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On the Homoconjugation of Two Acceptor Groups
Author(s) -
Doerner Thomas,
Gleiter Rolf,
Neugebauer Franz A.
Publication year - 1998
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199808)1998:8<1615::aid-ejoc1615>3.0.co;2-n
Subject(s) - chemistry , phenazine , quinoxaline , acceptor , electron acceptor , stereochemistry , unpaired electron , bicyclic molecule , crystallography , photochemistry , radical , organic chemistry , physics , condensed matter physics
Cyclovoltammetric investigations have been carried out on 3,3,6,6‐tetramethylcyclohexane‐1,2,4,5‐tetrone ( 4 ), bicyclo‐[3.2.2]nonane‐6,7,8,9‐tetrone ( 5 ), and several of their congeners, such as 6,13‐dihydro‐6,6,13,13‐tetramethylquin‐oxalino[2.3‐ b ]phenazine ( 13 ), 5,10‐dihydro‐5,5,10,10‐tetra‐methylpyrazino[2,3‐ g ]quinoxaline ( 17 ), and 6,13‐dihydro‐6,13‐propanoquinoxalino[2,3‐ b ]phenazine ( 20 ). For 5 and 20 a large difference (Δ E ° ≥400 mV) between the first and second reduction potentials was found. The ESR results of the radical anion 20 •– are in support of a strong homoconjugation. ESR studies of 4 •– , 13 •– , and 17 •– also reveal a symmetrical displacement of the unpaired electron over both acceptor groups on the ESR time scale which, however, based on the small potential difference Δ E ° ≤ 200 mV can be most likely described to a fast electron exchange.