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Preparation and Properties of a Polycyclic p ‐Quinodimethane with Two Oxygen Bridges and its Radical Cation in Comparison with the Isomeric o ‐Quinodimethane
Author(s) -
Sato Chihiro,
Suzuki Shuichi,
Okada Keiji,
Kozaki Masatoshi
Publication year - 2018
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201801269
Subject(s) - chemistry , radical ion , absorption (acoustics) , redox , oxygen , salt (chemistry) , ring (chemistry) , absorption spectroscopy , photochemistry , infrared spectroscopy , crystallography , inorganic chemistry , ion , materials science , organic chemistry , physics , quantum mechanics , composite material
We prepared an electron‐rich p ‐quinodimethane compound, 2,9‐dibromo‐7,14‐dimesityl‐5,12‐dioxapentacene ( 1 ). The quinoidal character was clarified by bond‐length alternation in the central ring. Clear vibrational structures in both absorption and emission bands and small Stokes shift indicate the rigid dioxapentacene framework. The reversible redox waves of 1 were observed at +0.14 and +0.69 V vs. Fc + /Fc, respectively. The radical cation salt 1 ⋅+ ⋅SbF 6 − was successfully isolated and characterized by means of X‐ray structural analysis and ESR and UV/Vis‐near infrared absorption spectroscopies. The molecular structure and electronic properties of the neutral and radical cation species were compared to those of the isomeric o ‐quinodimethane.