Báez-Grez Rodrigo, Inostroza Diego, Vásquez-Espinal Alejandro, Islas Rafael, Pino-Rios Ricardo
Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello República 275 Santiago Chile 8370146
Doctorado en Fisicoquímica Molecular, Facultad de Ciencias Exactas, Universidad Andres Bello República 275 Santiago Chile.
RSC Adv. 2023 Aug 15;13(35):24499-24504. doi: 10.1039/d3ra04308h. eCollection 2023 Aug 11.
A new algorithm called Automatic Johnson Cluster Generator (AJCG) is presented, which, as its name indicates, allows the definition of the desired Johnson polyhedron to subsequently carry out all the possible permutations between the atoms that form this polyhedron. This new algorithm allows the exhaustive study of the structures' potential energy surface (PES). In addition, the AJCG algorithm is helpful for the study of three-dimensional compounds such as boranes or Zintl clusters and their structural derivatives with two or more different atoms. The automatic filling of vertices is particularly useful in mixed compounds because of the possibility of taking into account all possible configurations in the structure. As a test system, we investigated the -type EM (E = Si, Ge, Sn; M = Sb, Bi) structure which has eight vertices and complies with Wade-Mingos rules. Initially, we defined a bipyramidal structure (10 vertices), and filled the vertices with the atoms in all possible configurations. Since the selected system has eight atoms, the two remaining vertices were filled with pseudo atoms to complete the structure. After re-optimizing the initial population generated with AJCG, a large number of isomers with energy below 10 kcal mol are identified. These results show that the most stable isomers possess homonuclear M-M bonds, except SnBi. Although the overall putative minima differ at the PBE0-D3 and DLPNO-CCSD(T) levels, they are always competitive minima. In addition to using high-precision methodologies to correctly study relative energies, applying solvent effects in highly charged systems becomes mandatory. The aromatic character of these studied systems was demonstrated qualitatively with two- and three-dimensional mapping and quantitatively by calculating the value of the z-component of the induced magnetic field at the cage center, including scalar and spin-orbit correction for relativistic effects. The compounds studied have a high degree of aromaticity, which allows us to establish that despite structural modifications (, from to ), the aromaticity is preserved.
提出了一种名为自动约翰逊簇生成器（AJCG）的新算法，顾名思义，它允许定义所需的约翰逊多面体，以便随后对构成该多面体的原子之间进行所有可能的排列。这种新算法有助于详尽研究结构的势能面（PES）。此外，AJCG算法对于研究硼烷或津特耳簇等三维化合物及其具有两个或更多不同原子的结构衍生物很有帮助。顶点的自动填充在混合化合物中特别有用，因为可以考虑结构中的所有可能构型。作为测试系统，我们研究了符合韦德 - 明戈斯规则的具有八个顶点的 - 型EM（E = Si、Ge、Sn；M = Sb、Bi）结构。最初，我们定义了一个双锥结构（10个顶点），并用所有可能的构型填充顶点。由于所选系统有八个原子，用虚拟原子填充剩下的两个顶点以完成结构。在用AJCG生成的初始种群重新优化后，识别出大量能量低于10 kcal/mol的异构体。这些结果表明，除了SnBi外，最稳定的异构体具有同核M - M键。尽管在PBE0 - D3和DLPNO - CCSD(T)水平上总的假定最小值不同，但它们始终是有竞争力的最小值。除了使用高精度方法正确研究相对能量外，在高电荷系统中应用溶剂效应变得必不可少。通过二维和三维映射定性地证明了这些研究系统的芳香性，并通过计算笼中心感应磁场的z分量值定量地证明了芳香性，包括相对论效应的标量和自旋 - 轨道校正。所研究的化合物具有高度的芳香性，这使我们能够确定，尽管有结构修饰（例如，从 到 ），芳香性仍然得以保留。
