【摘要】 应用密度泛函理论对腙的硝化产物C′-硝基-对-甲氧基苯甲醛-2,4-二硝基苯腙(P)的4种构型进行了研究．发现在4种构型中π键均有离域,能量由低到高的顺序为P1<P2-P3<P4．P1中存在分子内三中心氢键,该分子内三中心氢键影响HOMO-3轨道．用AM1方法计算的结果表明P2易转化成P1,P4易转化成P3,主要产物应是P1和P3．在有质子存在时,P3转化成P1的能量为37．2 kJ／mol,得到热力学平衡产物P1和P3,并用1HNMR从实验上得到了一致的结果．更多还原

【Abstract】 A theoretical investigation into four conformations of C’-nitro-p-methoxy-benzaldehyde-2, 4-dinitro-phenylhydrazone(P) is undertaken at the Density Functional Theory level. Computational results show that:πelectrons are delocalized in all the four conformations, whose energy sequence is P1< P2 -P3 < P4 and the intramolecular three-center hydrogen bonding will affect HOMO-3. At the AM1 level computational results indicate that P2, P4 will easily convert to P1, P3, respectively. Thus, P1 and P3 will be the preferable products. The energy of conversion of P3 into P1 is estimated to be 37.2 kJ/mol under acidic conditions. As a result, a thermodynamic equilibrium will exist between P1 and P3, which is in agreement with 1HNMR experiments.更多还原