Monocoordinated nitrenes and heavier pnictinidenes: transient to bottleable compounds

Nitrenes (N-R) and heavier pnictinidenes (Pn-R; Pn = P-Bi, R = anionic substituents), which are monovalent group 15 elements, have long been regarded as fleeting reactive intermediates in organic chemistry, with their existence typically confirmed only under matrix isolation conditions. The past few years have witnessed a striking evolution of these species from ephemeral curiosities into isolable, well-defined compounds under ambient laboratory conditions, irrespective of their singlet or triplet ground states. This perspective provides a chronological review of recent advances in the counterintuitive chemistry of nitrenes and pnictinidenes in the condensed phase, including their diverse synthetic methodologies and unusual bonding and structural features.