Luminescent Triphosphine Cyanide d10 Metal Complexes

Coinage metal cyanides efficiently react with a triphosphine. PPh2C6H4-PPh-C6H4PPh2 (P-3). to give the complexes M(P-3)CN, where M = Cu (1), Ag (2), and Au (3), which can further interact with coordinatively unsaturated metal centers [M(P-3)](+) to give the homobimetallic [(P-3)M-CN-M(P-3)]X-+(-) [M = Cu (4a with X = CF3SO3- and 4b with X- = BF4-), Ag (5)] or heterometallic [(P-3)Au-CN-Ag(P-3)](+) (6) species. Extension of this approach also provided the trinuclear complex [(P-3)Cu-NC-Au-CN-Cu(P-3)](+) (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 O-2 (K-SV1 = 639 atm(-1) and LOD = 0.010% for 3 times the signal-to-noise ratio).