Simulating the Pyrolysis of Polyazides: a Mechanistic Case Study of the [P(N₃)₆]⁻ Anion

Abstract

Pyrolysis of the homoleptic azido complex [P­(N₃)₆]⁻ was simulated using density functional theory based molecular dynamics and analyzed further using electronic-structure calculations in atom-centered basis sets to calculate the geometries and electronic structures. Simulations at 600 and 1200 K predict a thermally induced and, on the simulation time scale, irreversible dissociation of an azido anion. The ligand loss is accompanied by a barrierless (free-energy) transition of the geometry of the complex coordination sphere from octahedral to trigonal bipyramidal. [P­(N₃)₅] is fluxional and engages in pseudorotation via a Berry mechanism