Viability of aromatic all-pnictogen anions

Abstract

Aromaticity in novel cyclic all-pnictogen heterocyclic anions, P2N3− and P3N2−, and in their heavier analogues is studied using quantum mechanical computations. All geometrical parameters from optimized geometry, bonding, electron density analysis from quantum theory of atoms in molecules, nucleus-independent chemical shift, and ring current density plots support their aromaticity. The aromatic nature of these molecules closely resembles that of the prototypical aromatic anion, C5H5−. These singlet C2v symmetric molecules are comprised of five distinct canonical structures and are stable up to at least 1000 fs without any significant distortion. Mechanistic study revealed a plausible synthetic pathway for P3N2− – a click reaction between N2 and P3−, through a C2v symmetric transition state. Besides this, the possibility of P3N2− as a η5-ligand in metallocenes is studied and the nature of bonding in metallocenes is discussed through the energy decomposition analysis.