Stortz Carlos A, Sarotti Ariel M
Universidad de Buenos Aires, Facultad de Ciencias Exactas, Departamento de Química Orgánica, Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR) Ciudad Universitaria, Pab. 2 1428 Buenos Aires Argentina
Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario Suipacha 531 Rosario 2000 Argentina
RSC Adv. 2019 Aug 5;9(42):24134-24145. doi: 10.1039/c9ra03524a. eCollection 2019 Aug 2.
The conformational landscape of 22 different non, mono-, and disubstituted compounds with a five-membered ring was thoroughly explored by (MP2) and DFT (B3LYP and M06-2X) methods with the 6-311+G** basis set. Our results showed that the conformational preference of these compounds was governed mainly by the specific characteristics of the substituents, with a minor influence of the level of theory employed. After a detailed analysis of the computational data, we found an interesting preference of the electronegative substituents to take pseudo-axial positions, whereas alkyl groups preferred adopting the pseudo-equatorial locations. Such preferences were pronounced with MP2 and M06-2X and underestimated by B3LYP. Despite each level of theory affording different landscapes in many cases, as a general trend, we noticed that M06-2X afforded much higher correlation with the MP2 results than B3LYP.
采用（MP2）和DFT（B3LYP和M06 - 2X）方法，在6 - 311 + G**基组下，对22种不同的含五元环的非取代、单取代和双取代化合物的构象态势进行了全面探索。我们的结果表明，这些化合物的构象偏好主要由取代基的特定特征决定，所采用的理论水平影响较小。在对计算数据进行详细分析后，我们发现一个有趣的现象，即电负性取代基倾向于占据假轴向位置，而烷基则更倾向于采取假赤道位置。MP2和M06 - 2X方法下这种偏好很明显，而B3LYP方法则低估了这种偏好。尽管在许多情况下每种理论水平给出的态势不同，但总体趋势是，我们注意到M06 - 2X与MP2结果的相关性比B3LYP高得多。
