Homoleptic complexes of isocyano- and diisocyanobiazulenes with a 12-electron, ligand-based redox capacity.

Oligo- and polyazulenes are attractive π-conjugated building blocks in designing advanced functional materials. Herein, we demonstrate that anchoring one or both isocyanide termini of the redox non-innocent 2,2'-diisocyano-6,6'-biazulenic π-linker (1) to the redox-active [Cr(CO)] moiety provided a convenient intramolecular redox reference for unambiguously establishing that the 6,6'-biazulenic scaffold undergoes a reversible one-step 2 reduction governed by reduction potential compression/inversion. Treatment of bis(η-naphthalene)chromium(0) with six equiv.