Showing papers on "DPPH published in 1974"

The Reaction of Diphenylpicrylhydrazyl with Physiological Compounds

Abstract: The reaction of the stable free radical diphenylpicrylhydrazyl (DPPH) with catecholic metabolites and other physiological compounds is described DPPH reacts in high molar ratios with dihydroxyphenylalanine, homovanillic acid, vanilmandelic acid, dihydroxyphenethylamine, and related metabolites, and offers A new colorimetric test for these compounds

Notizen: E-Radiation Induced Nitration of DPPH by NO2 Radicals

Abstract: The radiation chemistry of simple nitro-alkanes has been investigated principally in the vapour phase2, bu t also in the liquid phase3; in all cases, the prim ary process is considered to be a homolytic cleavage of the carbon-nitrogen bond. ESR evi­ dence for an alternative pathw ay in solution in ­ volving intermolecular hydrogen abstraction and the form ation of the radical R N 0 2H has recently been advanced4. Our studies of the e-radiation chem istry of dilute solutions of D PPH in nitrogen dioxide containing solvents such as nitrom ethane, nitrobenzene, and 95 atom % 15N enriched n itro ­ benzene have revealed details which might shed some light on the chemical mechanisms of radiation induced n itra tion of the phenyl ring in D PPH . Both reactions provide convincing chemical evi­ dence for C-N bond cleavage and for hydrogen abstraction. p-Nitro dipheny Ipi cry lhy drazine (N 0 2-D P P H 2) and diphenylpicrylhydrazine (D PPH 2) have been previously identified as major products of D PPH radiolysis in m ethyl iodide solution1 and their presence has been confirmed in the present work. The 100 eV yields (G-values) of the different reaction products are given in Table I. For all runs a s tand ­ ard dose of 1 ■ 1021 eV g-1 was used.