@article{WeiserCuiDewhurstetal.2023,
  author    = {Weiser, Jonas and Cui, Jingjing and Dewhurst, Rian D. and Braunschweig, Holger and Engels, Bernd and Fantuzzi, Felipe},
  title     = {Structure and bonding of proximity-enforced main-group dimers stabilized by a rigid naphthyridine diimine ligand},
  series = {Journal of Computational Chemistry},
  volume    = {44},
  journal   = {Journal of Computational Chemistry},
  number    = {3},
  doi       = {10.1002/jcc.26994},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312586},
  pages     = {456 -- 467},
  year      = {2023},
  abstract  = {The development of ligands capable of effectively stabilizing highly reactive main-group species has led to the experimental realization of a variety of systems with fascinating properties. In this work, we computationally investigate the electronic, structural, energetic, and bonding features of proximity-enforced group 13-15 homodimers stabilized by a rigid expanded pincer ligand based on the 1,8-naphthyridine (napy) core. We show that the redox-active naphthyridine diimine (NDI) ligand enables a wide variety of structural motifs and element-element interaction modes, the latter ranging from isolated, element-centered lone pairs (e.g., E = Si, Ge) to cases where through-space π bonds (E = Pb), element-element multiple bonds (E = P, As) and biradical ground states (E = N) are observed. Our results hint at the feasibility of NDI-E2 species as viable synthetic targets, highlighting the versatility and potential applications of napy-based ligands in main-group chemistry.},
  language  = {en}
}
@article{BruecknerRitschelJimenez‐Hallaetal.2023,
  author    = {Br{\"u}ckner, Tobias and Ritschel, Benedikt and Jim{\´e}nez-Halla, J. Oscar C. and Fantuzzi, Felipe and Duwe, Dario and Markl, Christian and Dewhurst, Rian D. and Dietz, Maximilian and Braunschweig, Holger},
  title     = {Metal-Free Intermolecular C-H Borylation of N-Heterocycles at B-B Multiple Bonds},
  series = {Angewandte Chemie International Edition},
  volume    = {62},
  journal   = {Angewandte Chemie International Edition},
  number    = {5},
  doi       = {10.1002/anie.202213284},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312385},
  year      = {2023},
  abstract  = {Carbene-stabilized diborynes of the form LBBL (L=N-heterocyclic carbene (NHC) or cyclic alkyl(amino)carbene (CAAC)) induce rapid, high yielding, intermolecular ortho-C-H borylation at N-heterocycles at room temperature. A simple pyridyldiborene is formed when an NHC-stabilized diboryne is combined with pyridine, while a CAAC-stabilized diboryne leads to activation of two pyridine molecules to give a tricyclic alkylideneborane, which can be forced to undergo a further H-shift resulting in a zwitterionic, doubly benzo-fused 1,3,2,5-diazadiborinine by heating. Use of the extended N-heteroaromatic quinoline leads to a borylmethyleneborane under mild conditions via an unprecedented boron-carbon exchange process.},
  language  = {en}
}
@article{WitteArrowsmithLamprechtetal.2023,
  author    = {Witte, Robert and Arrowsmith, Merle and Lamprecht, Anna and Schorr, Fabian and Krummenacher, Ivo and Braunschweig, Holger},
  title     = {C-C and C-N Bond Activation, Lewis-Base Coordination and One- and Two-Electron Oxidation at a Linear Aminoborylene},
  series = {Chemistry - A European Journal},
  volume    = {29},
  journal   = {Chemistry - A European Journal},
  number    = {16},
  doi       = {10.1002/chem.202203663},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312491},
  year      = {2023},
  abstract  = {A cyclic alkyl(amino)carbene (CAAC)-stabilized dicoordinate aminoborylene is synthesized by the twofold reduction of a [(CAAC)BCl\(_{2}\)(TMP)] (TMP=2,6-tetramethylpiperidyl) precursor. NMR-spectroscopic, X-ray crystallographic and computational analyses confirm the cumulenic nature of the central C=B=N moiety. Irradiation of [(CAAC)B(TMP)] (2) resulted in an intramolecular C-C bond activation, leading to a doubly-fused C\(_{10}\)BN heterocycle, while the reaction with acetonitrile resulted in an aryl migration from the CAAC to the acetonitrile nitrogen atom, concomitant with tautomerization of the latter to a boron-bound allylamino ligand. One-electron oxidation of 2 with CuX (X=Cl, Br) afforded the corresponding amino(halo)boryl radicals, which were characterized by EPR spectroscopy and DFT calculations. Placing 2 under an atmosphere of CO afforded the tricoordinate (CAAC,CO)-stabilized aminoborylene. Finally, the twofold oxidation of 2 with chalcogens led, in the case of N\(_{2}\)O and sulfur, to the splitting of the B-C\(_{CAAC}\) bond and formation of the 2,4-diamino-1,3,2,4-dichalcogenadiboretanes and CAAC-chalcogen adducts, whereas with selenium a monomeric boraselenone was isolated, which showed some degree of B-Se multiple bonding.},
  language  = {en}
}
@article{LindlLamprechtArrowsmithetal.2023,
  author    = {Lindl, Felix and Lamprecht, Anna and Arrowsmith, Merle and Khitro, Eugen and Rempel, Anna and Dietz, Maximilian and Wellnitz, Tim and B{\´e}langer-Chabot, Guillaume and Stoy, Andreas and Paprocki, Valerie and Prieschl, Dominik and Lenczyk, Carsten and Ramler, Jacqueline and Lichtenberg, Crispin and Braunschweig, Holger},
  title     = {Aromatic 1,2-Azaborinin-1-yls as Electron-Withdrawing Anionic Nitrogen Ligands for Main Group Elements},
  series = {Chemistry - A European Journal},
  volume    = {29},
  journal   = {Chemistry - A European Journal},
  number    = {11},
  doi       = {10.1002/chem.202203345},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312222},
  year      = {2023},
  abstract  = {The 2-aryl-3,4,5,6-tetraphenyl-1,2-azaborinines 1-EMe\(_{3}\) and 2-EMe\(_{3}\) (E=Si, Sn; aryl=Ph (1), Mes (=2,4,6-trimethylphenyl, 2)) were synthesized by ring-expansion of borole precursors with N\(_{3}\)EMe\(_{3}\)-derived nitrenes. Desilylative hydrolysis of 1- and 2-SiMe\(_{3}\) yielded the corresponding N-protonated azaborinines, which were deprotonated with nBuLi or MN(SiMe\(_{3}\))\(_{2}\) (M=Na, K) to the corresponding group 1 salts, 1-M and 2-M. While the lithium salts crystallized as monomeric Lewis base adducts, the potassium salts formed coordination polymers or oligomers via intramolecular K⋅⋅⋅aryl π interactions. The reaction of 1-M or 2-M with CO\(_{2}\) yielded N-carboxylate salts, which were derivatized by salt metathesis to methyl and silyl esters. Salt metathesis of 1-M or 2-M with methyl triflate, [Cp*BeCl] (Cp*=C\(_{5}\)Me\(_{5}\)), BBr\(_{2}\)Ar (Ar=Ph, Mes, 2-thienyl), ECl\(_{3}\) (E=B, Al, Ga) and PX\(_{3}\) (X=Cl, Br) afforded the respective group 2, 13 and 15 1,2-azaborinin-2-yl complexes. Salt metathesis of 1-K with BBr\(_{3}\) resulted not only in N-borylation but also Ph-Br exchange between the endocyclic and exocyclic boron atoms. Solution \(^{11}\)B NMR data suggest that the 1,2-azaborinin-2-yl ligand is similarly electron-withdrawing to a bromide. In the solid state the endocyclic bond length alternation and the twisting of the C\(_{4}\)BN ring increase with the sterics of the substituents at the boron and nitrogen atoms, respectively. Regression analyses revealed that the downfield shift of the endocyclic \(^{11}\)B NMR resonances is linearly correlated to both the degree of twisting of the C\(_{4}\)BN ring and the tilt angle of the N-substituent. Calculations indicate that the 1,2-azaborinin-1-yl ligand has no sizeable π-donor ability and that the aromaticity of the ring can be subtly tuned by the electronics of the N-substituent.},
  language  = {en}
}
@article{HaerterichMatlerDewhurstetal.2023,
  author    = {H{\"a}rterich, Marcel and Matler, Alexander and Dewhurst, Rian D. and Sachs, Andreas and Oppel, Kai and Stoy, Andreas and Braunschweig, Holger},
  title     = {A step-for-step main-group replica of the Fischer carbene synthesis at a borylene carbonyl},
  series = {Nature Communications},
  volume    = {14},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-023-36251-3},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357270},
  year      = {2023},
  abstract  = {The Fischer carbene synthesis, involving the conversion of a transition metal (TM)-bound CO ligand to a carbene ligand of the form [=C(OR')R] (R, R' = organyl groups), is one of the seminal reactions in the history of organometallic chemistry. Carbonyl complexes of p-block elements, of the form [E(CO)n] (E = main-group fragment), are much less abundant than their TM cousins; this scarcity and the general instability of low-valent p-block species means that replicating the historical reactions of TM carbonyls is often very difficult. Here we present a step-for-step replica of the Fischer carbene synthesis at a borylene carbonyl involving nucleophilic attack at the carbonyl carbon followed by electrophilic quenching at the resultant acylate oxygen atom. These reactions provide borylene acylates and alkoxy-/silyloxy-substituted alkylideneboranes, main-group analogues of the archetypal transition metal acylate and Fischer carbene families, respectively. When either the incoming electrophile or the boron center has a modest steric profile, the electrophile instead attacks at the boron atom, leading to carbene-stabilized acylboranes - boron analogues of the well-known transition metal acyl complexes. These results constitute faithful main-group replicas of a number of historical organometallic processes and pave the way to further advances in the field of main-group metallomimetics.},
  language  = {en}
}