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.