Theoretic Studies Of The Structures And Properties Of Energetic High-nitrogen Compounds

The structures and properties of carbon-bridged diiminotetrazole derivatives, nitrogen-bridged diiminotetrazole derivatives, tetraazaadamantane derivatives, and four nitro or/and nitrate adamantane derivatives were studied systematically using the DFT-B3LYP method, and according to the quantitative criteria of energy and stability of a high-energy density compound (HEDC), the potential candidates of HEDCs were selected. Main parts of the study are as follows:1. The structures of five series of carbon-bridged diiminotetrazole derivatives were optimized using the B3LYP/6-31G** method and their single point calculations were performed to obtain their energies of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). The isodesmic reactions of the derivatives were designed to calculate their heats of formation (HOFs). The effects of different substituents and bridges on their HOFs were discussed. Crystal densities of the derivatives were calculated from molecular weight divided by mean molecular volume. Their detonation velocities and pressures were evaluated using the semiempirical Kamlet-Jacobs equations. The detonation properties of different derivatives were compared and discussed. The bond dissociation energy (BDE) of each possible thermal trigger bond of all the derivatives was calculated by the UB3LYP/6-31G** method, and their thermal stabilities were compared.2. The optimizations and the single point calculations were performed to get the energies of the HOMO and LUMO of five series of nitrogen-bridged diiminotetrazole derivatives. Their HOFs were calculated via designing isodesmic reactions and the effects of different substituents and nitrogen bridges on their HOFs were discussed. Their crystal densities were estimated from molecular weight divided by mean molecular volume. Their detonation velocities and pressures were evaluated using the semiempirical Kamlet-Jacobs equations. The detonation properties of different derivatives were compared and discussed. The BDE of each possible thermal trigger bond of all the derivatives was calculated and compared to judge their thermal stabilities.3. The electronic structural parameters of ten series of tetraazaadamantane derivatives were obtained by the optimizations and the single point calculations. Designing isodesmic reactions were used to estimate their HOFs and the effects of different substituents and their numbers on the HOFs were compared. Crystal densities of the derivatives were calculated via molecular weight divided by mean molecular volume. The semiempirical Kamlet-Jacobs equations were used to calculate their detonation velocities and pressures, and their detonation properties were compared and discussed. Each possible thermal trigger bond of all the derivatives was broken to calculate its BDE and their thermal stabilities were compared.4. The structural optimizations and the single point calculations on four nitro or/and nitrate adamantane derivatives were performed to get their electronic structural parameters. The isodesmic reactions of the derivatives were designed to calculate their HOFs. The relative order of their HOFs was compared and discussed. Their crystal densities were estimated from molecular weight divided by mean molecular volume. Their detonation velocities and pressures were evaluated using the semiempirical Kamlet-Jacobs equations. The detonation properties of different derivatives were compared and discussed.