CHAPTER 4: Recent Developments in Chalcogen–Nitrogen Chemistry

This chapter reviews significant advances that have been made during the past 6–7 years in the chemistry of chalcogen–nitrogen compounds from both fundamental and applied perspectives. These compounds continue to provide unique challenges for our understanding of structure and bonding in electron‐rich heterocycles. Significant progress has been made in comprehending topics such as aromaticity, weak transannular contacts, intermolecular interactions, and biradicalloid character in both well‐known and new chalcogen–nitrogen molecules. The discovery of the potential application of the classic ring‐opening polymerization of S₂N₂ to (SN)_x in forensic science (fingerprint detection) was an unforeseen development. Detailed electrochemical and photochemical studies, in conjunction with in situ EPR spectroscopy and DFT calculations, have provided insights into the pathways involved in the ring transformations that are prevalent for chalcogen–nitrogen compounds. Investigations of intermolecular interactions in selenium–nitrogen and tellurium–nitrogen compounds have attracted increasing attention because they are stronger than those observed for their sulfur analogues. In particular, C, N, Te heterocycles show promise as supramolecular building blocks for materials with unique magnetic or conducting properties.