Chemistry of copper(I) β-diketonate complexes

A series of copper(I) compounds of the general formula (fod)CuL, where fod = 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octanedione, and L  PMe 3 , PEt 3 , 1,5-cyclooctadiene (1,5-COD), vinyltrimethylsilane (VTMS), 2-butyne, bis(trimethylsilyl)acetylene (BTMSA), have been prepared by the reaction of Na[fod] with CuCl in the presence of the appropriate amount of the Lewis base, L. All the compounds were characterized by elemental analysis, 1 H, 13 C, 19 F, 31 P and IR spectroscopies. The spectroscopic data are consistent with the chelation of the β- diketonate ligand through its oxygen atoms to the copper(I) center. The analytical data are consistent with the empirical formula (fod)CuL. One compound, (fod)CuPMe 3 , was characterized in the solid-state by single-crystal X-ray diffraction which confirmed the empirical formula and revealed the monomeric nature of this species in the solid state. The distorted trigonal planar coordination environment observed for this species is common to these species. The CuO distances are significantly different within the limits of error on the data possibly as a result of inductive effects of the different β-diketonate substituents. Crystal data: Triclinic space group P 1, a = 10.052(2) A, b = 11.871 (2) A, c = 16287(3) A, α = 109.84(1)°, β = 92.18(2)°, γ = 90.34(2)°, V = 1826.5(6) A 3 , Z = 4, R F , = 7.09% and R wF = 7.28%. Hot- and cold-wall chemical vapor deposition experiments revealed that these species are generally not suitable as precursors for the deposition of copper due to their low thermal stability. While pure copper films could be deposited, as determined by Auger electron spectroscopy, from the compounds (fod)CuL, where L = PMe 3 , 2-butyne and BTMSA, heating the precursors to increase their vapor pressures resulted in significant thermal decomposition in the source reservoir. As a result, deposition rates of only 100 A/min were achieved. No selectivity was observed on W versus SiO 2 substrates under the conditions employed. The other compounds, (fod)CuL, where L = 1,5-COD, VTMS, were too thermally unstable for CVD experiments.