Viability of aromatic all-pnictogen anions

Aromaticity in novel cyclic all-pnictogen heterocyclic anions, P 2 N 3 − and P 3 N 2 − , 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, C 5 H 5 − . These singlet C 2v 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 P 3 N 2 − - a click reaction between N 2 and P 3 − , through a C 2v symmetric transition state. Besides this, the possibility of P 3 N 2 − as a η 5 -ligand in metallocenes is studied and the nature of bonding in metallocenes is discussed through the energy decomposition analysis. The structure, stability, bonding and π-aromaticity in novel cyclic all-pnictogen heterocyclic anions, P 2 N 3 − and P 3 N 2 − , and in their heavier analogues are studied using quantum mechanical computations.