A chemiluminescent tetraaryl diborane(4) tetraanion

  • Two subvalent, redox-active diborane(4) anions, [3]4− and [3]2−, carrying exceptionally high negative charge densities are reported: Reduction of 9-methoxy-9-borafluorene with Li granules without stirring leads to the crystallization of the B(sp3)−B(sp2) diborane(5) anion salt Li[5]. [5]− contains a 2,2′-biphenyldiyl-bridged B−B core, a chelating 2,2′-biphenyldiyl moiety, and a MeO substituent. Reduction of Li[5] with Na metal gives the Na+ salt of the tetraanion [3]4− in which two doubly reduced 9-borafluorenyl fragments are linked via a B−B single bond. Comproportionation of Li[5] and Na4[3] quantitatively furnishes the diborane(4) dianion salt Na2[3], the doubly boron-doped congener of 9,9′-bis(fluorenylidene). Under acid catalysis, Na2[3] undergoes a formal Stone–Wales rearrangement to yield a dibenzo[g,p]chrysene derivative with B=B core. Na2[3] shows boron-centered nucleophilicity toward n-butyl chloride. Na4[3] produces bright blue chemiluminescence when exposed to air.
Author:Hendrik Budy, Thomas Kaese, Michael BolteORCiD, Hans-Wolfram LernerGND, Matthias Wagner
Parent Title (German):Angewandte Chemie
Place of publication:Weinheim
Document Type:Article
Date of Publication (online):2021/06/23
Date of first Publication:2021/06/23
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2022/04/05
Tag:9-borafluorene; boryl anions; chemiluminescence; redox chemistry; subvalent compounds
Page Number:9
First Page:19397
Last Page:19405
Open access funding enabled and organized by Projekt DEAL.
Institutes:Biochemie, Chemie und Pharmazie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Licence (German):License LogoCreative Commons - Namensnennung-Nicht kommerziell - Keine Bearbeitung 4.0