@article{NeesKupferHofmannetal.2020,
  author    = {Nees, Samuel and Kupfer, Thomas and Hofmann, Alexander and Braunschweig, Holger},
  title     = {Stabilisierung planarer Cyclopenten-4-yl-Kationen durch Hyperkonjugation und π-Delokalisierung},
  series = {Angewandte Chemie},
  volume    = {132},
  journal   = {Angewandte Chemie},
  number    = {42},
  doi       = {10.1002/ange.202009644},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218456},
  pages     = {18971 -- 18978},
  year      = {2020},
  abstract  = {Theoretischen Untersuchungen zufolge stellt das planare Cyclopenten-4-yl-Kation das energetisch ung{\"u}nstigste C\(_{5}\)H\(_{7}\)\(^{+}\)-Isomer dar und ist am ehesten als klassisches Carbokation zu beschreiben, wobei dessen Existenz experimentell bislang noch nicht nachgewiesen werden konnte. Durch Umsetzung sterisch {\"u}berfrachteter Alane vom Typ Cp\(^{R}\)AlBr\(_{2}\) mit AlBr3 ist uns nun die Isolierung zweier stabiler Derivate des Cyclopenten-4-yl-Kations gelungen. Untersuchungen zu deren (elektronischer) Struktur (XRD, QM) offenbarten planare Geometrien und starke Hyperkonjugationswechselwirkungen zwischen den C-Al-σ-Bindungen und dem unbesetzten p-Orbital der kationischen sp\(^{2}\)-Kohlenstoffzentren. Die Analyse der Molek{\"u}lorbitale (MOs), der Anisotropie der induzierten Stromdichte (ACID) sowie verschiedener Aromatizit{\"a}tsdeskriptoren deuten hierbei auf ein hohes Maß an Delokalisierung und π-Aromatizit{\"a}t in diesen Systemen hin, was einer klassischen Beschreibung grundlegend widerspricht. Unsere Cyclopenten-4-yl-Kationen geh{\"o}ren somit zu den wenigen Beispielen aromatischer Carbocyclen, in denen eine Delokalisierung der π-Elektronen {\"u}ber ges{\"a}ttigte sp\(^{3}\)-Kohlenstoffatome hinweg beobachtet wird.},
  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-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}
}
@article{HermannFantuzziArrowsmithetal.2020,
  author    = {Hermann, Alexander and Fantuzzi, Felipe and Arrowsmith, Merle and Zorn, Theresa and Krummenacher, Ivo and Ritschel, Benedikt and Radacki, Krzysztof and Engels, Bernd and Braunschweig, Holger},
  title     = {Oxidation, Coordination, and Nickel-Mediated Deconstruction of a Highly Electron-Rich Diboron Analogue of 1,3,5-Hexatriene},
  series = {Angewandte Chemie, International Edition},
  volume    = {59},
  journal   = {Angewandte Chemie, International Edition},
  number    = {36},
  doi       = {10.1002/anie.202006131},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-240652},
  pages     = {15717-15725},
  year      = {2020},
  abstract  = {The reductive coupling of an N-heterocyclic carbene (NHC) stabilized (dibromo)vinylborane yields a 1,2-divinyl- diborene, which, although isoelectronic to a 1,3,5-triene, displays no extended p conjugation because of twisting of the C\(_2\)B\(_2\)C\(_2\) chain. While this divinyldiborene coordinates to copper(I) and platinum(0) in an η\(^2\)-B\(_2\) and η\(^4\)-C\(_2\)B\(_2\) fashion, respectively, it undergoes a complex rearrangement to an η\(^4\)-1,3-diborete upon complexation with nickel(0).},
  language  = {en}
}
@article{RauchEndresFriedrichetal.2020,
  author    = {Rauch, Florian and Endres, Peter and Friedrich, Alexandra and Sieh, Daniel and H{\"a}hnel, Martin and Krummenacher, Ivo and Braunschweig, Holger and Finze, Maik and Ji, Lei and Marder, Todd B.},
  title     = {An Iterative Divergent Approach to Conjugated Starburst Borane Dendrimers},
  series = {Chemistry - A European Journal},
  volume    = {26},
  journal   = {Chemistry - A European Journal},
  number    = {57},
  doi       = {10.1002/chem.202001985},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218345},
  pages     = {12951 -- 12963},
  year      = {2020},
  abstract  = {Using a new divergent approach, conjugated triarylborane dendrimers were synthesized up to the 2nd generation. The synthetic strategy consists of three steps: 1) functionalization, via iridium catalyzed C-H borylation; 2) activation, via fluorination of the generated boronate ester with K[HF\(_{2}\)] or [N(nBu\(_{4}\))][HF\(_{2}\)]; and 3) expansion, via reaction of the trifluoroborate salts with aryl Grignard reagents. The concept was also shown to be viable for a convergent approach. All but one of the conjugated borane dendrimers exhibit multiple, distinct and reversible reduction potentials, making them potentially interesting materials for applications in molecular accumulators. Based on their photophysical properties, the 1st generation dendrimers exhibit good conjugation over the whole system. However, the conjugation does not increase further upon expansion to the 2nd generation, but the molar extinction coefficients increase linearly with the number of triarylborane subunits, suggesting a potential application as photonic antennas.},
  language  = {en}
}
@article{NeesKupferHofmannetal.2020,
  author    = {Nees, Samuel and Kupfer, Thomas and Hofmann, Alexander and Braunschweig, Holger},
  title     = {Planar Cyclopenten-4-yl Cations: Highly Delocalized π Aromatics Stabilized by Hyperconjugation},
  series = {Angewandte Chemie International Edition},
  volume    = {59},
  journal   = {Angewandte Chemie International Edition},
  number    = {42},
  doi       = {10.1002/anie.202009644},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218358},
  pages     = {18809 -- 18815},
  year      = {2020},
  abstract  = {Theoretical studies predicted the planar cyclopenten-4-yl cation to be a classical carbocation, and the highest-energy isomer of C\(_{5}\)H\(_{7}\)\(^{+}\). Hence, its existence has not been verified experimentally so far. We were now able to isolate two stable derivatives of the cyclopenten-4-yl cation by reaction of bulky alanes Cp\(^{R}\)AlBr\(_{2}\) with AlBr3. Elucidation of their (electronic) structures by X-ray diffraction and quantum chemistry studies revealed planar geometries and strong hyperconjugation interactions primarily from the C-Al σ bonds to the empty p orbital of the cationic sp\(^{2}\) carbon center. A close inspection of the molecular orbitals (MOs) and of the anisotropy of current (induced) density (ACID), as well as the evaluation of various aromaticity descriptors indicated distinct aromaticity for these cyclopenten-4-yl derivatives, which strongly contrasts the classical description of this system. Here, strong delocalization of π electrons spanning the whole carbocycle has been verified, thus providing rare examples of π aromaticity involving saturated sp\(^{3}\) carbon atoms.},
  language  = {en}
}
@article{SaalfrankFantuzziKupferetal.2020,
  author    = {Saalfrank, Christian and Fantuzzi, Felipe and Kupfer, Thomas and Ritschel, Benedikt and Hammond, Kai and Krummenacher, Ivo and Bertermann, R{\"u}diger and Wirthensohn, Raphael and Finze, Maik and Schmid, Paul and Engel, Volker and Engels, Bernd and Braunschweig, Holger},
  title     = {cAAC-Stabilized 9,10-diboraanthracenes—Acenes with Open-Shell Singlet Biradical Ground States},
  series = {Angewandte Chemie International Edition},
  volume    = {59},
  journal   = {Angewandte Chemie International Edition},
  number    = {43},
  doi       = {10.1002/anie.202008206},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-217795},
  pages     = {19338 -- 19343},
  year      = {2020},
  abstract  = {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.},
  language  = {en}
}
@article{MerzDietzVonhausenetal.2020,
  author    = {Merz, Julia and Dietz, Maximilian and Vonhausen, Yvonne and W{\"o}ber, Frederik and Friedrich, Alexandra and Sieh, Daniel and Krummenacher, Ivo and Braunschweig, Holger and Moos, Michael and Holzapfel, Marco and Lambert, Christoph and Marder, Todd B.},
  title     = {Synthesis, Photophysical and Electronic Properties of New Red-to-NIR Emitting Donor-Acceptor Pyrene Derivatives},
  series = {Chemistry - A European Journal},
  volume    = {26},
  journal   = {Chemistry - A European Journal},
  number    = {2},
  doi       = {10.1002/chem.201904219},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-207486},
  pages     = {438-453},
  year      = {2020},
  abstract  = {We synthesized new pyrene derivatives with strong bis(para -methoxyphenyl)amine donors at the 2,7-positions and n -azaacene acceptors at the K-region of pyrene. The compounds possess a strong intramolecular charge transfer, leading to unusual properties such as emission in the red to NIR region (700 nm), which has not been reported before for monomeric pyrenes. Detailed photophysical studies reveal very long intrinsic lifetimes of >100 ns for the new compounds, which is typical for 2,7-substituted pyrenes but not for K-region substituted pyrenes. The incorporation of strong donors and acceptors leads to very low reduction and oxidation potentials, and spectroelectrochemical studies show that the compounds are on the borderline between localized Robin-Day class-II and delocalized Robin-Day class-III species.},
  language  = {en}
}
@article{HorrerKrahfussLubitzetal.2020,
  author    = {Horrer, G{\"u}nther and Krahfuß, Mirjam J. and Lubitz, Katharina and Krummenacher, Ivo and Braunschweig, Holger and Radius, Udo},
  title     = {N-Heterocyclic Carbene and Cyclic (Alkyl)(amino)carbene Complexes of Titanium(IV) and Titanium(III)},
  series = {European Journal of Inorganic Chemistry},
  volume    = {2020},
  journal   = {European Journal of Inorganic Chemistry},
  number    = {3},
  doi       = {10.1002/ejic.201901207},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-208725},
  pages     = {281-291},
  year      = {2020},
  abstract  = {The reaction of one and two equivalents of the N -heterocyclic carbene IMes [IMes = 1,3-bis(2,4,6-trimethyl-phenyl)imidazolin-2-ylidene] or the cyclic (alkyl)(amino)carbene cAAC\(^{Me}\) [cAAC\(^{Me}\) = 1-(2,6-diisopropyl-phenyl)-3,3,5,5-tetra-methylpyrrolidin-2-ylidene] with [TiCl\(_{4}\)] in n -hexane results in the formation of mono- and bis-carbene complexes [TiCl\(_{4}\)(IMes)] 1 , [TiCl\(_{4}\)(IMes)2] 2 , [TiCl\(_{4}\)(cAAC\(^{Me}\))] 3 , and [TiCl\(_{4}\)(cAAC\(^{Me}\))\(_{2}\)] 4 , respectively. For comparison, the titanium(IV) NHC complex [TiCl\(_{4}\)(Ii Pr\(^{Me}\))] 5 (Ii Pr\(^{Me}\) = 1,3-diisopropyl-4,5-dimethyl-imidazolin-2-ylidene) has been synthesized and structurally characterized. The reaction of [TiCl\(_{4}\)(IMes)] 1 with PMe\(_{3}\) affords the mixed substituted complex [TiCl\(_{4}\)(IMes)(PMe\(_{3}\))] 6 . The reactions of [TiCl\(_{3}\)(THF)\(_{3}\)] with two equivalents of the carbenes IMes and cAAC\(^{Me}\) in n -hexane lead to the clean formation of the titanium(III) complexes [TiCl\(_{3}\)(IMes)\(_{2}\)] 7 and [TiCl\(_{3}\)(cAAC\(^{Me}\))\(_{2}\)] 8 . Compounds 1 -8 have been completely characterized by elemental analysis, IR and multinuclear NMR spectroscopy and for 2 -5 , 7 and 8 by X-ray diffraction. Magnetometry in solution, EPR and UV/Vis spectroscopy and DFT calculations performed on 7 and 8 are indicative of a predominantly metal-centered d\(^{1}\)-radical in both cases.},
  language  = {en}
}
@article{MerzDietrichNitschetal.2020,
  author    = {Merz, Julia and Dietrich, Lena and Nitsch, J{\"o}rn and Krummenacher, Ivo and Braunschweig, Holger and Moos, Michael and Mims, David and Lambert, Christoph and Marder, Todd B.},
  title     = {Synthesis, Photophysical and Electronic Properties of Mono-, Di-, and Tri-Amino-Substituted Ortho-Perylenes, and Comparison to the Tetra-Substituted Derivative},
  series = {Chemistry - A European Journal},
  volume    = {26},
  journal   = {Chemistry - A European Journal},
  number    = {52},
  doi       = {10.1002/chem.202001475},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-217835},
  pages     = {12050 -- 12059},
  year      = {2020},
  abstract  = {We synthesized a series of new mono-, di-, tri- and tetra-substituted perylene derivatives with strong bis(para-methoxyphenyl)amine (DPA) donors at the uncommon 2,5,8,11-positions. The properties of our new donor-substituted perylenes were studied in detail to establish a structure-property relationship. Interesting trends and unusual properties are observed for this series of new perylene derivatives, such as a decreasing charge transfer (CT) character with increasing number of DPA moieties and individual reversible oxidations for each DPA moiety. Thus, (DPA)-Per possesses one reversible oxidation while (DPA)\(_{4}\)-Per has four. The mono- and di-substituted derivatives display unusually large Stokes shifts not previously reported for perylenes. Furthermore, transient absorption measurements of the new derivatives reveal an excited state with lifetimes of several hundred microseconds, which sensitizes singlet oxygen with quantum yields of up to 0.83.},
  language  = {en}
}
@article{BruneckerMuessigArrowsmithetal.2020,
  author    = {Brunecker, Carina and M{\"u}ssig, Jonas H. and Arrowsmith, Merle and Fantuzzi, Felipe and Stoy, Andreas and B{\"o}hnke, Julian and Hofmann, Alexander and Bertermann, R{\"u}diger and Engels, Bernd and Braunschweig, Holger},
  title     = {Boranediyl- and Diborane(4)-1,2-diyl-Bridged Platinum A-Frame Complexes},
  series = {Chemistry - A European Journal},
  volume    = {26},
  journal   = {Chemistry - A European Journal},
  number    = {39},
  doi       = {10.1002/chem.202001168},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-214707},
  pages     = {8518 -- 8523},
  year      = {2020},
  abstract  = {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.},
  language  = {en}
}
@article{MuessigLisinetskayaDewhurstetal.2020,
  author    = {Muessig, Jonas H. and Lisinetskaya, Polina and Dewhurst, Rian D. and Bertermann, R{\"u}diger and Thaler, Melanie and Mitric, Roland and Braunschweig, Holger},
  title     = {Dibortetraiodid (B\(_2\)I\(_4\)) ist im Festk{\"o}rper ein Polymer aus sp3-hybridisiertem Bor},
  series = {Angewandte Chemie},
  volume    = {132},
  journal   = {Angewandte Chemie},
  number    = {14},
  doi       = {10.1002/ange.201913590},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-219653},
  pages     = {5574-5579},
  year      = {2020},
  abstract  = {Anhand der ersten Festk{\"o}rperstrukturen von Dibortetraiodid (B\(_2\)I\(_4\)) wird gezeigt, dass dieses nicht, wie lange angenommen, analog zu den leichteren Dibortetrahalogeniden B\(_2\)F\(_4\), B\(_2\)Cl\(_4\) und B\(_2\)Br\(_4\) in allen Aggregatzust{\"a}nden in Form diskreter Molek{\"u}le mit planaren, dreifach koordinierten Boratomen vorliegt. R{\"o}ntgenstrukturanalysen, Festk{\"o}rper-NMR- und IR-Messungen zeigen, dass B\(_2\)I\(_4\) im Festk{\"o}rper in zwei polymeren Konformeren vorkommt, die tetraedrisch koordinierte Boratome enthalten. Anhand von DFT-Rechnungen werden die IR-Spektren in L{\"o}sung und im Festk{\"o}rper simuliert und mit den experimentellen Daten verglichen.},
  language  = {de}
}
@article{MuessigLisinetskayaDewhurstetal.2020,
  author    = {Muessig, Jonas H. and Lisinetskaya, Polina and Dewhurst, Rian D. and Bertermann, R{\"u}diger and Thaler, Melanie and Mitric, Roland and Braunschweig, Holger},
  title     = {Tetraiododiborane(4) (B\(_2\)I\(_4\)) is a Polymer based on sp\(^3\) Boron in the Solid State},
  series = {Angewandte Chemie International Edition},
  volume    = {59},
  journal   = {Angewandte Chemie International Edition},
  doi       = {10.1002/anie.201913590},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-209428},
  pages     = {5531-5535},
  year      = {2020},
  abstract  = {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.},
  language  = {en}
}
@article{PaprockiHrobarikHarrimanetal.2020,
  author    = {Paprocki, Valerie and Hrob{\´a}rik, Peter and Harriman, Katie L. M. and Luff, Martin S. and Kupfer, Thomas and Kaupp, Martin and Murugesu, Muralee and Braunschweig, Holger},
  title     = {Ein neutrales 1,4-Diborabenzol als \(\pi\)-Ligand in Actinoidkomplexen},
  series = {Angewandte Chemie},
  volume    = {132},
  journal   = {Angewandte Chemie},
  number    = {31},
  doi       = {10.1002/ange.202004501},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218181},
  pages     = {13209 -- 13216},
  year      = {2020},
  abstract  = {Die \(\pi\)-Koordination von Aren- und anionischen Heteroarenliganden ist ein allgegenw{\"a}rtiges Strukturmotiv in der metallorganischen Chemie der d- und f-Block-Elemente. Im Gegensatz dazu sind vergleichbare \(\pi\)-Wechselwirkungen neutraler Heteroarene, darunter auch solche neutraler, aromatischer Borheterocyclen, f{\"u}r den f-Block weit weniger verbreitet, was z. T. mit einer geringeren Effektivit{\"a}t der Metall-zu-Ligand-R{\"u}ckbindung in Zusammenhang gebracht werden kann. F{\"u}r die Actinoide sind π-Komplexe mit neutralen Heteroarenliganden sogar g{\"a}nzlich unbekannt. Durch Ausnutzung der außergew{\"o}hnlichen \(\pi\)-Donorst{\"a}rke eines 1,4-Diborabenzols ist es uns nun gelungen, eine Reihe stabiler π-Halbsandwichkomplexe des Thoriums(IV) und des Urans(IV) {\"u}ber einen erstaunlich einfachen Zugang zu generieren: Umsetzung eines 1,4-Diborabenzols mit ThCl\(_{4}\)(dme)\(_{2}\) bzw. UCl\(_{4}\) in Gegenwart einer Lewis-Base. Hierdurch konnten die ersten Beispiele f{\"u}r Actinoidkomplexe mit einem neutralen Borheterocyclus als Sandwich-artigem Liganden erhalten werden. Laut experimentellen und theoretischen Studien ist die starke Actinoid-Heteroaren-Wechselwirkung in diesen Molek{\"u}len im Wesentlichen von elektrostatischer Natur. Der kovalente Hauptbeitrag wird hingegen von der Ligand-zu-Metall-\(\pi\)-Wechselwirkung geleistet, w{\"a}hrend \(\pi\)/δ-R{\"u}ckbindungsanteile kaum eine Rolle spielen.},
  language  = {de}
}
@article{SaalfrankFantuzziKupferetal.2020,
  author    = {Saalfrank, Christian and Fantuzzi, Felipe and Kupfer, Thomas and Ritschel, Benedikt and Hammond, Kai and Krummenacher, Ivo and Bertermann, R{\"u}diger and Wirthensohn, Raphael and Finze, Maik and Schmid, Paul and Engel, Volker and Engels, Bernd and Braunschweig, Holger},
  title     = {cAAC-stabilisierte 9,10-Diboraanthracene - offenschalige Singulettbiradikale},
  series = {Angewandte Chemie},
  volume    = {132},
  journal   = {Angewandte Chemie},
  number    = {43},
  doi       = {10.1002/ange.202008206},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218582},
  pages     = {19502 -- 19507},
  year      = {2020},
  abstract  = {Geringe HOMO-LUMO-Abst{\"a}nde und eine hohe Ladungstr{\"a}germobilit{\"a}t pr{\"a}destinieren die h{\"o}heren Acene f{\"u}r Anwendungen im Bereich der Organoelektronik. Die Leistungsf{\"a}higkeit derartiger Verbindungen steigt hierbei dramatisch mit der Anzahl anellierter Benzolringe. Gr{\"o}ßere Acenmengen sind synthetisch bisher jedoch nur f{\"u}r Acene bis Heptacen verl{\"a}sslich zug{\"a}nglich. Theoretischen Studien zufolge besitzen (Oligo)acene offenschalige Singulettbiradikal- und (Poly)acene polyradikalische Grundzust{\"a}nde. Eindeutige experimentelle Belege f{\"u}r diese Vorhersagen sind hingegen {\"a}ußerst selten. Durch den Einbau von zwei Boratomen in das Anthracengrundger{\"u}st konnten wir den HOMO-LUMO-Abstand von Acenen dramatisch verringern und zwar ohne die Notwendigkeit einer Ausweitung des konjugierten π-Systems. Stabilisierung der Borzentren durch cyclische (Alkyl)(amino)carbene lieferte hierbei neutrale 9,10-Diboraanthracene mit disjunkten, offenschaligen Singulettbiradikal-Grundzust{\"a}nden.},
  language  = {en}
}
@article{GerlachMonningerSchleieretal.2021,
  author    = {Gerlach, Marius and Monninger, Sophie and Schleier, Domenik and Hemberger, Patrick and Goettel, James T. and Braunschweig, Holger and Fischer, Ingo},
  title     = {Photoelectron Photoion Coincidence Spectroscopy of NCl\(_{3}\) and NCl\(_{2}\)},
  series = {ChemPhysChem},
  volume    = {22},
  journal   = {ChemPhysChem},
  number    = {21},
  doi       = {10.1002/cphc.202100537},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257322},
  pages     = {2164-2167},
  year      = {2021},
  abstract  = {We investigate NCl\(_{3}\) and the NCl\(_{2}\) radical by photoelectron-photoion coincidence spectroscopy using synchrotron radiation. The mass selected threshold photoelectron spectrum (ms-TPES) of NCl\(_{3}\) is broad and unstructured due to the large geometry change. An ionization energy of 9.7±0.1 eV is estimated from the spectrum and supported by computations. NCl2 is generated by photolysis at 213 nm from NCl\(_{3}\) and its ms-TPES shows an extended vibrational progression with a 90 meV spacing that is assigned to the symmetric N-Cl stretching mode in the cation. An adiabatic ionization energy of 9.94 ± 0.02 eV is determined.},
  language  = {en}
}
@article{RamlerFantuzziGeistetal.2021,
  author    = {Ramler, Jaqueline and Fantuzzi, Felipe and Geist, Felix and Hanft, Anna and Braunschweig, Holger and Engels, Bernd and Lichtenberg, Crispin},
  title     = {The dimethylbismuth cation: entry into dative Bi-Bi bonding and unconventional methyl exchange},
  series = {Angewandte Chemie International Edition},
  volume    = {60},
  journal   = {Angewandte Chemie International Edition},
  doi       = {10.1002/anie.202109545},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256543},
  pages     = {24388-24394},
  year      = {2021},
  abstract  = {The dimethyl bismuth cation, [BiMe\(_2\)(SbF\(_6\))], has been isolated and characterized. Reaction with BiMe\(_3\) allows access to the first compound featuring Bi→Bi donor-acceptor bonding. In solution, dynamic behavior with methyl exchange via an unusual S\(_E\)2 mechanism is observed, underlining the unique properties of bismuth species as soft Lewis acids with the ability to undergo reversible Bi-C bond cleavage.},
  language  = {en}
}
@article{SchorrSchopperRienschetal.2021,
  author    = {Schorr, Fabian and Schopper, Nils and Riensch, Nicolas and Fantuzzi, Felipe and Neder, Marco and Dewhurst, Rian D. and Thiess, Thorsten and Br{\"u}ckner, Tobias and Hammond, Kai and Helten, Holger and Finze, Maik and Braunschweig, Holger},
  title     = {Controlled Synthesis of Oligomers Containing Main-Chain B(sp\(^{2}\))-B(sp\(^{2}\)) Bonds},
  series = {Chemistry—A European Journal},
  volume    = {27},
  journal   = {Chemistry—A European Journal},
  number    = {64},
  doi       = {10.1002/chem.202103366},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257274},
  pages     = {16043-16048},
  year      = {2021},
  abstract  = {A number of novel alkynyl-functionalized diarylbis(dimethylamino)diboranes(4) are prepared by salt metathesis, and the appended alkynyl groups are subjected to hydroboration. Their reactions with monohydroboranes lead to discrete boryl-appended diborane(4) species, while dihydroboranes induce their catenation to oligomeric species, the first known examples of well-characterized macromolecular species with B-B bonds. The oligomeric species were found to comprise up to ten repeat units and are soluble in common organic solvents. Some of the oligomeric species have good air stability and all were characterized by NMR and vibrational spectroscopy and size-exclusion chromatography techniques.},
  language  = {en}
}
@article{BergerRueheSchwarzmannetal.2021,
  author    = {Berger, Sarina M. and R{\"u}he, Jessica and Schwarzmann, Johannes and Phillipps, Alexandra and Richard, Ann-Katrin and Ferger, Matthias and Krummenacher, Ivo and Tumir, Lidija-Marija and Ban, Željka and Crnolatac, Ivo and Majhen, Dragomira and Barišić, Ivan and Piantanida, Ivo and Schleier, Domenik and Griesbeck, Stefanie and Friedrich, Alexandra and Braunschweig, Holger and Marder, Todd B.},
  title     = {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},
  series = {Chemistry—A European Journal},
  volume    = {27},
  journal   = {Chemistry—A European Journal},
  number    = {56},
  doi       = {10.1002/chem.202102308},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256963},
  pages     = {14057-14072},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}
@article{LindlGuoKrummenacheretal.2021,
  author    = {Lindl, Felix and Guo, Xueying and Krummenacher, Ivo and Rauch, Florian and Rempel, Anna and Paprocki, Valerie and Dellermann, Theresa and Stennett, Tom E. and Lamprecht, Anna and Br{\"u}ckner, Tobias and Radacki, Krzysztof and B{\´e}langer-Chabot, Guillaume and Marder, Todd B. and Lin, Zhenyang and Braunschweig, Holger},
  title     = {Rethinking Borole Cycloaddition Reactivity},
  series = {Chemistry—A European Journal},
  volume    = {27},
  journal   = {Chemistry—A European Journal},
  number    = {43},
  doi       = {10.1002/chem.202101290},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256888},
  pages     = {11226-11233},
  year      = {2021},
  abstract  = {Boroles are attracting broad interest for their myriad and diverse applications, including in synthesis, small molecule activation and functional materials. Their properties and reactivity are closely linked to the cyclic conjugated diene system, which has been shown to participate in cycloaddition reactions, such as the Diels-Alder reaction with alkynes. The reaction steps leading to boranorbornadienes, borepins and tricyclic boracyclohexenes from the thermal reaction of boroles with alkynes are seemingly well understood as judged from the literature. Herein, we question the long-established mechanistic picture of pericyclic rearrangements by demonstrating that seven-membered borepins (i. e., heptaphenylborepin and two derivatives substituted with a thienyl and chloride substituent on boron) exist in a dynamic equilibrium with the corresponding bicyclic boranorbornadienes, the direct Diels-Alder products, but are not isolable products from the reactions. Heating gradually converts the isomeric mixtures into fluorescent tricyclic boracyclohexenes, the most stable isomers in the series. Results from mechanistic DFT calculations reveal that the tricyclic compounds derive from the boranorbornadienes and not the borepins, which were previously believed to be intermediates in purely pericyclic processes.},
  language  = {en}
}