• Deutsch
  • Home
  • Search
  • Browse
  • Publish
  • Help
Schließen

Refine

Has Fulltext

  • yes (31)

Is part of the Bibliography

  • yes (31)

Year of publication

  • 2021 (7)
  • 2020 (6)
  • 2019 (3)
  • 2018 (4)
  • 2017 (8)
  • 2016 (3)

Document Type

  • Preprint (16)
  • Journal article (15)

Language

  • English (28)
  • German (3)

Keywords

  • boron (12)
  • diborenes (7)
  • carbenes (6)
  • Boron (4)
  • diborene (3)
  • Aromaticity (2)
  • Biradicals (2)
  • Cycloaddition (2)
  • Diborane (2)
  • EDA-NOCV (2)
+ more

Author

  • Arrowsmith, Merle (31)
  • Braunschweig, Holger (31)
  • Böhnke, Julian (12)
  • Hermann, Alexander (8)
  • Fantuzzi, Felipe (7)
  • Krummenacher, Ivo (7)
  • Vargas, Alfredo (7)
  • Auerhammer, Dominic (4)
  • Dellermann, Theresa (4)
  • Dewhurst, Rian D. (4)
+ more

Institute

  • Institut für Anorganische Chemie (31)
  • Institut für Physikalische und Theoretische Chemie (2)

Sonstige beteiligte Institutionen

  • Institute for Sustainable Chemistry & Catalysis with Boron (1)
  • The Chinese University of Hong Kong (1)
  • The University of Sussex (1)

EU-Project number / Contract (GA) number

  • 669054 (22)

31 search hits

  • 1 to 10
  • BibTeX
  • CSV
  • RIS
  • XML
  • 10
  • 20
  • 50
  • 100

Sort by

  • Year
  • Year
  • Title
  • Title
  • Author
  • Author
Highly colored boron-doped thiazolothiazoles from the reductive dimerization of boron isothiocyanates (2021)
Hagspiel, Stephan ; Arrowsmith, Merle ; Fantuzzi, Felipe ; Vargas, Alfredo ; Rempel, Anna ; Hermann, Alexander ; Brückner, Tobias ; Braunschweig, Holger
Reduction of (CAAC)BBr\(_2\)(NCS) (CAAC=cyclic alkyl(amino)carbene) in the presence of a Lewis base L yields tricoordinate (CAAC)LB(NCS) borylenes which undergo reversible E/Z-isomerization. The same reduction in the absence of L yields deep blue, bis(CAAC)-stabilized, boron-doped, aromatic thiazolothiazoles resulting from the dimerization of dicoordinate (CAAC)B(NCS) borylene intermediates.
Probing the Boundaries between Lewis-Basic and Redox Behavior of a Parent Borylene (2021)
Arrowsmith, Merle ; Endres, Sara ; Heinz, Myron ; Nestler, Vincent ; Holthausen, Max C. ; Braunschweig, Holger
The parent borylene (CAAC)(Me\(_{3}\)P)BH, 1 (CAAC=cyclic alkyl(amino)carbene), acts both as a Lewis base and one-electron reducing agent towards group 13 trichlorides (ECl\(_{3}\), E=B, Al, Ga, In), yielding the adducts 1-ECl\(_{3}\) and increasing proportions of the radical cation [1]\(^{•+}\) for the heavier group 13 analogues. With boron trihalides (BX\(_{3}\), X=F, Cl, Br, I) 1 undergoes sequential adduct formation and halide abstraction reactions to yield borylboronium cations and shows an increasing tendency towards redox processes for the heavier halides. Calculations confirm that 1 acts as a strong Lewis base towards EX3 and show a marked increase in the B−E bond dissociation energies down both group 13 and the halide group.
Nucleophilic addition and substitution at coordinatively saturated boron by facile 1,2-hydrogen shuttling onto a carbene donor (2017)
Auerhammer, Dominic ; Arrowsmith, Merle ; Braunschweig, Holger ; Dewhurst, Rian D. ; Jiménez-Halla, J. Oscar C. ; Kupfer, Thomas
The reaction of [(cAAC\(^{Me}\))BH\(_{3}\)] (cAAC\(^{Me}\) = 1-(2,6-iPr\(_{2}\)C\(_{6}\)H\(_{3}\))-3,3,5,5-tetramethylpyrrolidin-2-ylidene) with a range of organolithium compounds led to the exclusive formation of the corresponding (dihydro)organoborates, Li\(^{+}\)[(cAAC\(^{Me}\)H)BH\(_{2}\)R]− (R = sp\(^{3}\)-, sp\(^{2}\)-, or sp-hybridised organic substituent), by migration of one boron-bound hydrogen atom to the adjacent carbene carbon of the cAAC ligand. A subsequent deprotonation/salt metathesis reaction with Me3SiCl or spontaneous LiH elimination yielded the neutral cAAC-supported mono(organo)boranes, [(cAAC\(^{Me}\)H)BH\(_{2}\)R]− (R]. Similarly the reaction of [cAAC\(^{Me}\))BH\(_{3}\)] with a neutral donor base L resulted in adduct formation by shuttling one boron-bound hydrogen to the cAAC ligand, to generate [(cAAC\(^{Me}\)H)BH\(_{2}\)L], either irreversibly (L = cAAC\(^{Me}\)) or reversibly (L = pyridine). Variable-temperature NMR data and DFT calculations on [(cAAC\(^{Me}\)H)BH\(_{2}\)(cAAC\(^{Me}\))] show that the hydrogen on the former carbene carbon atom exchanges rapidly with the boron-bound hydrides.
Boron- versus Nitrogen-Centered Nucleophilic Reactivity of (Cyano)hydroboryl Anions: Synthesis of Cyano(hydro)organoboranes and 2-Aza-1,4-diborabutatrienes (2021)
Gärtner, Annalena ; Marek, Matthäus ; Arrowsmith, Merle ; Auerhammer, Dominic ; Radacki, Krzysztof ; Prieschl, Dominic ; Dewhurst, Rian D. ; Braunschweig, Holger
Cyclic alkyl(amino)carbene-stabilized (cyano)hydroboryl anions were synthesized by deprotonation of (cyano)dihydroborane precursors. While they display boron-centered nucleophilic reactivity towards organohalides, generating fully unsymmetrically substituted cyano(hydro)organoboranes, they show cyano-nitrogen-centered nucleophilic reactivity towards haloboranes, resulting in the formation of hitherto unknown linear 2-aza-1,4-diborabutatrienes.
A neutral beryllium(I) radical (2021)
Czernetzki, Corinna ; Arrowsmith, Merle ; Fantuzzi, Felipe ; Gärtner, Annalena ; Tröster, Tobias ; Krummenacher, Ivo ; Schorr, Fabian ; Braunschweig, Holger
The reduction of a cyclic alkyl(amino)carbene (CAAC)-stabilized organoberyllium chloride yields the first neutral beryllium radical, which was characterized by EPR, IR, UV/Vis spectroscopy and X-ray crystallography. DFT calculations show significant spin density at beryllium and confirm donor–acceptor bonding between an alkylberyllium radical fragment and a neutral CAAC ligand.
Neutral Diboron Analogues of Archetypal Aromatic Species by Spontaneous Cycloaddition (2016)
Arrowsmith, Merle ; Böhnke, Julian ; Braunschweig, Holger ; Celik, Mehmet ; Claes, Christina ; Ewing, William ; Krummenacher, Ivo ; Lubitz, Katharina ; Schneider, Christoph
Among the numerous routes organic chemists have developed to synthesize benzene derivatives and heteroaro- matic compounds, transition-metal-catalyzed cycloaddition reactions are the most elegant. In contrast, cycloaddition reactions of heavier alkene and alkyne analogues, though limited in scope, proceed uncatalyzed. In this work we present the first spontaneous cycloaddition reactions of lighter alkene and alkyne analogues. Selective addition of unactivated alkynes to boron–boron multiple bonds under ambient con- ditions yielded diborocarbon equivalents of simple aromatic hydrocarbons, including the first neutral 6 π-aromatic dibora- benzene compound, a 2  π-aromatic triplet biradical 1,3-dibor- ete, and a phosphine-stabilized 2  π-homoaromatic 1,3-dihydro- 1,3-diborete. DFT calculations suggest that all three com- pounds are aromatic and show frontier molecular orbitals matching those of the related aromatic hydrocarbons, C\(_6\)H\(_6\) and C\(_4\)H\(_4\)\(^{2+}\), and homoaromatic C\(_4\)H\(_5\)\(^+\).
Uncatalyzed Hydrogenation of First-Row Main Group Multiple Bonds (2016)
Arrowsmith, Merle ; Böhnke, Julian ; Braunschweig, Holger ; Celik, Mehmet ; Dellermann, Theresa ; Hammond, Kai
Room temperature hydrogenation of an SIDep-stabilized diboryne (SIDep = 1,3-bis(diethylphenyl)-4,5-dihydroimidazol-2-ylidene) and a CAAC-supported diboracumulene (CAAC = 1-(2,6- diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) provided the first selective route to the corresponding 1,2-dihydrodiborenes. DFT calculations showed an overall exothermic (ΔG = 19.4 kcal mol\(^{-1}\) two-step asynchronous H\(_2\) addition mechanism proceeding via a bridging hydride.
Increasing the Reactivity of Diborenes: Derivatization of NHC- Supported Dithienyldiborenes with Electron-Donor Groups (2017)
Auerhammer, Dominic ; Arrowsmith, Merle ; Bissinger, Philipp ; Braunschweig, Holger ; Dellermann, Theresa ; Kupfer, Thomas ; Lenczyk, Carsten ; Roy, Dipak ; Schäfer, Marius ; Schneider, Christoph
A series of NHC-supported 1,2-dithienyldiborenes was synthesized from the corresponding (dihalo)thienylborane NHC precursors. NMR and UV-vis spectroscopic data, as well as X-ray crystallographic analyses, were used to assess the electronic and steric influences on the B=B double bond of various NHCs and electron-donating substituents on the thienyl ligands. Crystallographic data showed that the degree of coplanarity of the diborene core and thienyl groups is highly dependent on the sterics of the substituents. Furthermore, any increase in the electron- donating ability of the substituents resulted in the destabilization of the HOMO and greater instability of the resulting diborenes.
Brothers from Another Mother: a Borylene and its Dimer are Non-Interconvertible but Connected through Reactivity (2018)
Auerhammer, Dominic ; Arrowsmith, Merle ; Böhnke, Julian ; Braunschweig, Holger ; Dewhurst, Rian D. ; Kupfer, Thomas
The self-stabilizing, tetrameric cyanoborylene [(cAAC)B(CN)]4 (I, cAAC = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) and its diborene relative, [(cAAC)(CN)B=B(CN)(cAAC)] (II), both react with disulfides and diselenides to yield the corresponding cAAC-supported cyanoboron bis(chalcogenides). Furthermore, reactions of I or II with elemental sulfur and selenium in various stoichiometries provided access to a variety of cAAC- stabilized cyanoboron-chalcogen heterocycles, including a unique dithiaborirane, a diboraselenirane, 1,3-dichalcogena-2,4-diboretanes, 1,3,4-trichalcogena- 2,5-diborolanes and a rare six-membered 1,2,4,5-tetrathia-3,6-diborinane. Stepwise addition reactions and solution stability studies provided insights into the mechanism of these reactions and the subtle differences in reactivity observed between I and II.
Direct access to a cAAC-supported dihydrodiborene and its dianion (2018)
Arrowsmith, Merle ; Mattock, James D. ; Böhnke, Julian ; Krummenacher, Ivo ; Vargas, Alfredo ; Braunschweig, Holger
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.
  • 1 to 10

DINI-Zertifikat     OPUS4 Logo

  • Contact
  • |
  • Imprint
  • |
  • Sitemap