Emissive Biphenyl Cyclometalated Gold(III) Diethyl Dithiocarbamate Complexes
datasetposted on 06.07.2016, 17:19 by Lakshmi Nilakantan, David R. McMillin, Paul R. Sharp
We report here a series of emissive biphenyl cyclometalated gold(III) diethyl dithiocarbamate complexes having H, CF3, OMe, and tBu substitutions on the biphenyl moiety. Synthesis of these complexes was accomplished by a single-step reaction of the appropriate dilithio-biphenyl reagent with Au(dtc)Cl2 (dtc = diethyl dithiocarbamate). All four complexes exhibit weak room-temperature phosphorescence in solution and much more intense phosphorescence in the solid state and in low-temperature glasses with lifetimes in the microseconds. From experimental data and computational modeling, the emission originates mainly from a metal-perturbed 3(π–π*) state of the biphenyl moiety with a minor contribution from ligand-to-ligand charge transfer. Weak solution emission is attributed to deactivation via a distorted charge-transfer state that is less accessible in the solid state or in a low-temperature glass.