Protonation-Triggered Hückel and Möbius Aromatic Transformations in Nonaromatic Core-Modified [30]Hexaphyrin(2.1.1.2.1.1) and Annulated [28]Hexaphyrin(2.1.1.0.1.1)

Syamasrit Dash; Arindam Ghosh; A Srinivasan; Cherumuttathu H Suresh; Tavarekere K Chandrashekar

doi:10.1021/acs.orglett.9b03805

Protonation-Triggered Hückel and Möbius Aromatic Transformations in Nonaromatic Core-Modified [30]Hexaphyrin(2.1.1.2.1.1) and Annulated [28]Hexaphyrin(2.1.1.0.1.1)

Org Lett. 2019 Dec 6;21(23):9637-9641. doi: 10.1021/acs.orglett.9b03805. Epub 2019 Nov 25.

Authors

Syamasrit Dash¹, Arindam Ghosh¹, A Srinivasan¹, Cherumuttathu H Suresh², Tavarekere K Chandrashekar¹

Affiliations

¹ School of Chemical Sciences , National Institute of Science Education and Research (NISER) Bhubaneswar 752050 , Odisha, HBNI , India.
² Inorganic and theoretical chemistry section, Chemical Science and Technology Division , CSIR-National Institute of Interdisciplinary Science and Technology , Trivandrum 695019 , Kerala , India.

PMID: 31763854
DOI: 10.1021/acs.orglett.9b03805

Abstract

Two 1,2-diphenyl-1,2-dithienylethene-embedded hexaphyrins 6 and 8 containing 30π and 28π electrons, respectively, in conjugation exhibit nonaromatic characteristics. Compound 6 shows an unusual bond length equalization in its electronic structure. However, on protonation, 6 exhibits Hückel aromatic characteristics while 8 shows Möbius aromatic characteristics. The changes in aromaticity are accompanied by change in conformation from a figure-eight/twisted structure to an open extended structure.