The Striking Stabilization of Ni 0 (η 6 ‐Arene) Complexes by an Ylide‐Like Silylene Ligand

The right mix does the trick : Elusive {Ni 0 (η 6 ‐arene)} moieties can be dramatically stabilized by the N‐heterocyclic silylene ligand 1 , which has a zwitterionic mesomeric structure. The σ, π‐acid–base synergism between nickel and 1 explains the unexpectedly high stability of the new silylene complexes 2 , which enables arene exchange studies at a Ni 0 center. Addition of B(C 6 F 5 ) 3 to 2 affords the zwitterionic silylene complex 3 (see scheme, R=2,6‐ i Pr 2 C 6 H 3 ).