Determination of the values of ΔfHo of aluminum organic compounds using the calibration dependencies and mechanism of their thermal decomposition.

In the present work the calibration dependencies for the values of ΔraHo(Xn) of atomization of aluminum organic compounds (AOC), as well as the values of RMSE Ali and σ Ali , are determined using the 5 DFT (M062X, B3LYP, wB97XD, M08HX, and MN15 at 6–311++G(d,p) level of theory) and two composite (CBSQB3 and G3B3) approaches. The determined calibration dependencies are used for the calculation of the values of Δ f H o ( X n ) rec of the AOC and analysis of the thermochemistry of their reactions of association and decomposition. The results indicate that the most thermochemically favorable pathways of decomposition of considered AOC are the reactions of formation of hydride bond and unsaturated hydrocarbons (R27–R30). The values of activation energy for these reactions are estimated 120–130 kJ/mol. At the same time, this mechanism cannot be applied for the decomposition of Al(CH 3 ) 3 and its dimer (Al 2 (CH 3 ) 6 ). In this case, the formation of C 2 H 6 (reaction R28) is considered more appropriate.