Reversible Dihydrogen Activation by Reduced Aryl Boranes as Main‐Group Ambiphiles |
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| Authors: | M Sc Esther von Grotthuss Dr Martin Diefenbach Dr Michael Bolte Dr Hans‐Wolfram Lerner Prof Dr Max C Holthausen Prof Dr Matthias Wagner |
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| Affiliation: | Institut für Anorganische Chemie, Goethe-Universit?t Frankfurt, Frankfurt (Main), Germany |
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| Abstract: | A new approach to main‐group H2 activation combining concepts of transition‐metal and frustrated Lewis pair chemistry is reported. Ambiphilic, metal‐like reactivity toward H2 can 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 H2 across both boron atoms. As proven by the successful conversion of Me3SiCl into Me3SiH, the system Li2DBA]/H2 appears generally relevant for the hydrogenation of element–halide bonds. |
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| Keywords: | boron H2 activation main-group ambiphiles quantum-chemical calculations reduction |
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