Stabilizing Doubly Deprotonated Diazomethane: Isolable Complexes with CN<sub>2</sub><sup>2–</sup> and CN<sub>2</sub><sup>–</sup> Radical Ligands
Ze‐Jie Lv, Philipp D. Engel, Lukas Alig, Sandipan Maji, Max C. Holthausen, Sven Schneider
Abstract
Transition metal complexes with a doubly deprotonated diazomethane (CNN2–) ligand have been proposed as fleeting intermediates in nitrogen transfer reactions. However, in contrast to isoelectronic azide (N3–), well-defined examples are unknown. We here report the synthesis and characterization of isolable complexes with terminal and bridging CNN2– ligands, stabilized by platinum(II) pincer fragments. Bonding within the allenic dimetallanitrilimine core (Pt–N═N═C–Pt) was probed by oxidation of the bridging ligand. Enhanced reactivity toward [3 + 2]-cycloaddition with CO2 was obtained. Photofragmentation favors N–NC over NN–C bond cleavage as a route to cyanide and a transient metallonitrene complex.