A Description of Vibrational Modes in Hexaphyrins: Understanding the Aromaticity Reversal in the Lowest Triplet State

Young Mo Sung, Juwon Oh, Koji Naoda, Taegon Lee, Woojae Kim, Manho Lim, Atsuhiro Osuka, Dongho Kim

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Aromaticity reversal in the lowest triplet state, or Baird's rule, has been postulated for the past few decades. Despite numerous theoretical works on aromaticity reversal, experimental study is still at a rudimentary stage. Herein, we investigate the aromaticity reversal in the lowest excited triplet state using a comparable set of [26]- and [28]hexaphyrins by femtosecond time-resolved infrared (IR) spectroscopy. Compared to the relatively simple IR spectra of [26]bis(rhodium) hexaphyrin (R26H), those of [28]bis(rhodium) hexaphyrin (R28H) show complex IR spectra the region for the stretching modes of conjugated rings. Whereas time-resolved IR spectra of R26H in the excited triplet state are dominated by excited state IR absorption peaks, while those of R28H largely show ground state IR bleaching peaks, reflecting the aromaticity reversal in the lowest triplet state. These contrasting IR spectral features serve as new experimental aromaticity indices for Baird's rule.

Original languageEnglish
Pages (from-to)11930-11934
Number of pages5
JournalAngewandte Chemie - International Edition
Volume55
Issue number39
DOIs
Publication statusPublished - 2016 Sep 19

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Infrared radiation
Excited states
Rhodium
Infrared absorption
Bleaching
Ground state
Stretching
Infrared spectroscopy

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

Cite this

Sung, Young Mo ; Oh, Juwon ; Naoda, Koji ; Lee, Taegon ; Kim, Woojae ; Lim, Manho ; Osuka, Atsuhiro ; Kim, Dongho. / A Description of Vibrational Modes in Hexaphyrins : Understanding the Aromaticity Reversal in the Lowest Triplet State. In: Angewandte Chemie - International Edition. 2016 ; Vol. 55, No. 39. pp. 11930-11934.
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A Description of Vibrational Modes in Hexaphyrins : Understanding the Aromaticity Reversal in the Lowest Triplet State. / Sung, Young Mo; Oh, Juwon; Naoda, Koji; Lee, Taegon; Kim, Woojae; Lim, Manho; Osuka, Atsuhiro; Kim, Dongho.

In: Angewandte Chemie - International Edition, Vol. 55, No. 39, 19.09.2016, p. 11930-11934.

Research output: Contribution to journalArticle

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