Synthesis and properties of a new ketoiminate derivative of the 2,2,6,6-tetramethylheptane-3,5-dionate ligand to prepare volatile CVD precursors

The β-ketoimine (CH3)3CC(NH2)CHC(O)C(CH3)3 (1) was synthesized by amination with dry ammonia in the presence of TiCl4. M.p. = 131 °C. IR and 1H and 13C NMR spectroscopic characterization indicates that the structure of a solution of 1 is the ketone form, and a single-crystal X-ray diffraction study shows that the structure of 1 is the enaminoketone form. The reaction of 1 with copper(II) and nickel(II) salts in solution gave chelate metal complexes: Cu[(CH3)3CC(NH)CHC(O)C(CH3)3]2 (2), M.p. = 209 °C, and Ni[(CH3)3CC(NH)CHC(O)C(CH3)3]2 (3), M.p. = 267 °C. These complexes are volatile and sublime at 180–190 °C at 5 × 10−3 Torr. An X-ray diffraction study reveals that these metal complexes are monomeric and isostructural in the solid state. In compound 2, the Cu atom has a square coordination environment: Cu–O ≈ Cu–N = 1.91 Å, ∠O–Cu–N = 91.81 Å.

Graphical abstractThe β-aminoketone (CH3)3CC(NH2)CHC(O)C(CH3)3 was synthesized by amination of the relative β-diketone with dry ammonia in the presence of TiCl4. 1H and 13C NMR spectroscopy of the solution and a single-crystal X-ray diffraction study shows that the structure of 1 is the ketone form. The reaction of 1 with copper(II) and nickel(II) salts in solution gave ketoiminate metal chelates: Cu[(CH3)3CC(NH)CHC(O)C(CH3)3]2 (2) and Ni[(CH3)3CC(NH)CHC(O)C(CH3)3]2 (3). These complexes are volatile and sublimate at 180–190 °C at 10−2 Torr. An X-ray diffraction study reveals that these metal complexes are monomeric and isostructural in the solid state.Figure optionsDownload full-size imageDownload as PowerPoint slide