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Updated: Jan 22, 2026

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
Published on: July 30, 2017
Gold(I) Complexes Stabilized by Nine- and Ten-Membered N-Heterocyclic Carbene Ligands
Alejandro Cervantes-Reyes1, Frank Rominger1, Matthias Rudolph1
1Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
Abstract:
Nine- and ten-membered N-heterocyclic carbene (NHC) ligands have been developed and for the first time their gold(I) complexes were synthesized. The protonated NHC pro-ligands 2 a-h were prepared by the reaction of readily available N,N'-diarylformamidines with bis-electrophilic building blocks, followed by anion exchange. In situ deprotonation of the tetrafluoroborates 2 a-h with tBuOK in the presence of AuCl(SMe2 ) provided fast access to NHC-gold(I) complexes 3-10. These new NHC-gold(I) complexes show very good catalytic activity in a cycloisomerization reaction (0.1 mol % catalyst loading, up to 100 % conversion) and their solid-state structures reveal high steric hindrance around the metal atom (%Vbur up to 53.0) which is caused by their expanded-ring architecture.
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