Theoretical studies on heats of formation, group interactions, and bond dissociation energies in neopentyl difluoroamino compounds

The heats of formation (HOFs) were calculated for a series of neopentyl difluoroamino compounds by using density functional theory (DFT) method with 6-311G∗∗ basis set, as well as semi-empirical methods. In the isodesmic reactions designed for the computation of HOF, the neopentane was chosen as a reference compound. The HOFs increase smoothly as -ONO2 groups being replaced by -NF2 and -NO2. However, HOFs increase dramatically as -ONO2 groups being replaced by -N(NO2)CH3 and -N3 groups. The variations of HOFs are different with different substituents. The semi-empirical MO (MNDO, AM1, and PM3) methods did not produce accurate and reliable results for the HOFs of the title compounds. The relative stability of the title compounds was evaluated based on the calculated HOFs, the energy gaps between the frontier orbitals and the bond order of C-R bond (C-NF2, C-ONO2, C-NO2 and C-N3). The magnitudes of intramolecular group interactions were predicted through the disproportionation energies. Thermal stabilities were evaluated via bond dissociation energies (BDE) at the B3LYP/6-311G∗∗ level. These results provide basic information for the molecular design of novel high energetic density materials.