Four boron atoms, four positive charges, and four skeletal electrons

• Verfasst von: Widera, Anna [VerfasserIn]
• Verfasst von: Wadepohl, Hubert [VerfasserIn]
• Verfasst von: Himmel, Hans-Jörg [VerfasserIn]
• Titel: Four boron atoms, four positive charges, and four skeletal electrons
• Titelzusatz: a fluorescent [sigma]-aromatic tetraborane(4)
• Verf.angabe: Anna Widera, Hubert Wadepohl, and Hans-Jörg Himmel
• E-Jahr: 2019
• Jahr: 14 January 2019
• Umfang: 5 S.
• Fussnoten: Im Titel ist "Sigma" als griechischer Buchstaben dargestellt ; Gesehen am 23.10.2019
• Titel Quelle: Enthalten in: Angewandte Chemie / International edition
• Ort Quelle: Weinheim : Wiley-VCH, 1962
• Jahr Quelle: 2019
• Band/Heft Quelle: 58(2019), 18, Seite 5897-5901
• ISSN Quelle: 1521-3773
• DOI: doi:10.1002/anie.201814041
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: boron
• Sach-SW: fluorescence
• Sach-SW: lattice energy
• Sach-SW: multicenter bonds
• Sach-SW: σ-aromaticity
• K10plus-PPN: 1679476750

Abstract

Reaction of a ditriflatodiborane compound with the Lewis acids AlCl3 or GaCl3 leads to abstraction of the two triflate substituents and dimerization of the resulting dicationic diborane to give a σ-aromatic tetracationic tetraborane with a planar, rhomboid B4 core. The compound exhibits four skeletal σ-electrons involved in two (3c,2e) bonds and represents the first stable fourfold base-stabilized [B4H4]4+ analogue. The product is isolated from the reaction mixture in the form of bright orange crystals that display fluorescence. Further analysis shows that the new tetraborane(4) is stabilized in the solid state by the lattice energy. It exhibits an extremely high electron affinity and is only stable in solution after one-electron reduction to the radical cation.