EPR Spectroscopy of Radical Ions of a 2,3-Diamino-1,4-naphthoquinone Derivative

0490380 - ÚOCHB 2019 RIV US eng J - Journal Article
Tarábek, Ján - Wen, Jin - Dron, P. I. - Pospíšil, Lubomír - Michl, Josef
EPR Spectroscopy of Radical Ions of a 2,3-Diamino-1,4-naphthoquinone Derivative.
Journal of Organic Chemistry. Roč. 83, č. 10 (2018), s. 5474-5479. ISSN 0022-3263. E-ISSN 1520-6904
R&D Projects: GA ČR GA15-19143S
Institutional support: RVO:61388963
Keywords : singlet fission * energies * model
OECD category: Organic chemistry
Impact factor: 4.745, year: 2018

We report the electron paramagnetic resonance spectra of the radical cation and radical anion of 1,2,2,3-tetramethy1-2,3-dihydro-1H-naphtho-[2,3-d]-imidazole-4,9-dione (1) and its doubly C-13 labeled analogue 2, of interest for singlet fission. The hyperfine coupling constants are in excellent agreement with density functional theory calculations and establish the structures beyond doubt. Unlike the radical cation 1(.+), the radical anion 1(.-) and its parent 1 have pyramidalized nitrogen atoms and inequivalent methyl groups 15 and 16, in agreement with the calculations. The distinction is particularly clear with the labeled analogue 2(.-).
Permanent Link: http://hdl.handle.net/11104/0284626