Phosphorescent Complexes of {Mo6I8}4+ and {W6I8}4+ with Perfluorinated Aryl Thiolates featuring Unusual Molecular Structures

A series of six novel cluster complexes [M6I8(SArf)6]2− (M=Mo or W; SArf=p‐SC6F4‐C6F5, p‐SC6F4Cl, or p‐SC6F4CF3) was prepared by exchange reactions between [Mo6I14]2− or [W6I14]2− and silver salts of the corresponding thiols and characterized by X‐ray single‐crystal diffraction and elemental analysis, NMR, ESI‐MS, and CV techniques. In the crystal structures all the thiolate ligands adopt an idiosyncratic orientation along one of the idealized three‐fold axes passing through two opposite μ3‐I ligands and the centers of two opposite faces of the M6 octahedra. This leads to shortened intramolecular C⋅⋅⋅I distances inside the cluster below 3.5 Å. The clusters exhibit red photoluminescence with relatively high quantum yield, up to 0.42 in the case of (Bu4N)2[W6I8(SC6F4CF3)6]. Moreover, all the compounds exhibit X‐ray luminescence; the close values of the maxima in the photo‐ and X‐ray induced emission spectra indicate that the luminescence is cluster‐centered.