铂钌团簇及电荷对甲醇活性的理论研究

采用密度泛函理论(DFT)对钌掺杂的铂团簇阳离子(Pt_nRu_m]⁺, m + n = 3, n ≥ 1)活化甲醇C―H和O―H键反应进行了理论研究;探讨了电荷对Pt_nRu_m]团簇反应活性的影响。电荷分析表明:(1) Pt₃]⁺团簇中正电荷在三个Pt原子上均匀分布;掺杂Ru原子后,正电荷主要分布在Ru原子上; (2)首先活化C―H键时Pt_nRu_m]⁺的反应活性比Pt_nRu_m]明显提高;首先活化O―H键时只有Pt₃]⁺比Pt₃]团簇的反应活性有明显提高。本研究可为金属团簇调控的C―H键和O―H键的活化提供更深入的理解。

A Theoretical Study on the Reactivity and Charge Effect of PtRu Clusters toward Methanol Activation

Density functional theory (DFT) calculations were performed to gain mechanistic insight into the methanol C―H and O―H bond activations mediated by ruthenium-doped platinum cationic clusters Pt_nRu_m]⁺ (m + n = 3, n ≥ 1). The charge effect on the reactivity has been elucidated. Calculations show that positive charge is evenly distributed on the three Pt atoms of the Pt₃]⁺ cluster, while in the Ru-doped clusters, positive charge is mainly distributed on the Ru atom(s). The reactivity of Pt_nRu_m]⁺ is significantly greater than neutral Pt_nRu_m] during the initial C―H bond cleavage, while only Pt₃]⁺ exhibits greater reactivity than Pt₃] in the course of O―H bond cleavage. This study may aid in deeper understanding of C―H/O―H bond activations mediated by metal clusters.