Generation of the NCN Radical from Co‐Conversion of N ₂ and CO ₂ Mediated by the Niobium Oxide Cluster Anion Nb ₂ O ₃ ^–

Abstract

Abstract Cyanonitrene radical (NCN) is a valuable species involved in many subareas of chemistry including combustion, atmospheric, interstellar, and synthetic chemistry. However, the generation of NCN via C─N coupling from the abundantly available molecules N 2 and CO 2 remains a significant challenge due to the inertness of their chemical bonds and competing side reactions. In this study, by using state‐of‐the‐art mass spectrometry and quantum chemistry calculations, the niobium oxide cluster anion Nb 2 O 3 – is shown to enable the co‐conversion of N 2 and CO 2 at room temperature, achieving the formation of two C─N bonds and the generation of a free NCN radical upon external energy input. The prior complete dissociation of N 2 on Nb 2 O 3 – was found to generate two bridgingly bonded nitrogen atoms (N b ), together with adjacent metal centers, which function as Lewis acid−base pairs (Nb δ+ ─N δ– ) to activate CO 2 , leading to the spontaneous formation of the first C─N bond. The nitrogen‐centered radicals and dinuclear metal (Nb) centers play pivotal roles in promoting the formation of the second C─N bond and in facilitating the removal of two oxygen atoms from CO 2 , culminating in the generation of NCN. This study introduces a novel route for NCN radical generation through the unprecedented co‐conversion of N 2 and CO 2 .