Electron-transfer reactions. IX. Formation of azo radical anions and their vinylogs

Experimental and Computational Studies of Structure and Bonding in Parent and Reduced Forms of the Azo Dye Orange II

“…The splittings obtained here suggest that the electron spin densities on the nitrogen atoms in the protonated radical anion of Orange II in water are lower than the equivalent values for these other dyes in ethanol. EPR studies of the reduction of azobenzene 76,77 and substituted azobenzenes 78 in DMSO reported two identical nitrogen splittings of a N ) 4.7-5.0 G, similar to the larger of the two nitrogen splittings determined here for Orange II; however, it is unlikely that these reduced azobenzene species were protonated under the reported conditions.…”

“…There have been relatively few reported EPR studies of azo species, ,,− particularly of azo dyes. , One previous EPR study of the reduction of several sulfonated 2-(naphthylazo)-1-naphthol dyes in ethanol 50 gave spectra that were simulated by two nitrogen splittings in the range of a N = 7.4−7.9 and 4.5−5.7 G, three proton splittings of a H = 4.7−5.8, 4.1−4.8, and 1.1−2.0 G, and g = 2.0038 for each dye; the observed spectra were assigned to protonated hydrazyl radical anions, as assigned here for Orange II. The splittings obtained here suggest that the electron spin densities on the nitrogen atoms in the protonated radical anion of Orange II in water are lower than the equivalent values for these other dyes in ethanol.…”

Facile, Completely Regioselective 1,4-Hydrogenations of C60-Diaryltetrazine Monoadducts

“…Dihydrotetrazines are well-known organic electron donors . Electron transfer from 6 to 2 must require initial photoexcitation of 2 since 2 is not converted to (±)- 3 in the dark but under otherwise identical conditions.…”

Synthesis of a novel photoresponsive axially chiral phosphine ligand containing an arylazo group and its application to palladium‐catalyzed asymmetric allylic alkylation

“…The AZOPs (S)-1a and 1b were obtained through a condensation reaction of aminophosphine (S)-2 with appropriate nitrosobenzenes under basic conditions (Scheme 1). 10 A conventional acidic condition using AcOH was found to be less effective for this dehydrative N=N bond-forming reaction. 11 An attempted reaction of (S)-2 with 2-or 4-methylnitrosobenzene did not proceed, presumably due to the poor electrophilicity of the nitroso compounds.…”