Phosphorescent monometallic and bimetallic two-coordinate Au(I) complexes with N–heterocyclic carbene and aryl ligands

Abstract A series of mononuclear and binuclear two coordinate Au(I) complexes consisting of a MAC carbene ligand (1,3-bis(2,6-diisopropylphenyl)-5,5-dimethyl-4-keto-tetrahydropyridylidene) and an aryl ligand, including phenyl, biphenyl, naphthyl and anthryl, are reported. The oxidation potential is controlled by the choice of arene ligand, whereas the reduction potential of the complexes is determined by their common MAC carbene ligand. Owing to the heavy atom effect of Au and the aryl ligand–based T1 state, most of these complexes present phosphorescent emission in both solution and polymer film. A high photoluminescence efficiency (ΦPL = 0.84) with a long decay lifetime (τ= 0.36 ms) is obtained for the 1-naphthyl derivative. The complex with the anthryl ligand displays thermally activated delayed fluorescence (TADF) attributed to ISC between the S1 and T2 states, along with locally excited phosphorescence from the T1 state of the anthryl ligand.