We have demonstrated aromaticity reversal in the singlet excited states of internally 1,3-phenylene-strapped - and hexaphyrins (P26H and P28H). P26H displays a broad and reduced singlet-excited-state absorption spectrum, whereas P28H exhibits a sharp and intense singlet-excited-state absorption spectrum; both are in contrast to the ground-state absorption spectra, strongly indicating aromaticity reversal in the singlet excited state. Furthermore, magnetic and topological indices of aromaticity such as nucleus-independent chemical shift and harmonic oscillator model of aromaticity values for P26H and P28H also suggest that their singlet excited states become antiaromatic and aromatic, respectively.
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© 2015 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry