Abstract
Due to it is potential application in the field of high energy density
materials, how to stabilize cyclopentazolate anion (cyclo-N5-) has
attracted many interests theoretically and experimentally. Therefore, a
series of ion salts containing [cyclo-N5]- were synthesized and
studied. The instability of [cyclo-N5]- is caused by the five lone
pairs of electrons localized on five neighbored N atoms. In this work,
we expect if the [cyclo-N5]- can be stabilized by the coordination
with acidic ligands, by weakening the multi repulsion from the lone
pairs to stabilize the [cyclo-N5]-. The two compounds of
[N5(BH3)5]-, and [N5(AgCN)5]- have been designed and compared
based on the Lewis acid-base theory. [N5(H2O)5]- is designed to
evaluate the effect of hydrogen bond in the stabilization. For all the
structures, we study the bonding properties and thermal stabilities
based on the analysis of electronic structures and Car-Parrinello
molecular dynamics (CPMD) simulations. The results indicate it is a
effective method to stabilize [cyclo-N5]- by introducing the Lewis
acid. Our insights on [cyclo-N5]- compounds with high thermal
stability under ambient conditions will provide a new idea for the
research and synthesis of new high energetic [cyclo-N5]- series
compounds.