Self-Assembled Encapsulation of CuX 2 - (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, [Au 6 (Triphos) 4 (CuBr 2 )](OTf) 5 ·(CH 2 Cl 2 ) 3 ·(CH 3 OH) 3 ·(H 2 O) 4 ( 1 ) and [Au 6 (Triphos) 4 (CuCl 2 )](PF 6 ) 5 ·(CH 2 Cl 2 ) 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 CuX 2 - (X = Br or Cl) unit suspended between two Au(I) centers without the involvement of bridging ligands. These colorless crystals display green luminescence (λ em = 527 nm) for ( 1 ) and teal luminescence (λ em = 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.