Faculty of Chemistry, University of Wrocław, ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland.
Faculty of Chemistry, University of Warsaw, ul. Pasteura 1, 01-224 Warsaw, Poland.
Int J Mol Sci. 2021 Jul 27;22(15):8033. doi: 10.3390/ijms22158033.
Non-covalent interactions responsible for molecular features and self-assembly in Naphthazarin C polymorph were investigated on the basis of diverse theoretical approaches: Density Functional Theory (DFT), Diffusion Quantum Monte Carlo (DQMC), Symmetry-Adapted Perturbation Theory (SAPT) and Car-Parrinello Molecular Dynamics (CPMD). The proton reaction paths in the intramolecular hydrogen bridges were studied. Two potential energy minima were found indicating that the proton transfer phenomena occur in the electronic ground state. Diffusion Quantum Monte Carlo (DQMC) and other levels of theory including Coupled Cluster (CC) employment enabled an accurate inspection of Potential Energy Surface (PES) and revealed the energy barrier for the proton transfer. The structure and reactivity evolution associated with the proton transfer were investigated using Harmonic Oscillator Model of Aromaticity - HOMA index, Fukui functions and Atoms In Molecules (AIM) theory. The energy partitioning in the studied dimers was carried out based on Symmetry-Adapted Perturbation Theory (SAPT) indicating that dispersive forces are dominant in the structure stabilization. The CPMD simulations were performed at 60 K and 300 K in vacuo and in the crystalline phase. The temperature influence on the bridged protons dynamics was studied and showed that the proton transfer phenomena were not observed at 60 K, but the frequent events were noticed at 300 K in both studied phases. The spectroscopic signatures derived from the CPMD were computed using Fourier transformation of autocorrelation function of atomic velocity for the whole molecule and bridged protons. The computed gas-phase IR spectra showed two regions with OH absorption that covers frequencies from 2500 cm-1 to 2800 cm-1 at 60 K and from 2350 cm-1 to 3250 cm-1 at 300 K for both bridged protons. In comparison, the solid state computed IR spectra revealed the environmental influence on the vibrational features. For each of them absorption regions were found between 2700-3100 cm-1 and 2400-2850 cm-1 at 60 K and 2300-3300 cm-1 and 2300-3200 cm-1 at 300 K respectively. Therefore, the CPMD study results indicated that there is a cooperation of intramolecular hydrogen bonds in Naphthazarin molecule.
密度泛函理论（DFT）、扩散量子蒙特卡罗（DQMC）、对称自适应微扰理论（SAPT）和 Car-Parrinello 分子动力学（CPMD），研究了萘甲嗪 C 多晶型中非共价相互作用对分子特征和自组装的影响。研究了分子内氢键中的质子反应路径。发现了两个势能极小值，表明质子转移现象发生在电子基态。扩散量子蒙特卡罗（DQMC）和其他理论水平，包括耦合簇（CC）的应用，使我们能够准确地检查势能面（PES），并揭示质子转移的能量势垒。使用芳香性的谐振子模型 - HOMA 指数、福井函数和分子中的原子（AIM）理论研究了与质子转移相关的结构和反应性演化。基于对称自适应微扰理论（SAPT）对研究中的二聚体进行了能量分配，表明分散力在结构稳定化中占主导地位。在 60 K 和 300 K 下在真空中和晶体相中进行了 CPMD 模拟。研究了温度对桥连质子动力学的影响，结果表明在 60 K 时未观察到质子转移现象，但在两种研究相中的 300 K 时频繁发生。从 CPMD 导出的光谱特征是通过原子速度自相关函数的傅里叶变换计算得到的，用于整个分子和桥连质子。计算得出的气相 IR 光谱显示在 60 K 时，两个区域的 OH 吸收频率从 2500 cm-1 到 2800 cm-1，在 300 K 时为 2350 cm-1 到 3250 cm-1，适用于两个桥连质子。相比之下，固态计算的 IR 光谱揭示了环境对振动特征的影响。对于每个光谱，在 60 K 时分别在 2700-3100 cm-1 和 2400-2850 cm-1 以及在 300 K 时在 2300-3300 cm-1 和 2300-3200 cm-1 之间发现了吸收区域。因此，CPMD 研究结果表明，萘甲嗪分子中的分子内氢键具有协同作用。
