Facile Redox‐Induced Aromatic–Antiaromatic Interconversion of a β‐Tetracyano‐21, 23‐Dithiaporphyrin under Ambient Conditions. Issue 16 (3rd March 2020)

• Record Type: Journal Article
• Authors: Yamashita, Ken‐ichi; Nakajima, Kana; Honda, Yusuke; Ogawa, Takuji
• Is Part Of: Chemistry. Volume 26:Issue 16(2020)
• Page Start: 3633
• Page End: 3640
• Publication Date: 2020-03-03
• Subjects: antiaromaticity -- aromaticity -- isophlorins -- porphyrinoids -- redox chemistry; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201905823
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Facile redox‐induced aromatic–antiaromatic interconversions were accomplished by using β‐tetracyano‐21, 23‐dithiaporphyrin (CN4 S2 Por). Introduced cyano groups not only increased the reduction potential of the porphyrin core but also stabilized the antiaromatic isophlorin (CN4 S2 Iph) by π conjugation. The reduction of CN4 S2 Por with hydrazine in polar solvents quantitatively affords CN4 S2 Iph, even under ambient conditions. CN4 S2 Iph retains a nearly planar conformation and exhibits considerable antiaromaticity. Aerobic oxidation of CN4 S2 Iph to CN4 S2 Por occurs in nonpolar solvents. This study was conducted to contribute to the understanding of the structure–antiaromaticity relationship. Abstract : Facile redox‐induced aromatic–antiaromatic interconversion was accomplished with β‐tetracyano‐21, 23‐dithiaporphyrin. The introduced cyano groups not only increased the reduction potentials of the porphyrin core, but also stabilized the antiaromatic state of isophlorin by conjugation.