Theoretical Investigation of Energetic Salts with Pentazolate Anion

Abstract

Energetic salts based on pentazolate anion (cyclo-N5−) have attracted much attention due to their high nitrogen contents. However, it is an enormous challenge to efficiently screen out an appropriate cation that can match well with cyclo-N5−. The vertical electron affinity (VEA) of the cations and vertical ionization potential (VIP) of the anions for 135 energetic salts and some cyclo-N5− salts were calculated by the density functional theory (DFT). The magnitudes of VEA and VIP, and their matchability were analyzed. The results based on the calculations at the B3LYP/6-311++G(d,p) and B3LYP/aug-cc-pVTZ levels indicate that there is an excellent compatibility between cyclo-N5− and cation when the difference between the VEA of cation and the VIP of cyclo-N5− anion is −2.8 to −1.0 eV. The densities of the salts were predicted by the DFT method. Relationship between the calculated density and the experimental density was established as ρExpt = 1.111ρcal − 0.06067 with a correlation coefficient of 0.905. This regression equation could be in turn used to calibrate the calculated density of the cyclo-N5− energetic salts accurately. This work provides a favorable way to explore the energetic salts with excellent performance based on cyclo-N5−.

Identification of Potential Electrolyte Additives via Density Functional Theory Analysis

“…We further used the electron affinity (EA) as the next criteria for a more comprehensive analysis on the reducibility [9,24] . Both the vertical electron affinity VEA=E(N)−E(N+1) and adiabatic electron affinity AEA=E(N)−E opt (N+1) were calculated for the target structures and VC [25–26] . Meanwhile, the solvent effect was considered in calculations for better description on the redox potential in solution phase (see Table S2 for the detailed results).…”

“…Similar to the proposal mentioned above, incorporating a double bond into the fivemembered ring results in significantly lowered LUMO energy (16 vs 17), and the presence of alkyl groups/one chlorine makes little perturbation on the LUMO energy (19, 20 vs 18). Compare to these molecules, changing the carbonyl group into carbonothioate group, incorporating an extra-strong electronwithdrawing carbonyl group, or coupling two vinylene carbonate structures (23)(24)(25)(26)(27)(28)(29)(30) significantly enhances the reducibility.…”

“…[9,24] Both the vertical electron affinity VEA = E(N)À E-(N + 1) and adiabatic electron affinity AEA = E(N)À E opt (N + 1) were calculated for the target structures and VC. [25][26] Meanwhile, the solvent effect was considered in calculations for better description on the redox potential in solution phase (see…”