Highly Electron‐Donating Antiaromatic N,N′‐Dimethyldiazaporphyrins via Reductive Dimethylation

Ni(II) N,N′‐dimethyl‐5,15‐diazaporhyrins are efficiently prepared through reductive dimethylation of 5,15‐diazaporphyrin Ni(II) complexes with sodium dispersion in the presence of dimethyl sulfate. The obtained reduced diazaporphyrins exhibit highly upfield‐shifted ¹H NMR spectra and narrowed HOMO–LUMO gaps originating from their distinct antiaromatic nature. The electrochemical analysis reveals their highly electron‐donating property, which leads to the formation of a charge transfer (CT) complex with tetracyanoquinodimethane (TCNQ) as an electron acceptor. The CT complex of Ni(II) N,N′‐dimethyl‐10,20‐diphenyl‐5,15‐diazaporphyrin with TCNQ exhibits alternate π‐stacking orientation in the solid state. N,N′‐Dimethyl‐5,15‐diazaporphyrins also interact with C₆₀ in the solid state to yield cocrystals.