Organogold(I) Fluorenyls: Excited-State Properties

A series of 2,7-disubstituted organogold(I) fluorenyls has been synthesized with full ground-state and optical characterization. Gold(I) is attached to the fluorenyl carbocycle through direct C-Au sigma-bonds, or through intervening alkynyl linkages. The new complexes are dual fluorescence and phosphorescence emitters, leading in some cases, to apparent white light emission. Excited-state dynamics have been measured by ns and ultrafast transient absorption spectroscopy, and rate constants for radiative and nonradiative decay, and intersystem crossing, have been obtained. Both fluorescence and phosphorescence originate from metal-perturbed ligand-centric charge-transfer excited states. Compositions of the relevant frontier orbitals were calculated from density-functional theory.