Alkyne complexes of copper(I) (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato): Syntheses and characterization of (eta(2)-bis(trimethylsilyl)acetylene) copper(I) (hfac), (mu-eta(2)-bis(trimethylsilyl)acetylene) bis(copper(I) (hfac)) and a series of (eta(2)-alkyne) Cu(hfac) complexes

The reaction of Cu2O with 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (Hhfac) in the presence of alkynes results in the formation of (eta(2)-alkyne) Cu(hfac), When using bis(trimethylsilyl)acetylene (BTMSA), both a mononuclear compound BTMSACu(hfac) (1) and a dinuclear complex BTMSA(Cu(hfac))(2) (2) can be isolated; each complex was characterized by X-ray crystallography, IR, H-1 and C-13 NMR spectroscopies. In 1, the BTMSA ligand is eta(2) bonded parallel to the Cu(beta-diketonate) plane, the trimethylsilyl groups are cis bent away from copper with small angles of deformation (theta(CCSi) = 157 and 171 degrees) and the C=C bond distance is 1.17 Angstrom. In 2, two BTMSACu(hfac) planes with a dihedral angle of 105.8 degrees are observed. The intramolecular Cu-Cu distance is only 2.800 Angstrom and the central axis of BTMSA is situated perpendicular to the Cu-Cu vector. A series of eta(2)-alkyne Cu(hfac) were synthesized and characterized by NMR and IR spectroscopy.