Mass spectrometric study of the thermal decomposition mechanism of vapors of 2,2,6,6-tetramethyl-3-iminoheptane-5-one and its copper(II) complex

Thermal conversions of vapors of ketoimine C(CH3)3C(NH)CH2C(O)C(CH3)3 (Htmha = 2,2,6,6-tetramethyl-3-iminoheptane-5-one) and its chelate coordination compound with copper Cu(tmha)2 is studied by in situ mass spectrometry in a vacuum and in the presence of hydrogen. Experiments are carried out under conditions close to low pressure chemical vapor deposition at the evaporator temperature of 130 °C and the reactor temperature range 130–500 °C. It is found that compounds are monomeric in the gas phase. Based on temperature dependences of the composition of primary gaseous products, the mechanism of thermal decomposition is proposed. The decomposition of ketoimine on the heated surface begins at 350 ± 10 °C and proceeds by the elimination of terminal groups. Its copper complex decomposes in two directions and yields both molecular and radical products. The latter provide the assumption that metallic copper forms as the only one solid product. The results obtained are compared with those for copper dipivaloylmethanate(2,2,6,6-tetramethylheptane-3,5-dionate).

Graphical abstractThermal conversions of vapors of ketoimine (CH3)3CC(NH)CH2C(O)C(CH3)3 and its chelate complex with copper is studied by in situ mass spectrometry in a vacuum and in the hydrogen presence in the temperature range 130–500 °C. Based on temperature dependences of the composition of primary gaseous products, the mechanism of thermolysis is proposed. The decomposition of ketoimine begins at 350 ± 10 °C and proceeds by the elimination of terminal groups. Its copper complex decomposes in two directions and yields both molecular and radical products.Figure optionsDownload full-size imageDownload as PowerPoint slide