A Multistimuli-Responsive Photoluminescent Au(I) Complex with a PNN-Type Ligand

Reaction of AuCN with a PNN-type ligand dppmaphen (N-(diphenylphosphanylmethyl)-2-amino-1,10-phenanthroline) yielded a novel monoprotonated trinuclear Au(I) complex [Au₃H(dppmaphen)₂(CN)₄] (1). Upon excitation at 368 nm, compound 1 emitted phosphorescence at 524 nm at room temperature and an additional phosphorescent band around 610 nm at lower temperatures and may function as a low-temperature thermometer. Compound 1 also exhibited reversible PL changes from green to yellow upon grinding and exposure to organic solvents, which is attributed to the destruction and rebuilding of voids in its crystal structure. Upon exposure to gaseous ammonia, up to 8 equiv of NH₃ were adsorbed, leading to the switching-off of the PL, and accompanied by a change in crystalline phase.