Stabilizing Doubly Deprotonated Diazomethane: Isolable Complexes with CN22- and CN2- Radical Ligands

Ze-Jie Lv; Philipp D Engel; Lukas Alig; Sandipan Maji; Max C Holthausen; Sven Schneider

doi:10.1021/jacs.2c10743

Stabilizing Doubly Deprotonated Diazomethane: Isolable Complexes with CN₂^2- and CN₂^- Radical Ligands

J Am Chem Soc. 2022 Dec 7;144(48):21872-21877. doi: 10.1021/jacs.2c10743. Epub 2022 Nov 21.

Authors

Ze-Jie Lv¹, Philipp D Engel², Lukas Alig¹, Sandipan Maji¹, Max C Holthausen², Sven Schneider¹

Affiliations

¹ Institut für Anorganische Chemie, University of Göttingen, Tammannstraße 4, 37077 Göttingen, Germany.
² Institut für Anorganische und Analytische Chemie, Goethe-Universität, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main, Germany.

PMID: 36410000
DOI: 10.1021/jacs.2c10743

Abstract

Transition metal complexes with a doubly deprotonated diazomethane (CNN^2-) 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 CNN^2- 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.