@unpublished{WangArrowsmithBoehnkeetal.2017, author = {Wang, Sunewang R. and Arrowsmith, Merle and B{\"o}hnke, Julian and Braunschweig, Holger and Dellermann, Theresa and Dewhurst, Rian D. and Kelch, Hauke and Krummenacher, Ivo and Mattock, James D. and M{\"u}ssig, Jonas H. and Thiess, Torsten and Vargas, Alfredo and Zhang, Jiji}, title = {Engineering a Small HOMO-LUMO Gap and Intramolecular B-B Hydroarylation by Diborene/Anthracene Orbital Intercalation}, series = {Angewandte Chemie, International Edition}, volume = {56}, journal = {Angewandte Chemie, International Edition}, number = {27}, doi = {10.1002/anie.201704063}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148126}, pages = {8009-8013}, year = {2017}, abstract = {The diborene 1 was synthesized by reduction of a mixture of 1,2-di-9-anthryl-1,2-dibromodiborane(4) (6) and trimethylphosphine with potassium graphite. The X-ray structure of 1 shows the two anthryl rings to be parallel and their π(C\(_{14}\)) systems perpendicular to the diborene π(B=B) system. This twisted conformation allows for intercalation of the relatively high-lying π(B=B) orbital and the low-lying π* orbital of the anthryl moiety with no significant conjugation, resulting in a small HOMO-LUMO gap (HLG) and ultimately an unprecedented anthryl B-B bond hydroarylation. The HLG of 1 was estimated to be 1.57 eV from the onset of the long wavelength band in its UV-vis absorption spectrum (THF, λ\(_{onset}\) = 788 nm). The oxidation of 1 with elemental selenium afforded diboraselenirane 8 in quantitative yield. By oxidative abstraction of one phosphine ligand by another equivalent of elemental selenium, the B-B and C\(^1\)-H bonds of 8 were cleaved to give the cyclic 1,9-diboraanthracene 9.}, language = {en} } @unpublished{HermannCidMattocketal.2018, author = {Hermann, Alexander and Cid, Jessica and Mattock, James D. and Dewhurst, Rian D. and Krummenacher, Ivo and Vargas, Alfredo and Ingleson, Michael J. and Braunschweig, Holger}, title = {Diboryldiborenes: π-Conjugated B\(_4\) Chains Isoelectronic to the Butadiene Dication}, series = {Angewandte Chemie, International Edition}, journal = {Angewandte Chemie, International Edition}, doi = {10.1002/anie.201805394}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167977}, year = {2018}, abstract = {sp\(^2\)-sp\(^3\) diborane species based on bis(catecholato)diboron and N-heterocyclic carbenes (NHCs) are subjected to catechol/bromide exchange selectively at the sp\(^3\) boron atom. The reduction of the resulting 1,1-dibromodiborane adducts led to reductive coupling and isolation of doubly NHC-stabilized 1,2-diboryldiborenes. These compounds are the first examples of molecules exhibiting pelectron delocalization over an all-boron chain.}, 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} } @article{EwingDellermannAngelWongetal.2020, author = {Ewing, William C. and Dellermann, Theresa and Angel Wong, Y. T. and Mattock, James D. and Vargas, Alfredo and Bryce, David L. and Dewhurst, Rian D. and Braunschweig, Holger}, title = {\(\pi\)-Complexes of Diborynes with Main Group Atoms}, series = {Chemistry - An Asian Journal}, volume = {15}, journal = {Chemistry - An Asian Journal}, number = {10}, doi = {10.1002/asia.202000185}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-214677}, pages = {1553 -- 1557}, year = {2020}, abstract = {We present herein an in-depth study of complexes in which a molecule containing a boron-boron triple bond is bound to tellurate cations. The analysis allows the description of these salts as true π complexes between the B-B triple bond and the tellurium center. These complexes thus extend the well-known Dewar-Chatt-Duncanson model of bonding to compounds made up solely of p block elements. Structural, spectroscopic and computational evidence is offered to argue that a set of recently reported heterocycles consisting of phenyltellurium cations complexed to diborynes bear all the hallmarks of \(\pi\)-complexes in the \(\pi\)-complex/metallacycle continuum envisioned by Joseph Chatt. Described as such, these compounds are unique in representing the extreme of a metal-free continuum with conventional unsaturated three-membered rings (cyclopropenes, azirenes, borirenes) occupying the opposite end.}, language = {en} } @unpublished{ArrowsmithMattockBoehnkeetal.2018, author = {Arrowsmith, Merle and Mattock, James D. and B{\"o}hnke, Julian and Krummenacher, Ivo and Vargas, Alfredo and Braunschweig, Holger}, title = {Direct access to a cAAC-supported dihydrodiborene and its dianion}, series = {Chemical Communications}, journal = {Chemical Communications}, doi = {10.1039/C8CC01580E}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164276}, year = {2018}, abstract = {The two-fold reduction of (cAAC)BHX\(_2\) (cAAC = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene; X = Cl, Br) provides a facile, high-yielding route to the dihydrodiborene (cAAC)\(_2\)B\(_2\)H\(_2\). The (chloro)hydroboryl anion reduction intermediate was successfully isolated using a crown ether. Overreduction of the diborene to its dianion [(cAAC)\(_2\)B\(_2\)H\(_2\)]\(^{2-}\) causes a decrease in the B-B bond order whereas the B-C bond orders increase.}, language = {en} } @article{BraunschweigEwingGhoshetal.2016, author = {Braunschweig, Holger and Ewing, William C. and Ghosh, Sundargopal and Kramer, Thomas and Mattock, James D. and {\"O}streicher, Sebastian and Vargas, Alfredo and Werner, Christine}, title = {Trimetallaborides as starting points for the syntheses of large metal-rich molecular borides and clusters}, series = {Chemical Science}, volume = {7}, journal = {Chemical Science}, number = {1}, doi = {10.1039/c5sc03206g}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-191511}, pages = {109-116}, year = {2016}, abstract = {Treatment of an anionic dimanganaborylene complex ([{Cp(CO)\(_2\)Mn}\(_2\)B]\(^-\)) with coinage metal cations stabilized by a very weakly coordinating Lewis base (SMe\(_2\)) led to the coordination of the incoming metal and subsequent displacement of dimethylsulfide in the formation of hexametalladiborides featuring planar four-membered M\(_2\)B\(_2\) cores (M = Cu, Au) comparable to transition metal clusters constructed around four-membered rings composed solely of coinage metals. The analogies between compounds consisting of B\(_2\)M\(_2\) units and M\(_4\) (M = Cu, Au) units speak to the often overlooked metalloid nature of boron. Treatment of one of these compounds (M = Cu) with a Lewis-basic metal fragment (Pt(PCy\(_3\))\(_2\)) led to the formation of a tetrametallaboride featuring two manganese, one copper and one platinum atom, all bound to boron in a geometry not yet seen for this kind of compound. Computational examination suggests that this geometry is the result of d\(^{10}\)-d\(^{10}\) dispersion interactions between the copper and platinum fragments.}, language = {en} } @article{SchmidtWernerArrowsmithetal.2020, author = {Schmidt, Uwe and Werner, Luis and Arrowsmith, Merle and Deissenberger, Andrea and Hermann, Alexander and Hofmann, Alexander and Ullrich, Stefan and Mattock, James D. and Vargas, Alfredo and Braunschweig, Holger}, title = {Trans-selektive Dihydroborierung eines cis-Diborens durch Insertion: Synthese eines linearen sp\(^3\)-sp\(^2\)-sp\(^3\)-Triborans und anschließende Kationisierung}, series = {Angewandte Chemie}, volume = {132}, journal = {Angewandte Chemie}, number = {1}, doi = {10.1002/ange.201911645}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-219713}, pages = {333-337}, year = {2020}, abstract = {Die Reaktion zwischen Aryl- und Amino(dihydro)boranen und Dibora[2]ferrocenophan 1 f{\"u}hrt zur Bildung von 1,3-trans-Dihydrotriboranen durch formale Hydrierung und Insertion eines Borylens in die B=B Doppelbindung. Die Aryltriboran-Derivate unterliegen einer reversiblen Photoisomerisierung zugunsten eines cis-1,2-μ-H-3-Hydrotriborans, w{\"a}hrend eine Hydridabstraktion zu kationischen Triboranen f{\"u}hrt, welche die ersten doppelt basenstabilisierten B\(_3\)H\(_4\)\(^+\)-Analoga darstellen.}, language = {de} } @article{SchmidtWernerArrowsmithetal.2020, author = {Schmidt, Uwe and Werner, Luis and Arrowsmith, Merle and Deissenberger, Andrea and Hermann, Alexander and Hofmann, Alexander and Ullrich, Stefan and Mattock, James D. and Vargas, Alfredo and Braunschweig, Holger}, title = {trans-Selective Insertional Dihydroboration of a cis-Diborene: Synthesis of Linear sp\(^3\)-sp\(^2\)-sp\(^3\)-Triboranes and Subsequent Cationization}, series = {Angewandte Chemie International Edition}, volume = {59}, journal = {Angewandte Chemie International Edition}, number = {1}, doi = {10.1002/anie.201911645}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-208090}, pages = {325-329}, year = {2020}, abstract = {The reaction of aryl- and amino(dihydro)boranes with dibora[2]ferrocenophane 1 leads to the formation 1,3-trans -dihydrotriboranes by formal hydrogenation and insertion of a borylene unit into the B=B bond. The aryltriborane derivatives undergo reversible photoisomerization to the cis -1,2-μ-H-3-hydrotriboranes, while hydride abstraction affords cationic triboranes, which represent the first doubly base-stabilized B3H4\(^+\) analogues.}, language = {en} }