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 - Brückner, Tobias A1 - Dewhurst, Rian D. A1 - Dellermann, Theresa A1 - Müller, Marcel A1 - Braunschweig, Holger T1 - Mild synthesis of diboryldiborenes by diboration of B–B triple bonds JF - Chemical Science N2 - A set of diboryldiborenes are prepared by the mild, catalyst-free, room-temperature diboration of the B–B triple bonds of doubly base-stabilized diborynes. Two of the product diboryldiborenes are found to be air- and water-stable in the solid state, an effect that is attributed to their high crystallinity and extreme insolubility in a wide range of solvents. KW - boron KW - diborenes KW - diboration KW - triple bonds KW - diborynes Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-186306 VL - 10 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 - Berger, Sarina M. A1 - Rühe, Jessica A1 - Schwarzmann, Johannes A1 - Phillipps, Alexandra A1 - Richard, Ann-Katrin A1 - Ferger, Matthias A1 - Krummenacher, Ivo A1 - Tumir, Lidija-Marija A1 - Ban, Željka A1 - Crnolatac, Ivo A1 - Majhen, Dragomira A1 - Barišić, Ivan A1 - Piantanida, Ivo A1 - Schleier, Domenik A1 - Griesbeck, Stefanie A1 - Friedrich, Alexandra A1 - Braunschweig, Holger A1 - Marder, Todd B. T1 - Bithiophene-Cored, mono-, bis-, and tris-(Trimethylammonium)-Substituted, bis-Triarylborane Chromophores: Effect of the Number and Position of Charges on Cell Imaging and DNA/RNA Sensing JF - Chemistry—A European Journal N2 - The synthesis, photophysical, and electrochemical properties of selectively mono-, bis- and tris-dimethylamino- and trimethylammonium-substituted bis-triarylborane bithiophene chromophores are presented along with the water solubility and singlet oxygen sensitizing efficiency of the cationic compounds Cat\(^{1+}\), Cat\(^{2+}\), Cat(i)\(^{2+}\), and Cat\(^{3+}\). Comparison with the mono-triarylboranes reveals the large influence of the bridging unit on the properties of the bis-triarylboranes, especially those of the cationic compounds. Based on these preliminary investigations, the interactions of Cat\(^{1+}\), Cat\(^{2+}\), Cat(i)\(^{2+}\), and Cat\(^{3+}\) with DNA, RNA, and DNApore were investigated in buffered solutions. The same compounds were investigated for their ability to enter and localize within organelles of human lung carcinoma (A549) and normal lung (WI38) cells showing that not only the number of charges but also their distribution over the chromophore influences interactions and staining properties. KW - singlet oxygen KW - boron KW - bioimaging KW - luminescence KW - nucleic acid Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256963 VL - 27 IS - 56 ER - TY - JOUR A1 - Bachmann, Jonas A1 - Helbig, Andreas A1 - Crumbach, Merian A1 - Krummenacher, Ivo A1 - Braunschweig, Holger A1 - Helten, Holger T1 - Fusion of Aza‐ and Oxadiborepins with Furans in a Reversible Ring‐Opening Process Furnishes Versatile Building Blocks for Extended π‐Conjugated Materials JF - Chemistry – A European Journal N2 - A modular synthesis of both difurooxa‐ and difuroazadiborepins from a common precursor is demonstrated. Starting from 2,2′‐bifuran, after protection of the positions 5 and 5’ with bulky silyl groups, formation of the novel polycycles proceeds through opening of the furan rings to a dialkyne and subsequent re‐cyclization in the borylation step. The resulting bifuran‐fused diborepins show pronounced stability, highly planar tricyclic structures, and intense blue light emission. Deprotection and transformation into dibrominated building blocks that can be incorporated into π‐extended materials can be performed in one step. Detailed DFT calculations provide information about the aromaticity of the constituent rings of this polycycle. KW - aromaticity KW - boron KW - BN compounds KW - furan KW - polycycles Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293926 VL - 28 IS - 63 ER - TY - JOUR A1 - Ansell, Melvyn B. A1 - Kostakis, George E. A1 - Braunschweig, Holger A1 - Navarro, Oscar A1 - Spencer, John T1 - Synthesis of functionalized hydrazines: facile homogeneous (N-heterocyclic carbene)-palladium(0)-catalyzed diboration and silaboration of azobenzenes JF - Advanced Synthesis & Catalysis N2 - The bis(N-heterocyclic carbene)(diphenylacetylene)palladium complex Pd(ITMe)\(_2\)(PhCCPh)] (ITMe=1,3,4,5-tetramethylimidazol-2-ylidene) acts as a highly active pre-catalyst in the diboration and silaboration of azobenzenes to synthesize a series of novel functionalized hydrazines. The reactions proceed using commercially available diboranes and silaboranes under mild reaction conditions. KW - Palladium-catalyzed silaboration KW - B-B bond KW - molecular-structure KW - terminal alkynes KW - crystal-structure KW - alkenes KW - complexes KW - mechanism KW - boron KW - design KW - azobenzenes KW - dilaboration KW - N-heterocyclic carbenes KW - palladium KW - silaboration Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-186582 VL - 358 IS - 23 ER -