Post Synthetic Conversion of a Cross‐Conjugated Doubly N‐Confused Porphyrinoid to the (Anti) Aromatic Analogues and an Organopalladium(IV) Complex

ABSTRACT

Controlled oxidation strategy has enabled the clean transformation of a cross‐conjugated doubly N‐confused porphyrinoid into two hitherto unknown fully (anti)aromatic analogues. Oxidation with chloranil selectively installs carbonyl functionality at the N‐confused pyrrole unit, generating an 18π aromatic macrocycle ( 8 ) that is stable in the free‐base state and structurally authenticated by x‐ray diffraction, while DDQ oxidized tri‐oxo analogue 9 is antiaromatic. The restored π‐conjugation of 8 not only produces characteristic vis–NIR absorption features but also renders the macrocycle competent to stabilize a formally square‐planar Pd(IV) center, affording the organometallic complex 10 in high yield. Porphyrinoid 9 remained unsusceptible to Pd metallation. Detailed spectroscopic characterization, supported by DFT calculations, confirms excellent agreement between experimental and computed structural, electronic, and optical properties. The conversion from a cross‐conjugated porphyrin to an aromatic framework, and its subsequent metalation, demonstrates a robust approach for accessing new N‐confused porphyrinoid architectures with tunable π ‐aromaticity.