ORGN 80 |
| We have been trying to develop electrocatalysts exhibiting highly positive oxidation potentials. Steckhan and coworkers synthesized a series of polybromotriphenylamines and found that the oxidation potential of these substances increase with increasing degree of bromine substitution. Since the Hammett substituent effect of the 4-nitro group is considerably higher than that of bromine, trinitrotriphenylamine and derivatives of it containing bromine should have higher oxidation potentials and so could be attractive electrocatalysts. We report here the nitration of triphenylamine, tris(4-bromophenyl)amine(1) and other triphenylamines substituted at the para positions. Besides polynitration products, nitrodebromination products were also obtained from nitration of 1 under mild reaction conditions [Cu(NO3)2/Ac2O/0~25 °C]. Mechanisms are proposed to rationalize the results. The ionization potentials of several substituted triarylamines were computed by density functional theory (B3LYP/6-31G*) and the oxidation potentials were measured by cyclic voltammetry as well. Some substituted triarylamines are computed to have different geometries from the parent triphenylamine. |
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Physical Organic Chemistry: Calculations, Mechanisms, Photochemistry, and High-Energy Species
1:00 PM-5:20 PM, Sunday, 10 September 2006 Moscone Center -- Room 133, Oral
Division of Organic Chemistry |