Unusual arsenic reagent breaks periodic trend in first synthesis.

Researchers have isolated and characterised an elusive nitrene-like arsenic intermediate for the first time, revealing that heavier main group elements may have more unique chemistry than previously thought. The team used matrix isolation to extend the lifetime of the arsinidene and thoroughly characterise the individual molecules trapped within the matrix. Spectroscopic analysis revealed a C–As bond length of 1.932Å and confirmed the suspected lack of stabilising delocalisation over the phenyl substituent. The team probed the reactivity of the matrix-bound phenylarsinidene with molecular oxygen, revealing some unexpected mechanistic differences.