Self-Assembled Encapsulation of CuX2 – (X = Br, Cl) in a Gold Phosphine Box-like Cavity with Metallophilic Au–Cu Interactions

Synthetic routes to the crystallization of two new box-like complexes, [Au6(Triphos)4(CuBr2)]­(OTf)5·(CH2Cl2)3·(CH3OH)3·(H2O)4 (1) and [Au6(Triphos)4 (CuCl2)]­(PF6)5·(CH2Cl2)4 (2) (triphos = bis­(2-diphenylphosphinoethyl)­phenylphosphine), have been developed. The two centrosymmetric cationic complexes have been structurally characterized through single-crystal X-ray diffraction and shown to contain a CuX2 – (X = Br or Cl) unit suspended between two Au­(I) centers without the involvement of bridging ligands. These colorless crystals display green luminescence (λem = 527 nm) for (1) and teal luminescence (λem = 464 nm) for (2). Computational results document the metallophilic interactions that are involved in positioning the Cu­(I) center between the two Au­(I) ions and in the luminescence.