Osuna Sílvia, Morera Josep, Cases Montserrat, Morokuma Keiji, Solà Miquel
Institut de Química Computacional and Departament de Química, Universitat de Girona, Campus de Montilivi, E-17071 Girona, Catalonia, Spain.
J Phys Chem A. 2009 Sep 3;113(35):9721-6. doi: 10.1021/jp904294y.
In this article, we theoretically analyze the Diels-Alder cycloaddition between cyclopentadiene and C60 for which experimental results on energy barriers and reaction energies are known. The comparison of the results obtained with the two-layered ONIOM approach using different partitions for the high- and low-level layers with those obtained employing the B3LYP/6-31G(d) method for the entire system allows us to conclude that the partition including a pyracylene unit of C60 in the description of the high-level layer is enough to get excellent results. Using this partition in the two-layered ONIOM approach, we have computed the energy barriers and reaction energies for this Diels-Alder reaction for different functionals, and we have compared them with experimental data. From this comparison, both the ONIOM2(M06-2X/6-31G(d):SVWN/STO-3G) and the M06-2X/6-31G(d)//ONIOM2(B3LYP/6-31G(d):SVWN/STO-3G) methods are recommended as reliable and computationally affordable approaches to be exploited for the study of the chemical reactivity of [6,6]-bonds in fullerenes and nanotubes.
在本文中，我们从理论上分析了环戊二烯与C60之间的狄尔斯-阿尔德环加成反应，已知该反应的能垒和反应能量的实验结果。将使用不同高低层划分的两层ONIOM方法得到的结果与对整个体系采用B3LYP/6-31G(d)方法得到的结果进行比较，我们可以得出结论，在高层描述中包含C60的苝单元的划分足以得到优异的结果。在两层ONIOM方法中使用这种划分，我们计算了该狄尔斯-阿尔德反应在不同泛函下的能垒和反应能量，并将它们与实验数据进行了比较。通过这种比较，ONIOM2(M06-2X/6-31G(d):SVWN/STO-3G)方法和M06-2X/6-31G(d)//ONIOM2(B3LYP/6-31G(d):SVWN/STO-3G)方法都被推荐为可靠且计算成本可承受的方法，可用于研究富勒烯和纳米管中[6,6]-键的化学反应性。
