The trigonal planar Au(I) complex Cs-8[Au(TPPTS)(3)].5.25H(2)O, TPPTS = tris-sulfonatophenyl phosphine, has been structurally characterized. The X-ray data for the triclinic crystal, P (1) over bar, are a 13.7003(4) Angstrom, b = 18.0001(6) Angstrom, c = 18.2817(2) Angstrom, alpha = 100.249(2)degrees, beta = 99.593(2)degrees, gamma = 109.818(2)degrees, V = 4046.3(2) Angstrom(3), Z = 2. The complex has Au-P distances of 2.374(6), 2.394(5), and 2.417(5) Angstrom. A network of bonding has been found involving the Cs+ ions, the sulfonate groups of the ligands, and the H2O solvent molecules. Luminescence studies of [Au(TPPTS)(3)](8-) and (TPA)(3)AuCl, TPA = 1,3,5-triaza-7-phosphaadamantane, in the solid state and in solution are discussed and quenching studies of the luminescence of [Au(TPPTS)(3)](8-) are reported with alkyl halides and oxygen. (C) 2003 Elsevier B.V. All rights reserved.