N-heterocyclic carbene coinage metal complexes as intense blue-green emitters

The reaction of N-methyl (Me) or N-benzyl (Bn) imidazole with 9-chloroacridine (9-ClAcr) gives the corresponding imidazolium salts, [(RimAcr)H]Cl (R = Me, Bn), which can further react with AgBF 4 or [Au(C 6F 5)(tht)], affording the new salts [(RimAcr)H]BF 4 or [(RimAcr)H][Au(C 6F 5)Cl]. Silver(I) carbene complexes of the form [AgCl(RimAcr)] or [Ag(RimAcr) 2]BF 4 are synthesized by reaction of the corresponding imidazolium salts with Ag 2O or Ag 2O and NaOH. Transmetalation reactions allow the synthesis of the gold and copper derivatives [MCl(RimAcr)] (M = Au, Cu) and [Au(RimAcr) 2]BF 4. Treatment of [(RimAcr)H][Au(C 6F 5)Cl] with NaH affords the synthesis of the carbene complexes [Au(C 6F 5)(RimAcr)]. The crystal structures of these complexes show interesting π·· ·π stacking interactions between the acridine and/or the pentafluorophenyl groups. The imidazolium salts and the gold and silver complexes are intense blue-green emitters. © 2012 American Chemical Society.Authors thank the Ministerio de Economía y Competitividad (MEC/FEDER CTQ2010-20500-C02-01) for financial support.Peer Reviewe