title: Reversible Dihydrogen Activation by Reduced Aryl Boranes as Main-Group Ambiphiles.
abstract: A new approach to main-group H2activation combining concepts of transition-metal and frustrated Lewis pair chemistry is reported. Ambiphilic, metal-like reactivity toward H2can be conferred to 9,10-dihydro-9,10-diboraanthracene (DBA) acceptors by the injection of two electrons. The resulting [DBA]2-ions cleave the H-H bond with the formation of hydridoborates under moderate conditions (T=50-100 °C; p<1 atm). Depending on the boron-bonded substituents R, the addition is either reversible (R=C≡CtBu) or irreversible (R=H). The reaction rate is strongly influenced by the nature and the coordination behavior of the countercation (Li+slower than K+). Quantum-chemical calculations support the experimental observations and suggest a concerted, homolytic addition of H2across both boron atoms. As proven by the successful conversion of Me3SiCl into Me3SiH, the system Li2[DBA]/H2appears generally relevant for the hydrogenation of element-halide bonds.
authors.affiliation: Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt (Main), Germany.
authors.forename: Esther
authors.initials: E
authors.lastname: von Grotthuss
authors.affiliation: Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt (Main), Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Diefenbach
authors.affiliation: Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt (Main), Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Bolte
authors.affiliation: Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt (Main), Germany.
authors.forename: Hans-Wolfram
authors.initials: HW
authors.lastname: Lerner
authors.affiliation: Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt (Main), Germany. Max.Holthausen@chemie.uni-frankfurt.de.
authors.forename: Max C
authors.initials: MC
authors.lastname: Holthausen
authors.affiliation: Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt (Main), Germany. Matthias.Wagner@chemie.uni-frankfurt.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Wagner
keywords: H2 activation; boron; main-group ambiphiles; quantum-chemical calculations; reduction