Theoretical studies on BTA-Metal (M=Ni, Cu) Complexes as High Energy Materials

Metal complexes of Nickel and Copper with the dianion of bidentate chelating agent BTA [N,N-bis(1(2)H-tetrazole-5-yl)-amine] along with NH3 and NH2NO2 ligands were designed. A total of four metal complexes having the compositions such as M(BTA)(NH3)(NH2NO2) and M(BTA)(NH2NO2)2 where M is the metal atom, were formulated and subjected to detailed theoretical study to explore their energetic properties. Density Functional Theory (DFT) was used to predict the optimized geometry of the complexes at TPSS / 6-311G(d,p) level. The heats of formation of the metal complexes were determined using atomization method. Crystal densities of the salts were predicted using the data obtained at B3PW91 /6-31G(d,p) level utilizing the wave function analysis (WFA) program. Results indicate that all the designed compounds possess density in the range of 2.18–2.25 g cm−3. This is the remarkable feature of the title compounds because loading density is one of the desired properties for increasing the detonation performance of energetic materials. The calculated impact sensitivities (h50, cm) show that the three of the designed compounds are comfortably insensitive towards impact (h50,cm ∼42) in comparison to the experimentally determined values for the commercially used powerful explosives such as RDX (24–28 cm) and HMX (26–32 cm). Ni(BTA)(NH2NO2)2, the fourth designed compound has a value almost similar to that of RDX and HMX. The calculated detonation parameters D (detonation velocity) and P (detonation pressure) are predicted to be in the range of 7.7–8.5 km s−1 and 29.5–36.1 GPa, respectively. Results obtained in the present study predict that the designed compounds can be used as high energy density materials (HEDs).