Crystalline nitrogen chain radical anions
摘要
Long-chain nitrogen ions and radicals ([Nn]x+/[Nn]x−, n > 3) are naturally occurring under the intense radiative conditions of the Earth’s ionosphere and those of other planetary bodies. However, the strong thermodynamic driving force to lose N2 renders these types of molecule extremely reactive under ambient conditions such that they can typically be studied only under extreme conditions, for example, at ultrahigh pressures (10 GPa to >200 GPa). Here we report the isolation of a series of five molecules featuring metal unsupported {N4}•− units under ambient conditions, with one derivative demonstrating remarkable multi-week long persistence in the solid state. Spectroscopic, crystallographic and computational studies provide insight into the bonding across the {N4}•− chain. Reactivity studies reveal that the chain can cleave into N1 and N3 fragments, and can act as a source of nitrene radical anions, an observation that such molecules could act as storable nitrogen group transfer reagents.