Approaching monocoordination at a silver(I) cation

The recently reported bulky N-heterocyclic carbene ITr (ITr = [(HCNCPh₃)₂C:]) was found to stabilize low-coordinate Ag(I) environments. These electrophilic species were crystallographically identified as the weak solvates [(ITr)Ag(sol)]⁺ (sol = PhF, MesH or CH₂Cl₂) and as a solvent-free dimer [(ITr)Ag]₂²⁺. The highly electrophilic nature of the [(ITr)Ag]⁺ cation was further demonstrated by the calculation of a very high methyl ion affinity (MIA) and the synthesis of [(ITr)Ag(PCO)] which features substantial side-on electron donation from a P–C π bond to Ag.