title: Generation of Dicoordinate Boron(I) Units by Fragmentation of a Tetra-Boron(I) Molecular Square.
abstract: Reduction of carbene-borane adduct [(cAAC)BBr2(CN)] (cAAC=1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) cleanly yielded the tetra(cyanoborylene) species [(cAAC)B(CN)]4presenting a 12-membered (BCN)4ring. The analysis of the Kohn-Sham molecular orbitals showed significant borylene character of the BIatoms. [(cAAC)B(CN)]4was found to reduce two equivalents of AgCN per boron center to yield [(cAAC)B(CN)3] and fragmented into two-coordinate boron(I) units upon reaction with IMeMe (1,3,4,5-tetramethylimidazol-2-ylidene) to yield the corresponding tricoordinate mixed cAAC-NHC cyanoborylene. The analogous cAAC-phosphine cyanoborylene was obtained by reduction of [(cAAC)BBr2(CN)] in the presence of excess phosphine.
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.|Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Merle
authors.initials: M
authors.lastname: Arrowsmith
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.|Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Dominic
authors.initials: D
authors.lastname: Auerhammer
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.|Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Bertermann
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany. h.braunschweig@uni-wuerzburg.de.|Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany. h.braunschweig@uni-wuerzburg.de.
authors.forename: Holger
authors.initials: H
authors.lastname: Braunschweig
authors.affiliation: Institut für Organische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Bringmann
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.|Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Mehmet Ali
authors.initials: MA
authors.lastname: Celik
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.|Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Rian D
authors.initials: RD
authors.lastname: Dewhurst
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.|Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Maik
authors.initials: M
authors.lastname: Finze
authors.affiliation: Institut für Organische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Grüne
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.|Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Hailmann
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.|Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hertle
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.|Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Ivo
authors.initials: I
authors.lastname: Krummenacher
keywords: bonding; borylene; cyclic (alkyl)(amino)carbenes; low-valent compounds; reduction