36877-84-6Relevant academic research and scientific papers
Kinetic study of the hydrogen abstraction reaction of the benzotriazole-N-oxyl radical (BTNO) with H-donor substrates
Brandi, Paolo,Galli, Carlo,Gentili, Patrizia
, p. 9521 - 9528 (2007/10/03)
The aminoxyl radical (>N-O.) BTNO (benzotriazole-N-oxyl) has been generated by the oxidation of 1-hydroxybenzotriazole (HBT; >N-OH) with a CeIV salt in MeCN. BTNO presents a broad absorption band with λmax 474 nm and e 184
Lifetimes and UV-visible absorption spectra of benzyl, phenethyl, and cumyl carbocations and corresponding vinyl cations. A laser flash photolysis study
Cozens, Frances L.,Kanagasabapathy,McClelland, Robert A.,Steenken, Steen
, p. 2069 - 2082 (2007/10/03)
Benzyl (4-MeO, 4-Me, and 4-methoxy-1-naphthylmethyl), phenethyl (4- Me2N, 4-MeO, 3,4-(MeO)2, 4-Me, 3-Me, 4-F, 3-MeO, 2,6-Me2, parent, and 4- methoxy-1-naphthylethyl) and cumyl (4-Me2N, 4-MeO, 4-Me, parent) cations have been studied by laser flash photolysis (LFP) in 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoroisopropanol (HFIP). In most cases styrene or α-methylstyrene precursors were employed for the phenethyl and cumyl ions, the intermediate being obtained by solvent protonation of the excited state. Benzyl cations were generated by photoheterolysis of trimethylammonium and chloride precursors. While a 4-MeO substituent provides sufficient stabilization to permit observation of cations in TFE, cations with less stabilizing substituents usually require the less nucleophilic HFIP. Even in this solvent, the parent benzyl cation is too short-lived (lifetime 6H4C+(R)-CH3 (R = Me, Et, i-Pr, t-Bu, cyclopropyl, C6H5, 4-MeOC6H4) were generated in TFE via the photoprotonation route. The alkyl series shows that steric effects are important in the decay reaction. The cation with R = cyclopropyl is a factor of 1.5 less reactive than the cation where R = phenyl. Several vinyl cations have also been generated by photoprotonation of phenylacetylenes. ArC+=CH2 has a reactivity very similar to that of its analog ArC+H-CH3, the vinyl cation being slightly (factors of 2-5) shorter-lived. For the various series of cations, including vinyl, substituents in the aryl ring have a consistent effect on the κ(max), a shift to higher wavelength relative to hydrogen of 15 nm for 4-Me, 30 nm for 4-MeO, and 50 nm for 4-Me2N.
Proton-transfer reactions of alkylaromatic cation radicals. The effect of α-substituents on the kinetic acidity of p-methoxytoluene cation radicals
Baciocchi,Del Giacco,Elisei
, p. 12290 - 12295 (2007/10/02)
The rates of deprotonation for a number of α-substituted p- methoxytoluene cation radicals (4-MeOPhCH2X·+ with X = H, Me, OAc, OH, OMe, Cl, CN, Ph, 4-MeOPh, and 4-MeOPhCD3·+) have been determined by a laser phot
