Luminescence properties of phosphinegold(I) halides and thiolates

Mono- and multi-nuclear phosphinegold(I) compounds, incorporating halide and thiolate ligands, have attracted considerable interest owing to their unique luminescence properties. Assignments for the observed luminescence are summarized in terms of metal-centered transitions, intra-ligand transitions, and ligand-to-gold charge transfer transitions. Furthermore, Au…Au (i.e. aurophilic) interactions, sometimes observed in their solid-state structures, can also influence the observed luminescence characteristics. The aim of this review is to delineate the luminescent properties of the phosphinegold(I) halides and phosphinegold(I) thiolates, in particular where there is some debate as to the underlining optical processes responsible for this phenomenon and to relate these assignments to different structural motifs, in particular to the presence of aurophilic (Au…Au) interactions.