Jabłoński Mirosław
Department of Quantum Chemistry, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, 7-Gagarina St., PL-87 100 Toruń, Poland.
J Phys Chem A. 2015 May 21;119(20):4993-5008. doi: 10.1021/acs.jpca.5b02041. Epub 2015 May 5.
Using DFT-based calculations with seven exchange-correlation functionals (BP86, B3LYP, B3PW91, PBE0, TPSSh, M06-L, M06) we have performed comparative studies on α-, β-, γ-, and δ-agostic bonds (ABs) and intramolecular charge-inverted hydrogen bonds (IMCIHBs). Our detailed analysis of values of QTAIM parameters computed at bond (BCP) and ring critical points (RCP) as well as of the curvatures of bond paths tracing agostic bonds and intramolecular charge-inverted hydrogen bonds gives the opportunity to distinguish between both these types of interactions. In the case of molecules with agostic bonds, the BCP is significantly closer to the agostic hydrogen, whereas in systems with IMCIHB the BCP is, instead, somewhat closer to the metal atom. Agostic bonds are characterized by H···M bond paths being straight in the BCP···M section and then highly curved near the agostic hydrogen, whereas in the case of IMCIHB any substantial curvature of BP in the vicinity of hydrogen is not present. Quite the contrary, the significant curvature of BP near the metal atom can be obtained, instead. One can also distinguish IMCIHBs and ABs on the basis of values of bond ellipticity at BCP and the electron density at RCP which are either somewhat (PBE0) or considerably (M06) greater for the latter type of interaction. It has also been shown that, in general, the exchange-correlation functional has small influences on most of QTAIM parameters computed at BCP and RCP. More significant influences have only been obtained for Laplacian of the electron density, some its components, and the bond ellipticity.
我们使用基于密度泛函理论（DFT）的计算方法以及七种交换相关泛函（BP86、B3LYP、B3PW91、PBE0、TPSSh、M06-L、M06），对α-、β-、γ-和δ-螯合键（ABs）以及分子内电荷反转氢键（IMCIHBs）进行了比较研究。我们对在键临界点（BCP）和环临界点（RCP）处计算得到的量子拓扑原子理论（QTAIM）参数值，以及追踪螯合键和分子内电荷反转氢键的键路径曲率进行了详细分析，从而有机会区分这两种相互作用类型。对于具有螯合键的分子，BCP明显更靠近螯合氢，而在具有IMCIHB的体系中，BCP反而更靠近金属原子。螯合键的特征是H···M键路径在BCP···M段是直的，然后在螯合氢附近高度弯曲，而在IMCIHB的情况下，氢附近的BP不存在任何明显的曲率。相反，可以得到金属原子附近BP的明显曲率。人们还可以根据BCP处的键椭圆率值和RCP处的电子密度来区分IMCIHBs和ABs，对于后一种相互作用类型，这些值要么略有增加（PBE0），要么显著增加（M06）。研究还表明，一般来说，交换相关泛函对在BCP和RCP处计算得到的大多数QTAIM参数影响较小。仅对电子密度的拉普拉斯算子、其一些分量以及键椭圆率有更显著的影响。
