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Direct Detection of a Chemical Equilibrium between a Localized Singlet Diradical and Its σ‐Bonded Species by Time‐Resolved UV/Vis and IR Spectroscopy
Author(s) -
Yoshidomi Shohei,
Mishima Megumi,
Seyama Shin,
Abe Manabu,
Fujiwara Yoshihisa,
Ishibashi Takaaki
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201612329
Subject(s) - diradical , singlet state , chemistry , photochemistry , spectroscopy , solvent , molecule , computational chemistry , chemical physics , excited state , organic chemistry , atomic physics , physics , quantum mechanics
Localized singlet diradicals are key intermediates in bond homolyses. The singlet diradicals are energetically much less stable than the σ‐bonded species. In general, only one‐way reactions from diradicals to σ‐bonded species are observed. In this study, a thermal equilibrium between a singlet 1,2‐diazacyclopentane‐3,5‐diyl diradical and the corresponding σ‐bonded species was directly observed. The singlet diradical was more stable than the σ‐bonded species. The solvent effect clarified key features, such as the zwitterionic character of the singlet diradical. The effect of the nitrogen atoms is discussed in detail.