Dual Luminescent Dinuclear Gold(I) Complexes of Terpyridyl‐Functionalized Alkyne Ligands and Their Efficient Sensitization of EuIII and YbIII Luminescence

Abstract

AbstractReaction of (tpyC6H4C≡CAu)n {tpyC6H4C≡CH = 4′‐(4‐ethynylphenyl)‐2,2′:6′,2″‐terpyridine} with diphosphane ligands Ph2P(CH2)xPPh2 (x = 2 dppe, 3 dppp, 4 dppb, 5 dpppen, 6 dpph) in CH2Cl2 afforded the corresponding dual luminescent binuclear gold(I) complexes [(tpyC6H4C≡CAu)2(μ‐dppe)] (1), [(tpyC6H4C≡CAu)2(μ‐dppp)] (2), [(tpyC6H4C≡CAu)2(μ‐dppb)] (3), [(tpyC6H4C≡CAu)2(μ‐dpppen)] (4), [(tpyC6H4C≡CAu)2(μ‐dpph)] (5). Crystal structural analysis of complexes 1·2CH2Cl2 and 2·2CH2Cl2 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(H2O)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 Au2Ln2 complexes. Both the luminescence titrations and the luminescence quantum yields of Au2Ln2 (Ln = Eu, Yb) solutions show that the energy transfer occurs efficiently from the binuclear gold(I) antennas 1–5 to EuIII and YbIII centers, and all complexes 1–5 are good energy donors for sensitization of visible and NIR luminescence of EuIII and YbIII ions.