Energetics of Baird aromaticity supported by inversion of photoexcited chiral [4n]annulene derivatives.

ABSTRACT: For the concept of aromaticity, energetic quantification is crucial. However, this has been elusive for excited-state (Baird) aromaticity. Here we report our serendipitous discovery of two nonplanar thiophene-fused chiral [4n]annulenes ^Th4 COT _Saddle and ^Th6 CDH _Screw , which by computational analysis turned out to be a pair of molecules suitable for energetic quantification of Baird aromaticity. Their enantiomers were separable chromatographically but racemized thermally, enabling investigation of the ring inversion kinetics. In contrast to ^Th6 CDH _Screw , which inverts through a nonplanar transition state, the inversion of ^Th4 COT _Saddle , progressing through a planar transition state, was remarkably

SUBMITTER: Ueda M 

PROVIDER: S-EPMC5570949 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature