Olvera-Neria Oscar, Avilés Roberto, Francisco-Rodríguez Héctor, Bertin Virineya, García-Cruz Raúl, González-Torres Julio César, Poulain Enrique
Área de Física Atómica Molecular Aplicada (FAMA), CBI, Universidad Autónoma Metropolitana-Azcapotzalco, Av. San Pablo 180, Col. Reynosa Tamaulipas, Mexico, D. F., 02200, Mexico,
J Mol Model. 2015 Apr;21(4):80. doi: 10.1007/s00894-015-2633-1. Epub 2015 Mar 11.
Nitrous oxide (N2O) is a by-product of exhaust pipe gases treatment produced by motor vehicles. Therefore, the N2O reduction to N2 is necessary to meet the actual environmental legislation. The N2O adsorption and dissociation assisted by the square-based pyramidal Rh5 cluster was investigated using the density functional theory and the zero-order regular approximation (ZORA). The Rh5 sextet ground state is the most active in N2O dissociation, though the quartet and octet states are also active because they are degenerate. The Rh5 cluster spontaneously activates the N2─O cleavage, and the reaction is highly exothermic ca. -75 kcal mol(-1). The N2─O breaking is obtained for the geometrical arrangement that maximizes the overlap and electron transfers between the N2O and Rh5 frontier orbitals. The Rh5 high activity is due to the Rh 3d orbitals are located between the N2O HOMO and LUMO orbitals, which makes possible the interactions between them. In particular, the O 2p states strongly interact with Rh 3d orbitals, which finally weaken the N2─O bond. The electron transfer is from the Rh5 HOMO orbital to the N2O antibonding orbital.
一氧化二氮（N₂O）是机动车尾气处理产生的副产物。因此，将N₂O还原为N₂对于符合实际环境法规是必要的。利用密度泛函理论和零级正则近似（ZORA）研究了方形金字塔形Rh₅团簇辅助的N₂O吸附和解离。Rh₅六重态基态在N₂O解离中最具活性，尽管四重态和八重态也具有活性，因为它们是简并的。Rh₅团簇自发地激活N₂─O键的断裂，该反应是高度放热的，约为-75 kcal mol⁻¹。对于使N₂O和Rh₅前沿轨道之间的重叠和电子转移最大化的几何排列，获得了N₂─O键的断裂。Rh₅的高活性是由于Rh 3d轨道位于N₂O的HOMO和LUMO轨道之间，这使得它们之间的相互作用成为可能。特别是，O 2p态与Rh 3d轨道强烈相互作用，最终削弱了N₂─O键。电子从Rh₅的HOMO轨道转移到N₂O的反键轨道。
