화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.137, No.37, 11856-11859, 2015
Switching between Aromatic and Antiaromatic 1,3-Phenylene-Strapped [26]-and [28]Hexaphyrins upon Passage to the Singlet Excited State
We have demonstrated aromaticity reversal in the singlet excited states of internally 1,3-phenylene-strapped [26]- and [28]hexaphyrins (P26H and P2811). 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.