Pratt, Derek A. published the artcileSubstituent Effects on the Bond Dissociation Enthalpies of Aromatic Amines, Recommanded Product: Bis(4-nitrophenyl)amine, the publication is Journal of the American Chemical Society (2002), 124(37), 11085-11092, database is CAplus and MEDLINE.
Bond dissociation enthalpy differences, Z-X ¦¤BDE = BDE(4-YC6H4Z-X) – BDE(C6H5Z-X), for Z = CH2 and O are largely independent of X and are determined mainly by the stabilization/destabilization effect of Y on the 4-YC6H4Z? radicals. The effects of Y are small (¡Ü2 kcal/mol for all Y) for Z = CH2, but they are large for Z = O, where good correlations with ¦Òp+(Y) yield ¦Ñ+ = 6.5 kcal/mol. For Z = NH, two sets of electrochem. measured N-H ¦¤BDEs correlate with ¦Òp+(Y), yielding ¦Ñ+ = 3.9 and 3.0 kcal/mol. However, in contrast to the situation with phenols, these data indicate that the strengthening effect on N-H BDEs of electron-withdrawing (EW) Y’s is greater than the weakening effect of electron-donating (ED) Y’s. Attempts to measure N-H ¦¤BDEs in anilines using two nonelectrochem. techniques were unsuccessful; therefore, we turned to d. functional theory. Calculations on 15 4-YC6H4NH2 gave N-H ¦¤BDEs correlating with ¦Òp+ (¦Ñ+ = 4.6 kcal/mol) and indicated that EW and ED Y’s had comparable strengthening and weakening effects, resp., on the N-H bonds. To validate theory by connecting it to experiment, the N-H ¦¤BDEs of four 4,4′-disubstituted diphenylamines and five 3,7-disubstituted phenothiazines were both calculated and measured by the radical equilibration EPR technique. For all compounds, theory and experiment agreed to better than 1 kcal/mol. Dissection of N-H ¦¤BDEs in 4-substituted anilines and O-H ¦¤BDEs in 4-substituted phenols into interaction enthalpies between Y and NH2/OH (mol. stabilization/destabilization enthalpy, MSE) and NH?/O? (radical stabilization/destabilization enthalpy, RSE) reveals that for both groups of compounds, ED Y’s destabilize the mol. and stabilize the radical, while the opposite holds true for EW Y’s. However, in the phenols the effects of substituents on the radical are roughly 3 times as great as those in the mol., whereas in the anilines the two effects are of comparable magnitudes. These differences arise from the stronger ED character of NH2 vs OH and the weaker EW character of NH? vs O?. The relatively large contributions to N-H BDEs in anilines arising from interactions in the mols. suggested that N-X ¦¤BDEs in 4-YC6H4NH-X would depend on X, in contrast to the lack of effect of X on O-X and CH2-X ¦¤BDEs in 4-YC6H4O-X and 4-YC6H4CH2-X. This suggestion was confirmed for X = CH3, H, OH, and F, for which the calculated NH-X ¦¤BDEs yielded ¦Ñ+ = 5.0, 4.6, 4.0, and 3.0 kcal/mol, resp.
Journal of the American Chemical Society published new progress about 1821-27-8. 1821-27-8 belongs to catalysis-chemistry, auxiliary class Nitro Compound,Amine,Benzene, name is Bis(4-nitrophenyl)amine, and the molecular formula is C12H9N3O4, Recommanded Product: Bis(4-nitrophenyl)amine.
Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia