It has long been established by Khan that the superoxide anion, O2-, generates singlet oxygen, O21Δg,
during dismutation. Auranofin, gold-phosphine thiols, β-Carotene, and metal-sulfur compounds can
rapidly quench singlet O2. The quenching of the O21Δg, which exists at 7752 cm-1 above the ground state
triplet, may be due to the direct interaction of the singlet O2 with gold(I) or may require special ligands
such as those containing sulfur coordinated to the metal. Thus we have been examining the excited state
behavior of gold(I) species and the mechanisms for luminescence. Luminescence is observed under
various conditions, with visible emission ranging from blue to red depending on the ligands coordinated
to gold(I). Triplet state emission can be found from mononuclear three coordinate Au(I) species, including
species which display this behavior in aqueous solution. A description is given of the luminescent three
coordinate TPA (triazaphosphaadamantane) and TPPTS (triphenylphosphine-trisulfonate) complexes,
the first examples of water soluble luminescent species of gold(I).