Dual Luminescent Dinuclear Gold(I) Complexes of Terpyridyl‐Functionalized Alkyne Ligands and Their Efficient Sensitization of Eu^III and Yb^III Luminescence

Abstract

Abstract Reaction of (tpyC 6 H 4 C≡CAu) n {tpyC 6 H 4 C≡CH = 4′‐(4‐ethynylphenyl)‐2,2′:6′,2″‐terpyridine} with diphosphane ligands Ph 2 P(CH 2 ) x PPh 2 ( x = 2 dppe, 3 dppp, 4 dppb, 5 dpppen, 6 dpph) in CH 2 Cl 2 afforded the corresponding dual luminescent binuclear gold(I) complexes [(tpyC 6 H 4 C≡CAu) 2 (μ‐dppe)] ( 1 ), [(tpyC 6 H 4 C≡CAu) 2 (μ ‐ dppp)] ( 2 ), [(tpyC 6 H 4 C≡CAu) 2 (μ‐dppb)] ( 3 ), [(tpyC 6 H 4 C≡CAu) 2 (μ‐dpppen)] ( 4 ), [(tpyC 6 H 4 C≡CAu) 2 (μ‐dpph)] ( 5 ). Crystal structural analysis of complexes 1· 2CH 2 Cl 2 and 2· 2CH 2 Cl 2 show that the terpyridine moieties are free of coordination in these gold(I)‐acetylide‐phosphane complexes. Spectrophotometric titration between complex 1 and [Eu(tta) 3 ] (Htta = 2‐thenoyltrifluoroacetone) or [Yb(hfac) 3 (H 2 O) 2 ] (Hhfac = hexafluoroacetylacetone) gave a 2:1 ratio between Ln(β‐diketonate) 3 (Ln = Eu, Yb) units and the complex 1 moiety, indicating the formation of Au 2 Ln 2 complexes. Both the luminescence titrations and the luminescence quantum yields of Au 2 Ln 2 (Ln = Eu, Yb) solutions show that the energy transfer occurs efficiently from the binuclear gold(I) antennas 1 – 5 to Eu III and Yb III centers, and all complexes 1 – 5 are good energy donors for sensitization of visible and NIR luminescence of Eu III and Yb III ions.