Molecular design and screening of energetic nitramine derivatives

Six nitramines (N1-6) were designed with all possible arrangements of N-NO2 groups on a cyclic skeleton and structural optimization was performed using the density functional theory (DFT). We observed that all nitramines have high positive heats of formation proportionate to the number of N-NO2 groups in their molecular structure. Among the designed nitramines, N5 and N6 have crystal densities of 1.77 and 1.81 g cm(-3), respectively, which lead to reasonable respective detonation velocities (D = 8.70 and 9.07 km s(-1)) and detonation pressures (P = 33.23 and 36.57 GPa) comparable to those of RDX. To understand the relationship between sensitivity and molecular structure, bond dissociation energies, impact sensitivities (h 50), free space in crystal lattice, imbalance between the positive and negative surface potentials and heats of detonation (Q) were investigated. The comparable performance of N5 and N6 with RDX highlights the potential application of these nitramine derivatives as high energy materials and also supports the advantage of N-N bonds in the backbone and substitution of N-NO2 groups. Graphical Abstract Electrostatic potential on the 0.001 electron/bohr(3) molecular surface of N6.