On the interplay between CH...O and OH...O interactions in determining crystal packing and molecular conformation: an experimental and theoretical charge density study of the fungal secondary metabolite austdiol (C12H12O5).
On the interplay between CH...O and OH...O interactions in determining crystal packing and molecular conformation: an experimental and theoretical charge density study of the fungal secondary metabolite austdiol (C12H12O5).
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关于 CH...O 和 OH...O 相互作用在确定晶体堆积和分子构象中的相互作用：真菌次生代谢物 austdiol (C12H12O5) 的实验和理论电荷密度研究。
DOI：
10.1021/jp056823y
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
R. Destro
中科院分区：
文献类型：
--
作者：
L. Lo Presti;R. Soave;R. Destro
从一系列在T=70(1)K下收集的单晶X射线衍射峰获得了真菌代谢物Austdiol(1)的总实验电子密度Rho(R)及其拉普拉斯倒数差Rho(R)、分子偶极矩、静电势Phi(R)和分子间相互作用能.实验结果与孤立分子密度泛函理论计算和全周期计算结果进行了比较。(1)的晶体结构由沿一个晶胞轴线延伸的锯齿状条带组成，由分子通过OH…O和CH…O相互作用连接而成，而在垂直方向上，相邻的分子通过较短的CH...O分子间的接触而相连。对所有分子内和分子间的H...O相互作用进行了广泛的定量研究，不仅基于几何标准，而且基于Rho(R)的拓扑分析，以及相关的能量学评估，使我们(I)能够评估OH...O和CH...O相互作用在决定分子构象和晶体堆积中的相互作用；(Ii)鉴定那些是真正的氢键(HBs)的CH...O接触；(Iii)确定相对氢键强度。给出了一个实验的定量证据，证明CH...O HBs与传统的OH...O HBs非常相似，尽管总体上更弱。实验电偶极矩与理论电偶极矩的比较表明，结晶过程中发生了明显的电荷重排，说明了晶体中HBs的相互协同作用。报道了用不同的理论方法得到的分子间总相互作用能和静电能贡献，并与实验结果进行了比较。结果表明，Spackman提出的基于分子电荷密度近似穿透对分子间静电能贡献的新方法，在大多数情况下都能预测正确的相对静电相互作用能。
The total experimental electron density rho(r), its Laplacian inverted delta(2)rho(r), the molecular dipole moment, the electrostatic potential phi(r), and the intermolecular interaction energies have been obtained from an extensive set of single-crystal X-ray diffracted intensities, collected at T = 70(1) K, for the fungal metabolite austdiol (1). The experimental results have been compared with theoretical densities from DFT calculations on the isolated molecule and with fully periodic calculations. The crystal structure of (1) consists of zigzag ribbons extended along one cell axis and formed by molecules connected by both OH...O and CH...O interactions, while in a perpendicular direction, adjacent molecules are linked by short CH...O intermolecular contacts. An extensive, quantitative study of all the intra- and intermolecular H...O interactions, based not only on geometrical criteria, but also on the topological analysis of rho(r), as well as on the evaluation of the pertinent energetics, allowed us (i) to assess the mutual role of OH...O and CH...O interactions in determining molecular conformation and crystal packing; (ii) to identify those CH...O contacts which are true hydrogen bonds (HBs); (iii) to determine the relative hydrogen bond strengths. An experimental, quantitative evidence is given that CH...O HBs are very similar to the conventional OH...O HBs, albeit generally weaker. The comparison between experimental and theoretical electric dipole moments indicates that a noticeable charge rearrangement occurs upon crystallization and shows the effects of the mutual cooperation of HBs in the crystal. The total intermolecular interaction energies and the electrostatic energy contribution obtained through different theoretical methods are reported and compared with the experimental results. It is found that the new approach proposed by Spackman, based on the use of the promolecular charge density to approximate the penetration contribution to intermolecular electrostatic energies, predicts the correct relative electrostatic interaction energies in most of the cases.