Design and exploration of 5-nitro-3-trinitromethyl-1H-1,2,4-triazole and its derivatives as energetic materials.

According to the fact that 5-nitro-3-trinitromethyl-1H-1,2,4 triazole (NTNMT) is a successful, good explosive, energetic groups such as -CH, -NH, -NHNO, -NO, -ONO, -NF, -CN, -NC, -N groups were introduced into NTNMT and their oxygen balance was at about zero. The energetic properties, detonation performance, and sensitivity were studied at the B3LYP/6-31G** level of density functional theory to seek for possible high energy density compounds. The effects of substituent groups on heat of formation (HOF), density ρ, detonation velocity D, detonation pressure P, detonation energy Q, and sensitivity (evaluated using oxygen balance OB, the nitro group charges -Q, and bond dissociation energies BDE were studied and discussed.

Theoretical studies of -NH₂ and -NO₂ substituted dipyridines.

In this work, the experimental synthesized bipyridines 3,3'-Dinitro-2,2'-bipyridine (DNBPy), 3,3'-Dinitro-2,2'-bipyridine-1,1'-dioxide (DNBPyO), and (3-Nitro-2-pyridyl)(5-nitro-2-pyridyl) amine (NPyA), and a set of designed dipyridines that have similar frameworks but different linkages and substituents with NPyA were studied theoretically at the B3LYP/6-31G* level of density functional theory. The gas-phase heats of formation were predicted based on the isodesmic reactions and the condensed-phase heats of formation and heats of sublimation were estimated in the framework of the Politzer approach. The crystal densities have been computed from molecular packing.

Density functional theory study of high-pressure effect on crystalline 4,4',6,6'-tetra(azido)hydrazo-1,3,5-triazine.

Periodic density functional theory calculations are performed to study the hydrostatic compression effects on the structure, electronic, and thermodynamic properties of the energetic polyazide 4,4',6,6'-tetra(azido)hydrazo-1,3,5-triazine (TAHT) in the range of 0-100 GPa. At the ambient pressure, the local density approximation/Ceperley-Alder exchange-correlation potential parameterized by Perdew and Zunger relaxed crystal structure compares well with the experimental results. The predicted heat of sublimation is 38.

Theoretical investigations on structure, density, detonation properties, and sensitivity of the derivatives of PYX.

The -NH(2), -NO(2), -N(3), -NHNO(2), and -ONO(2) substitution derivatives of PYX (2,6-bis(picrylamino)-3,5-dinitropyridine) were studied at the B3LYP/6-31G** level of density functional theory. The sublimation enthalpies and heats of formation (HOFs) in gas phase and solid state of these compounds were calculated. The theoretical predicted density (ρ), detonation pressure (P), and detonation velocity (D) showed that these derivatives have better detonation performance than PYX.

Crystal structure, detonation performance, and thermal stability of a new polynitro cage compound: 2, 4, 6, 8, 10, 12, 13, 14, 15-nonanitro-2, 4, 6, 8, 10, 12, 13, 14, 15-nonaazaheptacyclo [5.5.1.1(3, 11).1 (5, 9)] pentadecane.

A new polynitro cage compound 2, 4, 6, 8, 10, 12, 13, 14, 15-nonanitro-2, 4, 6, 8, 10, 12, 13, 14, 15-nonaazaheptcyclo [5.5.1.

A theoretical study on the reaction mechanism of O2 with C4H9• radical.

Ab initio calculations have been performed using the complete basis set model (CBS-QB3) to study the reaction mechanism of butane radical (C(4)H(9)•) with oxygen (O(2)). On the calculated potential energy surface, the addition of O(2) to C(4)H(9)• forms three intermediates barrierlessly, which can undergo subsequent isomerization or decomposition reaction leading to various products: HOO• + C(4)H(8), C(2)H(5)• + CH(2)CHOOH, OH• + C(3)H(7)CHO, OH• + cycle-C(4)H(8)O, CH(3)• + CH(3)CHCHOOH, CH(2)OOH• + C(3)H(6). Five pathways are supposed in this study.

Comparative theoretical studies of energetic azo s-triazines.

In this work, the properties of the synthesized high-nitrogen compounds 4,4',6,6'-tetra(azido)azo-1,3,5-triazine (TAAT) and 4,4',6,6'-tetra(azido)hydrazo-1,3,5-triazine (TAHT), and a set of designed bridged triazines with similar bridges were studied theoretically to facilitate further developments for the molecules of interests. The gas-phase heats of formation were predicted based on the isodesmic reactions by using the DFT-B3LYP/AUG-cc-PVDZ method. The estimates of the condensed-phase heats of formation and heats of sublimation were estimated in the framework of the Politzer approach.

DFT studies on a high energy density cage compound 4-trinitroethyl-2,6,8,10,12-pentanitrohezaazaisowurtzitane.

Polynitro cage compound 4-trinitroethyl-2,6,8,10,12-pentanitrohexaazaisowurtzitane has the same framework with but higher stability than CL-20 and is a potential new high energy density compound (HEDC). In this paper, the B3LYP/6-31G(d,p) method of density functional theory (DFT) has been used to study its heat of formation, IR spectrum, and thermodynamic properties. The stability of the compound was evaluated by the bond dissociation energies.

Theoretical investigations of a high density cage compound 10-(1-nitro-1, 2, 3, 4-tetraazol-5-yl)) methyl-2, 4, 6, 8, 12-hexanitrohexaazaisowurtzitane.

A new polynitro cage compound with the framework of HNIW and a tetrazole unit, i.e., 10-(1-nitro-1, 2, 3, 4-tetraazol-5-yl)) methyl-2, 4, 6, 8, 12-hexanitrohexaazaisowurtzitane (NTz-HNIW) has been proposed and studied by density functional theory (DFT) and molecular mechanics methods.

Theoretical prediction of properties of aliphatic polynitrates.

Aliphatic polynitrates are studied using the density functional theory B3LYP method with basis set 6-31G*. The assigned infrared spectrum is obtained and is used to compute the thermodynamic properties based on the frequencies scaled by 0.96 and the principle of statistic thermodynamics.

Looking for high energy density compounds applicable for propellant among the derivatives of DPO with -N3, -ONO2, and -NNO2 groups.

The derivatives of DPO (2,5-dipicryl-1,3,4-oxadiazole) are optimized to obtain their molecular geometries and electronic structures at the DFT-B3LYP/6-31G* level. The bond length is focused to primarily predict thermal stability and the pyrolysis mechanism of the title compounds. Detonation properties are evaluated using the modified Kamlet-Jacobs equations based on the calculated densities and heats of formation.

A theoretical study on the vibrational spectra and thermodynamic properties for the nitro derivatives of phenols.

The nitro derivatives of phenols are optimized to obtain their molecular geometries and electronic structures at the DFT-B3LYP/6-31 G* level. Their IR spectra are obtained and assigned by vibrational analysis and are reliable compared with the experimental results. Based on the frequencies scaled by 0.

Packing structures and periodic band calculations on DPO (2,5-dipicryl-1,3,4-oxadiazole).

Molecular mechanics (MM) method with Compass and Dreiding force fields is used to predict molecular packing for DPO among the 7 most possible space groups (P2(1)/c, P-1, P2(1)2(1)2(1), P2(1), Pbca, C2/c, and Pna2(1)), respectively. Then, periodic band calculations are performed on the predicted crystals using the DFT-GGA-RPBE method. Obtained density of state (DOS) shows that C-O, CN-O(2) and N-N bonds are possibly the trigger bond during thermolysis.

Theoretical investigation on structures, densities, detonation properties, and the pyrolysis mechanism of the derivatives of HNS.

The derivatives of 2,2',4,4',6,6'-hexanitrostilbene (HNS) are optimized to obtain their molecular geometries and electronic structures at the DFT-B3LYP/6-31G* level. Detonation properties are evaluated using the modified Kamlet-Jacobs equations based on the calculated densities and heats of formation. It is found that there are good linear relationships between the density, detonation velocity, detonation pressure, and number of nitro, amino, and hydroxy groups.

Computational studies on polynitrohexaazaadmantanes as potential high energy density materials.

Polynitrohexaazaadamantanes (PNHAAs) have been the subject of much recent research because of their potential as high energy density materials (HEDMs). The B3LYP/6-31G method was employed to evaluate the heats of formation (HOFs) for PNHAAs by designing isodesmic reactions. The HOFs are found to be correlative with the number (n) and the space orientations of nitro groups.

Theoretical studies on the vibrational spectra, thermodynamic properties, detonation properties, and pyrolysis mechanisms for polynitroadamantanes.

To look for high energy density materials (HEDM), the relationships between the structures and the performances of polynitroadamantanes (PNAs) were studied. The assigned infrared spectra of PNAs obtained at the density functional theory (DFT) B3LYP/6-31G level were used to compute the thermodynamic properties on the basis of the principle of statistical thermodynamics. The thermodynamic properties are linearly related with the number of nitro groups as well as with the temperatures.

Quantitative structure-activity relationships of nitroaromatics toxicity to the algae (Scenedesmus obliguus).

The DFT-B3LYP method, with the basis set 6-311G( * *), was employed to calculate the molecular geometries and electronic structures of 25 nitroaromatics. The acute toxicity (-lgEC(50)) of these compounds to the algae (Scenedesmus obliguus) along with hydrophobicity described by logK(OW), and two quantum chemical parameters-energy of the lowest unoccupied molecular orbital, E(LUMO), and the charge of the nitro group, [ForQ(NO2), were used to establish the quantitative structure-activity relationships (QSARs). For 18 mononitro derivatives, the hydrophobicity parameter logK(OW) could interpret the toxic mechanism successfully.