Synthesis, characterization and photophysical studies of luminescent dinuclear and trinuclear copper(I) alkynyl phosphines

Luminescent polynuclear copper(I) alkynyl complexes, including two trinuclear bicapped complexes, [Cu₃(μ-dppm)₃(μ ₃-η ¹-C≡CC₆H ₄ ⁿ C₄H₉)₂]BF₄ (1) and [Cu₃(μ-dppm)₃(μ ₃-η ¹-C≡CC₆H₄C≡CC₆H₅)₂]BF₄ (2), as well as two dinuclear complexes, [Cu₂(PPh₂Me)₄(μ ₂-η ¹-C≡CC₆H ₄ ⁿ C₄H₉)₂] (3) and [Cu₂(PPh₂Me)₄(μ ₂-η ¹-C≡CC₆H₄C≡CC₆H₅)₂] (4), have been successfully synthesized and characterized. The carbazole moiety has also been incorporated into the alkynyl skeleton to prepare the trinuclear bicapped complex, [Cu₃(μ-dppm)₃(μ ₃-η ¹-C≡CC₆H₄-Cz)₂]BF₄ (Cz = carbazole) (5). The crystal structure of 3 has also been determined. The complexes exhibit high-energy intraligand (IL) π → π* absorption bands typical of the corresponding phosphine and alkynyl ligands. The complexes show intense luminescence originated from a ³LMCT [RC≡C^- → Cu_n] state (n = 2, 3), with mixing of a triplet metal cluster-centered ds/dp state. Copyright © 2013 Springer Science+Business Media New York.