83966-40-9

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• 100-11-8 p-nitrobenzyl bromide radical anion 
• 82925-36-8 Toluene-4-sulfonic acid 1-(4-nitro-phenyl)-ethyl ester 
• 5339-26-4 1-(2-Bromo-ethyl)-4-nitro-benzene 
• 19935-81-0 1-(1-Bromo-ethyl)-4-nitro-benzene 
• 19935-75-2 1-(1-Chloro-ethyl)-4-nitro-benzene 

Relevant academic research and scientific papers

Temperature Effects on Rates of Dehalogenation of Aromatic Anion Radicals

The temperature dependence of the unimolecular dehalogenation of radical anions of nitrobenzyl halides and haloacetophenones was measured between -7 and 70 deg C.Activation parameters range from Ea=11.2-16.9 kcal/mol and log A=12.7-17.1.Both Ea and log A increase from p- to o-nitro radicals and from chloro to bromo radicals.Unfavorable steric effects that move the halogen atom out of the aromatic plane result in lowered A factors.In general, the variation of k294 with structure depends in a complex way on the combination of Ea and log A factors, which suggests caution in the evaluation of rate constants at one temperature.The fast unimolecular dissociation of (p-NO2C6H4CH2Br)(1-). (k294=4.6*105 s-1) allows measurement of the slower bimolecular electron transfer (C6H5NO2)(1-).+p-NO2C6H4CH2Br->(p-NO2C6H4CH2Br)(1-).+C6H5NO2 (k294=1.9*106 M-1 s-1).Both the activation energy and probability factor contribute to the slow rate, possibly due to a geometry change upon the reduction of ArNO2.Extending the temperature studies to supercooled solutions shows no discontinuity of the unimolecular rate constants near the phase transition temperatures.

INTRAMOLECULAR ELECTRON TRANSFER AND DEHALOGENATION OF NITROAROMATIC ANION RADICALS.

A series of nitroaromatic compounds, containing Cl, Br or tosyl groups at various positions, were synthesized and studied by pulse radiolysis in aqueous alcohol solutions. One-electron reduction of the compounds produces the anion radicals which then undergo an intramolecular electron transfer and eliminate X** minus (Cl** minus , Br** minus , or TsO** minus ). The rates of X** minus elimination vary over six orders of magnitude and are affected by the C-X bond dissociation energies, the size and nature of the group bridging the X with the pi system, and the relative positions of these groups. Intramolecular electron transfer through space is also demonstrated. Refs.