Osamu IWANAGA

<jats:p>New μ-OH-μ-O<jats:sub>2</jats:sub>-Co(<jats:sc>iii</jats:sc>)<jats:sub>2</jats:sub> complexes with 6-hpa ligand were synthesized and structurally characterized. The 6-hpa ligand facilitates O–O bond formation to enhance the catalytic activity in O<jats:sub>2</jats:sub> evolution <jats:italic>via</jats:italic> electrochemical water oxidation.</jats:p>

Abstract meso‐Unsubstituted (meso‐free) porphyrins have been an effective platform for creating versatile peripherally functionalized porphyrins and directly‐linked porphyrin oligomers. The synthetic strategy has been extended to produce meso‐free porphyrinoids including carbaporphyrins, core‐modified porphyrins, ring‐contracted, and ring‐expanded porphyrins. meso‐Free porphyrinoids can serve as a benchmark for demonstrating the inherent physical properties and stabilities, free from the influences of substituents, thereby highlighting the significance of these porphyrinoid classes.

Abstract The free base form of doubly meso‐α linked N‐confused porphyrin (NCP) tape 3 was successfully synthesized via Ir(I) mediated intramolecular coupling. The following silver complexation afforded the Ag(III) complex of doubly meso‐α linked NCP tape 4. While 3 exhibited 38π aromatic characters, 4 exhibited not only 18π aromatic NCP‐type characteristics but also a decent antiaromatic contribution of 12π pyrrolo[2,3‐f]indole segment, as probed by NMR spectra, absorption spectra, and DFT calculations.