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 - Brückner, Tobias A1 - Fantuzzi, Felipe A1 - Stennett, Tom E. A1 - Krummenacher, Ivo A1 - Dewhurst, Rian D. A1 - Engels, Bernd A1 - Braunschweig, Holger T1 - Isolation of neutral, mono-, and dicationic B\(_2\)P\(_2\) rings by diphosphorus addition to a boron-boron triple bond JF - Angewandte Chemie International Edition N2 - The NHC-stabilised diboryne (B\(_2\)(SIDep)\(_2\); SIDep=1,3-bis(2,6-diethylphenyl)imidazolin-2-ylidene) undergoes a high-yielding P−P bond activation with tetraethyldiphosphine at room temperature to form a B\(_2\)P\(_2\) heterocycle via a diphosphoryldiborene by 1,2-diphosphination. The heterocycle can be oxidised to a radical cation and a dication, respectively, depending on the oxidant used and its counterion. Starting from the planar, neutral 1,3-bis(alkylidene)-1,3-diborata-2,4-diphosphoniocyclobutane, each oxidation step leads to decreased B−B distances and loss of planarity by cationisation. X-ray analyses in conjunction with DFT and CASSCF/NEVPT2 calculations reveal closed-shell singlet, butterfly-shaped structures for the NHC-stabilised dicationic B\(_2\)P\(_2\) rings, with their diradicaloid, planar-ring isomers lying close in energy. KW - inorganic chemistry KW - radicals KW - boron KW - density functional calculations KW - oxidation KW - phosphorus heterocycles Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256451 VL - 60 IS - 24 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 - Tetraiododiborane(4) (B\(_2\)I\(_4\)) is a Polymer based on sp\(^3\) Boron in the Solid State JF - Angewandte Chemie International Edition N2 - Herein we present the first solid‐state structures of tetraiododiborane(4) (B\(_2\)I\(_4\)), which was long believed to exist in all phases as discrete molecules with planar, tricoordinate boron atoms, like the lighter tetrahalodiboranes(4) B\(_2\)F\(_4\), B\(_2\)Cl\(_4\), and B\(_2\)Br\(_4\). Single‐crystal X‐ray diffraction, solid‐state NMR, and IR measurements indicate that B\(_2\)I\(_4\) in fact exists as two different polymeric forms in the solid state, both of which feature boron atoms in tetrahedral environments. DFT calculations are used to simulate the IR spectra of the solution and solid‐state structures, and these are compared with the experimental spectra. KW - boron tetraiodide KW - boron KW - density functional theory KW - diborane KW - halides KW - solid-state sturcture Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-209428 VL - 59 ER - TY - JOUR A1 - Cui, Jingjing A1 - Dietz, Maximilian A1 - Härterich, Marcel A1 - Fantuzzi, Felipe A1 - Lu, Wei A1 - Dewhurst, Rian D. A1 - Braunschweig, Holger T1 - Diphosphino-Functionalized 1,8-Naphthyridines: a Multifaceted Ligand Platform for Boranes and Diboranes JF - Chemistry—A European Journal N2 - A 1,8-naphthyridine diphosphine (NDP) reacts with boron-containing Lewis acids to generate complexes featuring a number of different naphthyridine bonding modes. When exposed to diborane B\(_{2}\)Br\(_{4}\), NDP underwent self-deprotonation to afford [NDP-B\(_{2}\)Br\(_{3}\)]Br, an unsymmetrical diborane comprised of four fused rings. The reaction of two equivalents of monoborane BBr\(_{3}\) and NDP in a non-polar solvent provided the simple phosphine-borane adduct [NDP(BBr\(_{3}\))\(_{2}\)], which then underwent intramolecular halide abstraction to furnish the salt [NDP-BBr\(_{2}\)][BBr\(_{4}\)], featuring a different coordination mode from that of [NDP-B\(_{2}\)Br\(_{3}\)]Br. Direct deprotonation of NDP by KHMDS or PhCH2K generates mono- and dipotassium reagents, respectively. The monopotassium reagent reacts with one or half an equivalent of B\(_{2}\)(NMe\(_{2}\))\(_{2}\)Cl\(_{2}\) to afford NDP-based diboranes with three or four amino substituents. KW - pincer ligand KW - potassium reagent KW - diborane KW - naphthyridine KW - boron Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256994 VL - 27 IS - 63 ER - TY - JOUR A1 - Hagspiel, Stephan A1 - Fantuzzi, Felipe A1 - Dewhurst, Rian D. A1 - Gärtner, Annalena A1 - Lindl, Felix A1 - Lamprecht, Anna A1 - Braunschweig, Holger T1 - Adducts of the parent boraphosphaketene H\(_2\)BPCO and their decarbonylative insertion chemistry JF - Angewandte Chemie International Edition N2 - The first examples of Lewis base adducts of the parent boraphosphaketene (H\(_2\)B-PCO) and their cyclodimers are prepared. One of these adducts is shown to undergo mild decarbonylation and phosphinidene insertion into a B−C bond of a borole, forming very rare examples of 1,2-phosphaborinines, B/P isosteres of benzene. The strong donor properties of these 1,2-phosphaborinines are confirmed by the synthesis of their π complexes with the Group 6 metals. KW - inorganic chemistry KW - phosphorus KW - boron KW - decarbonylation KW - heterocycles KW - ketenes Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256470 VL - 60 IS - 24 ER -