Linking of Cu^I Units by Tetrahedral Mo₂ E₂ Complexes (E=P, As)

The reaction of [Cp₂ Mo₂ (CO)₄ (μ,η^2:2 -E₂ )] (A: E=P, B: E=As, Cp=C₅ H₅ ) with the WCA-containing Cu^I salts ([Cu(CH₃ CN)₄ ][Al{OC(CF₃ )₃ }₄ ] (CuTEF, C), [Cu(CH₃ CN)₄ ][BF₄ ] (D) and [Cu(CH₃ CN)_3.5 ][FAl{OC₆ F₁₀ (C₆ F₅ )}₃ ] (CuFAl, E)) affords seven unprecedented coordination compounds. Depending on the E₂ ligand complex, the counter anion of the copper salt and the stoichiometry, four dinuclear copper dimers and three trinuclear copper compounds are accessible. The latter complexes reveal first linear Cu₃ arrays linked by E₂ units (E=P, As) coordinated in an η^2:1:1 coordination mode. All compounds were characterized by X-ray crystallography, NMR and IR spectroscopy, mass spectrometry and elemental analysis. To define the nature of the Cu⋅⋅⋅Cu⋅⋅⋅Cu interactions, DFT calculations were performed.