Chia-yu Li, M. L. Caspar, D. Dixon
Sep 1, 1980
Citations
0
Influential Citations
12
Citations
Journal
Electrochimica Acta
Abstract
Abstract The electrochemical reduction of 6,11-dihydroxy-5,12-naphthacenequinone (DHNQ) in N,N - dimethylformamide was investigated. Under polarographic conditions, DHNQ behaves like a simple aromatic quinone with reduction occuring in two successive one-electron steps followed by protonation in the aprotic system and a single two-electron irreversible in the protic medium. The substituent inductive effects in several DHNQ derivatives were noted. The electron withdrawing groups, chloro and phenylsulfonyl, enhance the oxidation potentials, and the eletron-releasing groups, methyl and methoxy, make the reduction more difficult. The strength of the substituents follows the order: C 6 H 5 SO 2 ⪢ Cl ⪢ CH 3 ⪢ CH 3 O. A linear Hammett relationship exists in this series when the averaged value of σ meta and σ para are used as substitution constants.