Structures and Phosphorescence Properties of Triphosphine-Supported Au2Ag2 and Au8Ag4 Alkynyl Cluster Complexes

The synthesis, structure, and phosphorescence properties of two families of triphosphine-supported Au(I)-Ag(I) heteronuclear alkynyl cluster complexes with unprecedented Au2Ag2 and Au8Ag4 cluster structures are described. The phosphorescence emission over the whole visible light region was systematically tuned through modification of the electronic effects in aromatic acetylide ligands to attain bright phosphorescence with different luminescent colors. Introduction of electron-withdrawing CF3 to phenylacetylides results in the emission spectral blue-shift, while it shows progressive redshift upon introducing electron-donating But, OMe, or NMe2. As demonstrated from both experimental and theoretical studies, the phosphorescence arises primarily from (LLCT)-L-3/(IL)-I-3 and Au2Ag2/Au8Ag4 cluster-centered (3)[d-->p] transitions.