Products of the reaction between copper(I) phenoxide and triphenylphosphine

Article abstract of DOI:10.1016/S0020-1693(96)05189-4

Two phenolatocopper(I) derivatives, viz. [Cu₄(PPh₃)₄(OPh)₄] (1) and [Cu₂(PPh₃)₃(OPh)₂] (2), where Ph = C₆H₅, have been prepared by the addition of triphenylphosphine to copper(I) phenoxide, obtained from mesitylcopper(I) and phenol. Characterisation by means of crystal structure determination showed 1 to be a tetramer with a cubane-type Cu₄O₄ core in which Cu-O distances range from 2.05(2)-2.26(2) A. Complex 2 is a μ₂-phenoxide dimer in which one copper(I) centre is four-coordinated by two phenoxide and two triphenylphosphine ligands, while the other is coordinated by a single triphenylphosphine ligand and thus three-coordinated. Complex 1 crystallises as the solvate [Cu₄(PPh₃)₄(OPh)₄] · (C₆H₅CH₃)₂ in the monoclinic space group P2₁/c with a = 14.822(7), b = 23.160(4), c = 28.193(6) A, β = 98.64(2)°, V = 9569(5) A³ at - 90 °C and Z = 4; full-matrix least-squares refinement yielded R = 0.082 for 529 parameters and 3931 observed reflections. [Cu₂(PPh₃)₃(OPh)₂] (2) crystallises in the triclinic space group P1 with a = 13.948(4), b = 16.846(2), c = 12.480(3) A, α = 94.92(2), β = 110.45(2), γ = 95.96(2)°, V = 2709(2) A³ at - 120°C and Z = 2; full-matrix least-squares refinement yielded R = 0.063 for 328 parameters and 2507 observed reflections. The effect of increasing the PPh₃:CuOPh ratio on the stability of the phenoxide is discussed in terms of the coordination geometry and consequent accessibility of the metal to small molecules.