The processes of thermal decomposition of aluminium(II1) and scandium(II1) acetylacetonates (Al(aa)3 and Sc(aa)-,)were investigated in the 160-650°C temperature range using a high-temperature molecular beam source with mass spectrometric sampling of the gas phase composition directly at the outlet from the reaction zone. A scheme of thermal decomposition of aluminium(II1) and scandium(II1) acetylacetonates vapour is suggested. It is established that the common mechanism of thermolysis of these complexes is due to the commonness of electronic structure of ions Mg 2f, A I '+, Sc " and Hf 4+. According to the scheme, the process proceeds along three parallel routes, one of them being possible only for complexes possessing more than two Iigands; in this case the gaseous products resulting from cyclic dimerization of ligand fragments are formed. The influence of oxygen and hydrogen on the composit~on of the gaseous products and the mechanism of ther~~iolysis of the complexes vapour are also established. From temperature curves, the effective values of kinet~c parameters in Arrhenius equation are calculated for the first order reaction.

No abstract

No abstract

Thermal properties of oxygen-, phosphorus-, and halogen-free dimethylgold(III) diethyldithiocarbamate complex (CH 3 ) 2 AuS 2 CN(C 2 H 5 ) 2 (gold, dimethyl(diethylcarbamodithioato -S,S′)-) having excellent storage stability and the mechanism of its decomposition to elemental gold were studied. Saturated vapor pressure was found to be~10 10−1 Torr at 50-90°C. Decomposition of the vapor on the surface starts at T=210°C. The temperature dependence of gas phase composition was studied using the original mass spectrometric technique, it was established that the decomposition of the compound on the surface in vacuum follows three main pathways. Two of them result in the formation of elemental gold, saturated C2-C4 alkanes and (1) protonated ligand or (2) methylated ligand. The third one results in elemental gold and gaseous products: C2-C3 alkylmercaptanes and CH 3 SCN(C 2 H 5 ) 2 . The formation of gold as a sole solid product within the temperature range 210-240°C was confirmed by X-ray photoelectron spectroscopy analysis. It was shown that the compound exhibits the best combination of volatility, thermal, and storage stability among volatile organogold complexes and thus it may be a promising precursor for obtaining gold films by chemical vapor deposition.