Szatyłowicz Halina, Krygowski Tadeusz M, Panek Jarosław J, Jezierska Aneta
Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
J Phys Chem A. 2008 Oct 9;112(40):9895-905. doi: 10.1021/jp803592v.
The hydrogen-bonded isoelectronic complexes of aniline with HF/F- and an ionic form of aniline with HF were investigated by use of computational methods: Symmetry-Adapted Perturbation Theory (SAPT), Atoms in Molecules (AIM), and Natural Bond Orbitals (NBO) approaches. All computations were based on structural models previously generated at the B3LYP/6-311+(d,p) level. The differences between neutral (Ph-NH2...HF)and anionic (Ph-NH2...F- and Ph-NH-...HF) complexes were clearly outlined. The discussed charged complexes serve as Lewis acids and base, HF and F-, respectively. It was found that electrostatic and induction energy terms, obtained as a result of the SAPT method, are most dependent on the type of H-bonding (i.e.,charged or neutral). The electrostatic term is the most distinctive between the neutral and charge-assisted hydrogen bonds in the investigated two-body systems, whereas the latter is more significant in the case of weaker interactions (larger H...B distances). Application of Principal Component Analysis (PCA) to energy components obtained from the SAPT procedure indicated that all of them are relatively well intercorrelated.The above-mentioned terms together with the exchange energy terms are the most important contributions ofthe main principal component, which describes 95% of the total variance. Comparison of AIM parameters in bond critical points for modeled H-bond systems shows a good agreement with those from equilibrium complexes, both experimental and calculated ones. It was found that charged H-bonded complexes exhibit larger fluctuation of electron density and its Laplacian in bond critical points, in line with SAPT analysis. NBO results confirmed the effect of the strength of interaction on property changes both in the region of H-bonding and outside of it. The latter, more distant consequences follow the Bent-Walsh rule for all studied complexes.
利用计算方法，即对称适配微扰理论（SAPT）、分子中的原子（AIM）和自然键轨道（NBO）方法，研究了苯胺与HF/F - 的氢键等电子络合物以及苯胺离子形式与HF的络合物。所有计算均基于先前在B3LYP/6 - 311 + (d,p)水平生成的结构模型。清晰地勾勒出了中性（Ph - NH₂...HF）和阴离子（Ph - NH₂...F - 和Ph - NH⁻...HF）络合物之间的差异。所讨论的带电络合物分别作为路易斯酸和碱，即HF和F - 。结果发现，通过SAPT方法获得的静电能和诱导能项最依赖于氢键的类型（即带电或中性）。在研究的二体系统中，静电项在中性和电荷辅助氢键之间最为显著，而后者在较弱相互作用（较大的H...B距离）情况下更为重要。将主成分分析（PCA）应用于从SAPT程序获得的能量成分表明，它们之间的相关性相对较好。上述项与交换能项是主要主成分中最重要的贡献，该主成分描述了总方差的95%。对建模氢键系统的键临界点处的AIM参数进行比较，结果表明与平衡络合物（包括实验和计算得到的）的参数吻合良好。结果发现，带电氢键络合物在键临界点处表现出更大的电子密度及其拉普拉斯算子波动，这与SAPT分析一致。NBO结果证实了相互作用强度对氢键区域内外性质变化的影响。对于所有研究的络合物，后者更遥远的结果遵循Bent - Walsh规则。
