Cover Picture: Heterolytic Dihydrogen Activation by a Frustrated Carbene–Borane Lewis Pair / Hydrogen and Amine Activation by a Frustrated Lewis Pair of a Bulky N‐Heterocyclic Carbene and B(C6F5)3 (Angew. Chem. Int. Ed. 39/2008)

Abstract

Forcing a square peg into a round hole: tBu2ImC: and B(C6F5)3 form a frustrated Lewis pair (FLP), allowing the synergistic activation of H2. On page 7428 ff., M. Tamm et al. describe how the irreversible formation of an abnormal carbene–borane adduct eliminates mismatching between acid and base so that this system can circumvent frustration at the expense of activity. In addition, D. W. Stephan and P. A. Chase demonstrate on page 7433 ff. that this FLP combination not only effects heterolytic cleavage of H2, but also of amine NH bonds.