27 IS - 42 ER - TY - JOUR A1 - Saalfrank, Christian A1 - Fantuzzi, Felipe A1 - Kupfer, Thomas A1 - Ritschel, Benedikt A1 - Hammond, Kai A1 - Krummenacher, Ivo A1 - Bertermann, Rüdiger A1 - Wirthensohn, Raphael A1 - Finze, Maik A1 - Schmid, Paul A1 - Engel, Volker A1 - Engels, Bernd A1 - Braunschweig, Holger T1 - cAAC‐Stabilized 9,10‐diboraanthracenes—Acenes with Open‐Shell Singlet Biradical Ground States JF - Angewandte Chemie International Edition N2 - Narrow HOMO–LUMO gaps and high charge‐carrier mobilities make larger acenes potentially high‐efficient materials for organic electronic applications. The performance of such molecules was shown to significantly increase with increasing number of fused benzene rings. Bulk quantities, however, can only be obtained reliably for acenes up to heptacene. Theoretically, (oligo)acenes and (poly)acenes are predicted to have open‐shell singlet biradical and polyradical ground states, respectively, for which experimental evidence is still scarce. We have now been able to dramatically lower the HOMO–LUMO gap of acenes without the necessity of unfavorable elongation of their conjugated π system, by incorporating two boron atoms into the anthracene skeleton. Stabilizing the boron centers with cyclic (alkyl)(amino)carbenes gives neutral 9,10‐diboraanthracenes, which are shown to feature disjointed, open‐shell singlet biradical ground states. KW - acenes KW - biradicals KW - bond Activation KW - boron KW - heterocycles Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-217795 VL - 59 IS - 43 SP - 19338 EP - 19343 ER - TY - JOUR A1 - Brunecker, Carina A1 - Müssig, Jonas H. A1 - Arrowsmith, Merle A1 - Fantuzzi, Felipe A1 - Stoy, Andreas A1 - Böhnke, Julian A1 - Hofmann, Alexander A1 - Bertermann, Rüdiger A1 - Engels, Bernd A1 - Braunschweig, Holger T1 - Boranediyl‐ and Diborane(4)‐1,2‐diyl‐Bridged Platinum A‐Frame Complexes JF - Chemistry – A European Journal N2 - Diplatinum A‐frame complexes with a bridging (di)boron unit in the apex position were synthesized in a single step by the double oxidative addition of dihalo(di)borane precursors at a bis(diphosphine)‐bridged Pt\(^{0}\)\(_{2}\) complex. While structurally analogous to well‐known μ‐borylene complexes, in which delocalized dative three‐center‐two‐electron M‐B‐M bonding prevails, theoretical investigations into the nature of Pt−B bonding in these A‐frame complexes show them to be rare dimetalla(di)boranes displaying two electron‐sharing Pt−B σ‐bonds. This is experimentally reflected in the low kinetic stability of these compounds, which are prone to loss of the (di)boron bridgehead unit. KW - boron KW - bonding KW - EDA-NOCV KW - oxidative addition KW - platinum Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-214707 VL - 26 IS - 39 SP - 8518 EP - 8523 ER - TY - JOUR A1 - Muessig, Jonas H. A1 - Lisinetskaya, Polina A1 - Dewhurst, Rian D. A1 - Bertermann, Rüdiger A1 - Thaler, Melanie A1 - Mitric, Roland A1 - Braunschweig, Holger T1 - Dibortetraiodid (B\(_2\)I\(_4\)) ist im Festkörper ein Polymer aus sp3‐hybridisiertem Bor JF - Angewandte Chemie N2 - Anhand der ersten Festkörperstrukturen von Dibortetraiodid (B\(_2\)I\(_4\)) wird gezeigt, dass dieses nicht, wie lange angenommen, analog zu den leichteren Dibortetrahalogeniden B\(_2\)F\(_4\), B\(_2\)Cl\(_4\) und B\(_2\)Br\(_4\) in allen Aggregatzuständen in Form diskreter Moleküle mit planaren, dreifach koordinierten Boratomen vorliegt. Röntgenstrukturanalysen, Festkörper‐NMR‐ und IR‐Messungen zeigen, dass B\(_2\)I\(_4\) im Festkörper in zwei polymeren Konformeren vorkommt, die tetraedrisch koordinierte Boratome enthalten. Anhand von DFT‐Rechnungen werden die IR‐Spektren in Lösung und im Festkörper simuliert und mit den experimentellen Daten verglichen. KW - Bor KW - Diboran KW - DFT-Rechnungen KW - Festkörperstrukturen KW - Halogene Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-219653 VL - 132 IS - 14 ER -