Substituent Effect on the C-NO2 and N-NO2 Bond Dissociation Energies of Nitroaromatic Molecules

• 来源期刊: 中国化学（英文版）
• 年，卷（期）: 2008,（6）
• 页码范围: 1122-1128
• 页数: 7页
• 语种: 英文

摘要

Six density function theory methods (B3LYP,B3P86,MPWB1K1,MPWPW91,PBEPBE,TPSS1KCIS3) were used to calculate bond dissociation enthalpies of nitro compounds,where the B3P86 method was found to give the most accurate predictions.Using the B3P86 method meta-and para-substituted nitroaromatics were systematically studied for the first time.The remote substituent effects,Hammett relationships,and the origin of the substituent effects were discussed on the basis of the calculated results.Both meta-and para-substituted nitromethyl-benzenes showed significant substituent effects and a fair correlation against substituent constants (σ+p).The ground state effects were found to play the major role in determining the overall substituent effects.Meanwhile,nitroaminobenzenes showed irregular substituent effects and a poorer Hammett correlation,where both ground and radical state effects contributed to the overall substituent effects.