Erzeugung zweifach koordinierter Bor(I)‐Einheiten durch Fragmentierung eines molekularen Tetra‐Bor(I)‐Quadrats

Abstract

Die Reduktion des Carbenboranaddukts [(cAAC)BBr 2 (CN)] (cAAC = 1-(2,6-Diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-yliden) verlief sauber zur Tetra(cyanoborylen)verbindung [(cAAC)B(CN)] 4 ,w elche einen zwçlfgliedrigen (BCN) 4 -Ring aufweist. Die Analyse der Kohn-Sham-Molekülorbitale zeigte eindeutige Boryleneigenschaften der B I -Atome.E inerseits reduzierte [(cAAC)B(CN)] 4 zwei ¾quivalente AgCN unter Bildung von [(cAAC)B(CN) 3 ], andererseits fragmentierte es in der Reaktion mit IMeMe (1,3,4,5-Tetramethylimidazol-2-yliden) zu divalenten Bor(I)-Einheiten und ergab dabei das entsprechende dreifach koordinierte,g emischte cAAC-NHC-Cyanoborylen. Das analoge cAAC-Phosphan-Cyanoborylen wurde durch die Reduktion von [(cAAC)BBr 2 (CN)] in Gegenwart eines Überschusses an Phosphan erhalten.

The Lightest Element Phosphoranylidene: NHC‐Supported Cyclic Borylidene–Phosphorane with Significant B=P Character

“…Particularly,t he nitrogen analogues, phosphazenes II,have attracted significant attention owing to the wide variety of applications as precursors of fireproof polymers [2] and as non-nucleophilic strong bases. [11] Among these,w eh ave been interested in the lightest homologue in the series,t he boron-centered phosphonium ylide V.P hosphorus bora-ylide V can also be regarded as aborylene stabilized by aphosphine ligand. [5] Several stable phosphanylidene-phosphoranes IV [6][7][8] have also been used as phosphinidene transfer agents.B oth the strong s-a nd p-donor character of IV make them excellent ligands for transition metals [9] and for the stabilization of low-valent highly reactive species.…”

“…[3,4] In contrast, the heavier analogues of I,s ila-ylides III,p resent an enhanced silylenoide character with at ransition-metal-like behavior owing to the weak SiÀPinteraction without any SiÀP p-bond character. [11] Among these,w eh ave been interested in the lightest homologue in the series,t he boron-centered phosphonium ylide V.P hosphorus bora-ylide V can also be regarded as aborylene stabilized by aphosphine ligand. [10] Despite numerous examples of phosphonium ylides with Group-14-16 elements,t he synthesis of Group 13 elementbased stable phosphorus ylides is still extremely rare.…”

“…[5] Several stable phosphanylidene-phosphoranes IV [6][7][8] have also been used as phosphinidene transfer agents.B oth the strong s-a nd p-donor character of IV make them excellent ligands for transition metals [9] and for the stabilization of low-valent highly reactive species. [11] Among these,w eh ave been interested in the lightest homologue in the series,t he boron-centered phosphonium ylide V.P hosphorus bora-ylide V can also be regarded as aborylene stabilized by aphosphine ligand. [11] Among these,w eh ave been interested in the lightest homologue in the series,t he boron-centered phosphonium ylide V.P hosphorus bora-ylide V can also be regarded as aborylene stabilized by aphosphine ligand.…”

Exceptionally Strong Electron‐Donating Ability of Bora‐Ylide Substituent vis‐à‐vis Silylene and Silylium Ion

“…[12] Since the first isolation of ab orylene stabilized by two cyclic alkyl-amino carbenes (cAAC) VII by Bertrand et al, [13] several stable borylene complexes with different ligands have been described VIII, IX. [16,17] Of particular interest, these boron species,b eing isoelectronic with amines,p resent an ucleophilic three-coordinate boron center with al one-pair, [13,14] and it has been clearly demonstrated that they can be used as s-donating ligands for transition metals. [16,17] Of particular interest, these boron species,b eing isoelectronic with amines,p resent an ucleophilic three-coordinate boron center with al one-pair, [13,14] and it has been clearly demonstrated that they can be used as s-donating ligands for transition metals.…”

New Members of the Editorial Board and International Advisory Board

“…[1] Braunschweig gehçrt ab 2017 außerdem dem International Advisory Board des European Journal of Inorganic Chemistry an. 1991-1992 war er Postdoc bei Michael F. Lappert an der University of Sussex;d anach kehrte er nach Aachen zurück, um sich bei Paetzold zu habilitieren;1998 wurde er in Aachen Dozent.…”