Luminescent Triphosphine Cyanide d10 Metal Complexes

Coinage metal cyanides efficiently react with a triphosphine. PPh2C6H4–PPh–C6H4PPh2 (P3). to give the complexes M­(P3)­CN, where M = Cu (1), Ag (2), and Au (3), which can further interact with coordinatively unsaturated metal centers [M­(P3)]+ to give the homobimetallic [(P3)­M–CN–M­(P3)]+X– [M = Cu (4a with X– = CF3SO3– and 4b with X– = BF4–), Ag (5)] or heterometallic [(P3)­Au–CN–Ag­(P3)]+ (6) species. Extension of this approach also provided the trinuclear complex [(P3)­Cu–NC–Au–CN–Cu­(P3)]+ (7). Compounds 1–5 were characterized in the solid state by X-ray crystallography. The NMR spectroscopic studies revealed that all of the complexes except 6 retain their structures in solution. The title compounds are luminescent in the solid state, with quantum yields ranging from 8 to 87%. The observed photoemission originates mainly from the metal-to-ligand charge-transfer states according to time-dependent density functional theory computational studies. The crystalline bimetallic Cu complexes 4a/4b demonstrate extremely high sensitivity of the emission intensity to molecular O2 (KSV1 = 639 atm–1 and LOD = 0.010% for 3 times the signal-to-noise ratio).