| Abstract: | Isolation of E-1,2-bis(4-bromophenyl)-1,2-diphenyl-ethylene from the E/Z isomer mixture obtained by a Mc Murry coupling reaction and reaction of this isomer with imidazole followed by N-alkylation with n Bu Br and anion exchange yielded the bisimidazolium tetraphenylethylene (TPE) derivative H_2-E-1(PF_6)_2.The reaction of H_2-E-1(PF_6)_2 with Ag_2O yielded the dinuclear metallarectangleAg_2(E-1)_2](PF_6)_2 where the two bis-NHC donors E-1 bridge two silver atoms.Irradiation ofAg_2(E-1)_2](PF_6)_2 leads to E/Z isomerization of the di-NHC ligand and formation of Z-1 in the mononuclear complexAg(Z-1)]PF_6.Demetallation of the di-NHC ligand with NH_4Cl/NH_4PF_6 yielded bisimidazolium salt H_2-Z-1(PF_6)_2.The unique isomerization of the E-TPE derivative into its Z-isomer via metal complex formation/irradiation/demetallation cannot be achieved by irradiation of the individual imidazolium salt.The emissive properties of the TPE complexesAg_2(E-1)_2](PF_6)_2 andAg(Z-1)]PF_6 have been investigated. |
