Stable [48]-, [50]-, and [52]dodecaphyrins(1.1.0.1.1.0.1.1.0.1.1.0): the largest Hückel aromatic molecules

Takanori Soya; Woojae Kim; Dongho Kim; Atsuhiro Osuka

doi:10.1002/chem.201500650

Stable [48]-, [50]-, and [52]dodecaphyrins(1.1.0.1.1.0.1.1.0.1.1.0): the largest Hückel aromatic molecules

Chemistry. 2015 Jun 1;21(23):8341-6. doi: 10.1002/chem.201500650. Epub 2015 Apr 13.

Authors

Takanori Soya¹, Woojae Kim², Dongho Kim³, Atsuhiro Osuka⁴

Affiliations

¹ Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502 (Japan).
² Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 120-749 (Korea).
³ Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 120-749 (Korea). [email protected].
⁴ Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502 (Japan). [email protected].

PMID: 25866899
DOI: 10.1002/chem.201500650

Abstract

[52]Dodecaphyrin(1.1.0.1.1.0.1.1.0.1.1.0) was quantitatively oxidized with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to the corresponding [50]dodecaphyrin. Further oxidation of [50]dodecaphyrin with MnO2 quantitatively afforded [48]dodecaphyrin. Of the three, [50]dodecaphyrin showed Hückel aromatic character as the largest aromatic molecule reported to date. Protonation of [50]dodecaphyrin with methanesulfonic acid (MSA) led to the formation of a planar tetraprotonated species that displayed a sharp and intense Soret-like band at 906 nm with ε=6.5×10(5) M(-1) cm(-1) and Q-band-like bands at 1346 and 1600 nm.

Keywords: aromaticity; dodecaphyrins; expanded porphyrins; planar molecules; protonation.