The chemistry of copper(I)β-diketonate compounds. Part 4. Syntheses and characterization of CuXLn(X =β-diketonate or Cl, L = PMe3, n= 2 or 4; L = PEt3, n= 2)

Abstract

The salts [Cu(PMe₃)₄]⁺[CuCl₂]^– and [Cu(PMe₃)₄]⁺[β-diketonate]^–[β-diketonate = 1,1,1,5,5,5-hexafluoroacetylacetonate (hfacac), 1,1,1-trifluoroacetylacetonate (tfacac) or acetylacetonate (acac)] were prepared by the displacement of the co-ordinating anions Cl^– and β-diketonate from the copper(I) complexes [CuX(PMe₃)](X = Cl or β-diketonate) by addition of an excess of PMe₃. These species were characterized by a variety of spectroscopic methods including ³¹P NMR spectroscopy which revealed coupling between ³¹P and ^63,65Cu in the cation. Two examples were characterized in the solid state by single-crystal X-ray diffraction: [Cu(PMe₃)₄]⁺[CuCl₂]^–, space group P2₁3, a= 13.584(1)Å and Z= 12; [Cu(PMe₃)₄]⁺[hfacac]^–, space group Pmmn, a= 10.703(2), b= 15.077(3), c= 8.997(2)Å and Z= 2. The cations exhibit an approximately tetrahedral co-ordination environment and the anion [CuCl₂]^– is linear. The addition of excess of PEt₃ to [CuX(PEt₃)] resulted in formation of [CuX(PEt₃)₂] in contrast to the PMe₃ analogues. The compound [CuCl(PEt₃)₂] was found to be monomeric in benzene solution by cryoscopic molecular weight determination and has high volatility.