Tetraphenylhydrazine temperature

Figure Bl.16.18. TREPR spectra observed after laser excitation of tetraphenylhydrazine in an SDS micelle at room temperature. Reprinted from [61].

Experiments—Dissolve about 0-5 g. of tetraphenylhydrazine in 5 c.c. of xylene and warm the solution slowly over a small flame. The initially colourless solution becomes intensely olive green, even before the boiling point of the solvent is reached. The colour is that of the free radicle which, at this temperature, very rapidly under-1 Cf. F. Sachs, Ber., 1901, 34, 497. 

Diphenylamine is only slowly converted even at higher temperatures (50% water 50% t-butanol, O.IM KOH, 50 °C) and there it yields thermal decomposition products, that possibly originate from tetraphenylhydrazine . ... 

Kavun and Buchachenko (247) have found that the "primary" amino radicals derived from thioamines in the presence of hydroperoxide are very stable and are not readily converted into "secondary" nitroxide radicals. Kommandeur and Wiersma (107) studied the photodecomposition of tetraphenylhydrazine in rigid solution at 77°K, and the observed ESR spectrum was assigned to the dimer of the diphenyl amino radical (248). Shida et al. (249) have also studied the photodimer of tetraphenylhydrazine and the photochromic dimer of triphenylimidazolyl at low temperature by optical and ESR techniques. These authors noted that photolysis of these compounds induces the homolysis while y-irradiation leads to heterolytic dissociation. Blinder et al. (250) reported the ESR spectrum of the monomer tetraphenylpyrryl radical in... 

The photolysis of tetraphenylhydrazine (I), triphenylhydrazine (II) and sym-diphenylhydrazine (III) at 3150 A at liquid nitrogen temperature was examined qualitatively in epa . The progress of the photolysis was followed both optically by spectrophotometry and also with esr which detected the PHjN- radical in a steady state concentration. The photolysis of (I) and (II) leads to photofission of the N-N bond, and in the latter case PhjN and PhNH- are detected. The reaction of (III) appears to be different and also to involve some photooxidation or photoionization. 

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