@unpublished{HermannArrowsmithTrujilloGonzalezetal.2020,
  author    = {Hermann, Alexander and Arrowsmith, Merle and Trujillo-Gonzalez, Daniel and Jim{\´e}nez-Halla, J. Oscar C. and Vargas, Alfredo and Braunschweig, Holger},
  title     = {Trapping of a Borirane Intermediate in the Reductive Coupling of an Arylborane to a Diborene},
  series = {Journal of the American Chemical Society},
  journal   = {Journal of the American Chemical Society},
  doi       = {10.1021/jacs.0c02306},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-203140},
  year      = {2020},
  abstract  = {The reductive coupling of an NHC-stabilized aryldibromoborane yields a mixture of trans- and cis-diborenes in which the aryl groups are coplanar with the diborene core. Under dilute reduction conditions two diastereomers of a borirane-borane intermediate are isolated, which upon further reduction give rise to the aforementioned diborene mixture. DFT calculations suggest a mechanism proceeding via nucleophilic attack of a dicoordinate borylene intermediate on the aryl ring and subsequent intramolecular B-B bond formation.},
  language  = {en}
}
@unpublished{BruecknerStennettHessetal.2019,
  author    = {Br{\"u}ckner, Tobias and Stennett, Tom E. and Heß, Merlin and Braunschweig, Holger},
  title     = {Single and Double Hydroboration of B-B Triple Bonds and Conver- gent Routes to a Cationic Tetraborane},
  series = {Journal of the American Chemical Society},
  journal   = {Journal of the American Chemical Society},
  doi       = {10.1021/jacs.9b07991},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188632},
  year      = {2019},
  abstract  = {A compound with a boron-boron triple bond is shown to undergo stepwise hydroboration reactions with catecholborane to yield an unsymmetrical hydro(boryl)diborene and a 2,3-dihydrotetraborane. Abstraction of H- from the latter compound produces an unusual cationic, planar tetraborane with a hydrogen atom bridging the central B2 moiety. Spectroscopic and crystallographic data and DFT calculations support a 'protonated diborene' structure for this compound, which can also be accessed via direct protonation of the corresponding diborene.},
  language  = {en}
}
@unpublished{LegarePranckeviciusBraunschweig2019,
  author    = {L{\´e}gar{\´e}, Marc-Andr{\´e} and Pranckevicius, Conor and Braunschweig, Holger},
  title     = {Metallomimetic Chemistry of Boron},
  series = {Chemical Reviews},
  journal   = {Chemical Reviews},
  doi       = {10.1021/acs.chemrev.8b00561},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-186317},
  year      = {2019},
  abstract  = {The study of main-group molecules that behave and react similarly to transition-metal (TM) complexes has attracted significant interest in recent decades. Most notably, the attractive idea of replacing the all-too-often rare and costly metals from catalysis has motivated efforts to develop main-group-element-mediated reactions. Main-group elements, however, lack the electronic flexibility of TM complexes that arises from combinations of empty and filled d orbitals and that seem ideally suited to bind and activate many substrates. In this review, we look at boron, an element that despite its nonmetal nature, low atomic weight, and relative redox staticity has achieved great milestones in terms of TM-like reactivity. We show how in interelement cooperative systems, diboron molecules, and hypovalent complexes the fifth element can acquire a truly metallomimetic character. As we discuss, this character is powerfully demonstrated by the reactivity of boron-based molecules with H2, CO, alkynes, alkenes and even with N2.},
  language  = {en}
}
@unpublished{BruecknerArrowsmithHessetal.2019,
  author    = {Br{\"u}ckner, Tobias and Arrowsmith, Merle and Heß, Merlin and Hammond, Kai and M{\"u}ller, Marcel and Braunschweig, Holger},
  title     = {Synthesis of fused B,N-heterocycles by alkyne cleavage, NHC ring-expansion and C-H activation at a diboryne},
  series = {Chemical Communications},
  journal   = {Chemical Communications},
  doi       = {10.1039/C9CC02657F},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-184899},
  year      = {2019},
  abstract  = {The addition of alkynes to a staturated N-heterocyclic carbene (NHC)-supported diboryne results in spontaneous cycloaddition, with complete B≡B and C≡C triple bond cleavage, NHC ring- expansion and activation of a variety of C-H bonds, leading to the formation of complex mixtures of fused B,N-heterocycles.},
  language  = {en}
}
@unpublished{StennettBissingerGriesbecketal.2019,
  author    = {Stennett, Tom E. and Bissinger, Philipp and Griesbeck, Stefanie and Ullrich, Stefan and Krummenacher, Ivo and Auth, Michael and Sperlich, Andreas and Stolte, Matthias and Radacki, Krzysztof and Yao, Chang-Jiang and W{\"u}rthner, Frank and Steffen, Andreas and Marder, Todd B. and Braunschweig, Holger},
  title     = {Near-Infrared Quadrupolar Chromophores Combining Three-Coordinate Boron-Based Superdonor and Superacceptor Units},
  series = {Angewandte Chemie, International Edition},
  journal   = {Angewandte Chemie, International Edition},
  doi       = {10.1002/anie.201900889},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-180391},
  year      = {2019},
  abstract  = {In this work, two new quadrupolar A-π-D-π-A chromophores have been prepared featuring a strongly electron- donating diborene core and strongly electron-accepting dimesitylboryl F(BMes2) and bis(2,4,6-tris(trifluoromethyl)phenyl)boryl (BMes2) end groups. Analysis of the compounds by NMR spectroscopy, X-ray crystallography, cyclic voltammetry and UV-vis-NIR absorption and emission spectroscopy indicated that the compounds possess extended conjugated π-systems spanning their B4C8 cores. The combination of exceptionally potent π-donor (diborene) and π- acceptor (diarylboryl) groups, both based on trigonal boron, leads to very small HOMO-LUMO gaps, resulting in strong absorption in the near-IR region with maxima in THF at 840 and 1092 nm, respectively, and very high extinction coefficients of ca. 120,000 M-1cm-1. Both molecules also display weak near-IR fluorescence with small Stokes shifts.},
  language  = {en}
}
@unpublished{MuessigThalerDewhurstetal.2019,
  author    = {Muessig, Jonas H. and Thaler, Melanie and Dewhurst, Rian D. and Paprocki, Valerie and Seufert, Jens and Mattock, James D. and Vargas, Alfredo and Braunschweig, Holger},
  title     = {Phosphine-Stabilized Diiododiborenes: Isolable Diborenes with Six Labile Bonds},
  series = {Angewandte Chemie, International Edition},
  journal   = {Angewandte Chemie, International Edition},
  doi       = {10.1002/anie.201814230},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178608},
  year      = {2019},
  abstract  = {The lability of B=B, B-P and B-halide bonds is combined in the syntheses of the first diiododiborenes. In a series of reactivity tests, these diiododiborenes demonstrate cleavage of all six of their central bonds in different ways, leading to products of B=B hydrogenation and dihalogenation as well as halide exchange.},
  language  = {en}
}
@unpublished{StennettMattockPentecostetal.2018,
  author    = {Stennett, Tom and Mattock, James and Pentecost, Leanne and Vargas, Alfredo and Braunschweig, Holger},
  title     = {Chelated Diborenes and their Inverse-Electron-Demand Diels- Alder Reactions with Dienes},
  series = {Angewandte Chemie, International Edition},
  journal   = {Angewandte Chemie, International Edition},
  doi       = {10.1002/anie.201809217},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178268},
  year      = {2018},
  abstract  = {A doubly base-stabilized diborane based on a benzylphosphine linker was prepared by a salt elimination reaction between 2-LiC\(_6\)H\(_4\)CH\(_2\)PCy\(_2\).Et\(_2\)O and B\(_2\)Br\(_4\). This compound was reduced with KC8 to its corresponding diborene, with the benzylphosphine forming a five-membered chelate. The diborene reacts with butadiene, 2-trimethylsiloxy-1,3-butadiene and isoprene to form 4,5-diboracyclohexenes, which interconvert between their 1,1- (geminal) and 1,2- (vicinal) chelated isomers. The 1,1-chelated diborene undergoes a halide-catalysed isomerisation into its thermodynamically favoured 1,2-isomer, which undergoes Diels-Alder reactions more slowly than the kinetic product.},
  language  = {en}
}
@unpublished{StennettBertermannBraunschweig2018,
  author    = {Stennett, Tom and Bertermann, R{\"u}diger and Braunschweig, Holger},
  title     = {Construction of Linear and Branched Tetraboranes via 1,1- and 1,2-Diboration of Diborenes},
  series = {Angewandte Chemie, International Edition},
  journal   = {Angewandte Chemie, International Edition},
  doi       = {10.1002/anie.201809976},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178276},
  year      = {2018},
  abstract  = {Sterically unencumbered diborenes based on a benzylphosphine chelate undergo diboration reactions with bis(catecholato)diboron in the absence of a catalyst to yield tetraboranes. The symmetrical diborenes studied undergo 1,2- diborations, whereas an unsymmetrical derivative was found to yield a triborylborane-phosphine adduct as the result of a formal 1,1-diboration. A related borylborylene compound also underwent a 1,2-diboration to produce a borylene-borane adduct.},
  language  = {en}
}
@unpublished{BoehnkeArrowsmithBraunschweig2018,
  author    = {B{\"o}hnke, Julian and Arrowsmith, Merle and Braunschweig, Holger},
  title     = {Activation of a Zerovalent Diboron Compound by Desymmetrization},
  series = {Journal of the American Chemical Society},
  journal   = {Journal of the American Chemical Society},
  doi       = {10.1021/jacs.8b06930},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167983},
  year      = {2018},
  abstract  = {The desymmetrization of the cyclic (alkyl)(amino)carbene-supported diboracumulene, B\(_2\)(cAAC\(^{Me}\))\(_2\) (cAAC\(^{Me}\) = 1- (2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) by mono-adduct formation with IMe\(^{Me}\) (1,3-dimethylimidazol-2-ylidene) yields the zerovalent sp-sp\(^2\) diboron compound B\(_2\)(cAAC\(^{Me}\))\(_2\)(IMe\(^{Me}\)), which provides a versatile platform for the synthesis of novel symmetrical and unsymmetrical zerovalent sp\(^2\)-sp\(^2\) diboron compounds by adduct formation with IMe\(^{Me}\) and CO, respectively. Furthermore, B\(_2\)(cAAC\(^{Me}\))\(_2\)(IMe\(^{Me}\)) displays enhanced reactivity compared to its symmetrical precursor, undergoing spontaneous intramolecular C-H activation and facile twofold hydrogenation, the latter resulting in B-B bond cleavage and the formation of the mixed-base parent borylene, (cAAC\(^{Me}\))(IMe\(^{Me}\))BH.},
  language  = {en}
}
@unpublished{StoyBoehnkeJiménezHallaetal.2018,
  author    = {Stoy, Andreas and B{\"o}hnke, Julian and Jiménez-Halla, J. Oscar C. and Dewhurst, Rian D. and Thiess, Torsten and Braunschweig, Holger},
  title     = {CO\(_2\) Binding and Splitting by Boron-Boron Multiple Bonds},
  series = {Angewandte Chemie, International Edition},
  journal   = {Angewandte Chemie, International Edition},
  doi       = {10.1002/anie.201802117},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164265},
  year      = {2018},
  abstract  = {CO\(_2\) is found to undergo room-temperature, ambient- pressure reactions with two species containing boron-boron multiple bonds, leading to incorporation of either one or two CO\(_2\) molecules. In one case, a thermally-unstable intermediate was structurally characterized, indicating the operation of an initial 2+2 cycloaddition mechanism in the reaction.},
  language  = {en}
}