Parreira Renato L T, Galembeck Sérgio E
Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida dos Bandeirantes 3900, Ribeirão Preto, 14040-901 SP, Brazil.
J Am Chem Soc. 2003 Dec 17;125(50):15614-22. doi: 10.1021/ja036846v.
The hydrogen bonds formed between the hydroperoxyl radical and formic, acetic, and trifluoroacetic acids were characterized using geometric, energetic, and electronic parameters through calculations done with the UB3LYP/6-311++G (3df,3pd) and UB3LYP/EPR-III methods. The wave functions were analyzed through the natural bond orbital, natural steric analysis, natural resonance theory, and atoms in molecules methods. The energy decomposition method proposed by Xantheas was used. The vibrational frequencies and the intensity of the O-H stretching bands, as well as the spin densities, were compared with experimental evidence. The results allowed the characterization of the hydrogen bonds formed in the complexation of the acids with the hydroperoxyl radical. Complexation led to significant alterations in the equilibrium geometry of the monomers. Energetic analysis proved that the studied complexes are stable and allowed the understanding of the effect of the electron-donating and electron-withdrawing groups in their stabilization. The alterations in the electronic structure of the monomers after complexation led to an increase in the resonance of the carboxyl group, which can be partially attributed to the hydrogen bond.
通过使用UB3LYP/6 - 311++G(3df,3pd)和UB3LYP/EPR - III方法进行计算，利用几何、能量和电子参数对氢过氧自由基与甲酸、乙酸和三氟乙酸之间形成的氢键进行了表征。通过自然键轨道、自然空间分析、自然共振理论和分子中的原子方法对波函数进行了分析。使用了Xantheas提出的能量分解方法。将O - H伸缩带的振动频率和强度以及自旋密度与实验证据进行了比较。结果使得能够对酸与氢过氧自由基络合过程中形成的氢键进行表征。络合导致单体平衡几何结构发生显著变化。能量分析证明所研究的络合物是稳定的，并有助于理解供电子和吸电子基团在其稳定性中的作用。络合后单体电子结构的变化导致羧基共振增加，这部分可归因于氢键。
