Tetranuclear (phosphane)(thiolato)gold(I) complexes: synthesis, characterization and photoluminiscent properties

Abstract

The reactions of the tetraphosphane donor ligand (Ph2PCH2)2NCH2CH2N(CH2PPh2)2 with the gold precursors [AuCl(tht)] or [Au(C6F5)(tht)] (tht = tetrahydrothiophene) leads to complexes [Au4R4{(Ph2PCH2)2NCH2CH2N(CH2PPh2)2}] [R = Cl (1) or C6F5 (2)]. Further substitution of the chlorine atoms in 1 by the corresponding 4-substituted benzenethiolates gives rise to the tetranuclear (phosphane)(thiolato)gold(I) complexes [Au4(S-C6H4-X)4{(Ph2PCH2)2NCH2CH2N(CH2PPh2)2}] [X = F (3), MeO (4), Me (5) and NO2 (6)]. Complexes 2 and 4 were characterized by X-ray diffraction studies showing Au···Au interactions in the case of complex 4. Complexes 3-6 display intense emissions in the solid state at 77 K with lifetimes in the microsecond range. The observed phosphorescent emissions are attributed to metal-to-ligand charge-transfer transitions. Nevertheless, the influence in the emission energies of gold-gold interactions or the contribution of the substituent in the 4-position of the benzenethiolate ring to the excited state cannot be neglected. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)