13012-14-1Relevant articles and documents
Aqeous and Nonaqueous Polarographic Studies of Substituted 2,6-Dimethylbenzonitrile N-Oxides1)
Kubota, Tanekazu,Hiramatsu, Sadaaki,Kano, Kenji,Uno, Bunji,Miyazaki, Hiroshi
, p. 3830 - 3839 (2007/10/02)
Aqueous and nonaqueous polarographic properties of 4-substituted 2,6-dimethylbenzonitrile N-oxides (stable nitrile N-oxides) have been studied and compared with those of the substituted pyridine N-oxides and benzylidenemethylamine N-oxides (nitrones) investigated previously by us.The first reduction wave in both the aqueous and N,N-dimethylformamide (DMF) solvent systems is due to the deoxygenation reaction of the nitrile N-oxide group except when certain substituents are present (see text).This conclusion has also been verified by controlled potential electrolysis in aqueous solution and by cyclic voltammetry in DMF solvent.A plot of the Hammett ? constants of the substituents against E1/2 values was linear with a positive slope for both the aqueous and DMF solvent systems.The slope is smaller than in the case of pyridine N-oxides and nitrones, this being reasonably attributable to the triple bond nature of the CNO group.Half-wave reduction potentials of the nitrile N-oxides are positively shifted compared with those of pyridine N-oxides, particularly in an aqueous solvent.Molecular orbital calculations were applied to interpret the substituent effect on the reduction potentials of the N-oxides. Keywords --- aqueous polarography; nonaqueous polarography; substituent effect on half-wave potential; cyclic voltammetry; controlled potential electrolysis; PPP-SCFMO; CNDO/2; LUMO energy; 4-substituted 2,6-dimethylbenzonitrile N-oxide
