2025/09/03 by Hosahalli S. Udaya, Venkataramanarao G. Anand · 1 voice
Materials Science · Chemistry · Biochemistry, Genetics and Molecular Biology · #Porphyrin and Phthalocyanine Chemistry #Metal-Catalyzed Oxygenation Mechanisms #Photosynthetic Processes and Mechanisms
paper · doi:10.1021/acs.orglett.5c02924
openalex publication_date 2025/09/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/13
Unlike aromatic porphyrins, conventional oxidative coupling reactions do not yield dimeric or oligomeric antiaromatic porphyrinoids. We describe here the first example of a β–β-linked antiaromatic expanded porphyrinoid through a novel synthetic strategy. It contains two 24π sapphyrin units, which undergo independent reversible two-electron oxidation to yield the aromatic tetracation. The neutral and oxidized states have both been validated by electronic absorption spectroscopy, mass spectrometry, and spectro-electrochemical studies. 1 H NMR spectroscopy and quantum chemical calculations substantiated the contrasting ring current effect for both the parent 24π sapphyrin and its β–β dimer in their neutral and oxidized states. Single-crystal X-ray diffraction studies confirmed the planar conformation for the parent 24π sapphyrin, its 22π dication, and the neutral β–β-linked dimer.