Matousek Jirí, Kulhánek Petr, Cajan Michal, Koca Jaroslav
National Centre for Biomolecular Research, Faculty of Science, Masaryk University in Brno, Kotlárská 2, CZ-611 37 Brno, Czech Republic.
J Phys Chem A. 2006 Jan 26;110(3):861-7. doi: 10.1021/jp055415r.
The pinched cone-pinched cone interconversion (PCI) of tetraethoxy substituted calix[4]arene and thiacalix[4]arene was studied by means of molecular dynamics using the GAFF force field and quantum mechanics. Influence of solvent was expressed by changes in cavity geometries as well as in free energy barriers that were calculated using constrained MD simulations. Water and chloroform were found to reduce the energy barriers in comparison with vacuum simulations. Only qualitative agreement between energy barriers calculated by MD and experimental values was achieved. Also, quantum chemical calculations were performed with the RI-MP2 method, and a better description of PCI was achieved than that previously obtained by HF or DFT methods. The combination of qualitative MD data on solvated systems with RI-MP2 gas-phase data gave us very good agreement with experimental results.
利用GAFF力场和量子力学通过分子动力学研究了四乙氧基取代杯[4]芳烃和硫杂杯[4]芳烃的夹锥-夹锥相互转化（PCI）。溶剂的影响通过腔几何结构的变化以及使用受限分子动力学模拟计算的自由能垒来表示。与真空模拟相比，发现水和氯仿会降低能垒。分子动力学计算的能垒与实验值仅达成了定性一致。此外，采用RI-MP2方法进行了量子化学计算，对PCI的描述比之前通过HF或DFT方法得到的更好。溶剂化体系的定性分子动力学数据与RI-MP2气相数据相结合，使我们得到了与实验结果非常吻合的结果。
