Silver(I) N-heterocyclic carbene halide complexes: A new bonding motif

Two new NHC silver halide salts have been synthesised and structurally characterised, and they show the two most common structural forms for such salts: the (NHC)AgX and the forms (both have a stoichiometry of 1 NHC:1 Ag:1 halide). A third new compound has been synthesised and structurally characterised: this compound has an unprecedented 2 NHC:1 Ag:1 halide stoichiometry and exhibits a planar arrangement of two coordinating NHCs, and a coordinating bromide about the central silver. The Ag–Br bond is long in the solid state and, together with solution NMR data, this suggests that a formulation of (NHC)2Ag+Br− might be more appropriate