Yang Mengzhou, Zhang Hanyu, Jia Yuhan, Yin Baoqi, Luo Zhixun
Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences. Beijing 100190, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
J Phys Chem A. 2020 May 21;124(20):4087-4094. doi: 10.1021/acs.jpca.0c02350. Epub 2020 May 12.
Utilizing the homemade reflection time-of-flight mass spectrometer (Re-TOFMS), here we report a comprehensive study of the reactivity of aluminum clusters Al with molecular benzene in the gas-phase flow tube reactor. During the reactions with benzene, Al clusters were found to be relatively more reactive than Al, and interestingly, the Al cluster exhibited more reaction product than its neighboring Al clusters. With an emphasis on Al clusters, we have performed an in-depth study utilizing DFT calculations to unravel the diverse reactivity of aluminum clusters with benzene. It is revealed that the AlBz cluster has a short Al-C distance and high binding energy, as well as an enlarged HOMO-LUMO gap in comparison with that of Al. This contrasts with Al and Al, of which the HOMO-LUMO gaps are reduced when the cluster binds with a benzene molecule. Further, the cluster-π interactions between aluminum clusters and benzene are fully demonstrated via topological analysis, natural bonding orbital (NBO) analysis, and noncovalent interaction plots based on independent gradient model (IGM). The unique gyro-like structure of Al and cluster-π interaction induce uneven redistribution of charges on the 13- atoms of Al, enabling a tight Al-C bond with strong electrostatic attraction and orbital interactions, which largely differs from the weak orbital overlap and electrostatic repulsion between benzene molecule and Al clusters.
利用自制的反射飞行时间质谱仪（Re-TOFMS），我们在此报告了一项关于气相流动管反应器中铝簇Al与分子苯反应活性的综合研究。在与苯的反应过程中，发现铝簇比Al更具反应活性，有趣的是，Al簇比其相邻的铝簇表现出更多的反应产物。重点关注铝簇，我们利用密度泛函理论（DFT）计算进行了深入研究，以揭示铝簇与苯的不同反应活性。结果表明，与Al相比，AlBz簇具有较短的Al-C距离和较高的结合能，以及增大的最高占据分子轨道-最低未占据分子轨道（HOMO-LUMO）能隙。这与Al和Al不同，当簇与苯分子结合时，它们的HOMO-LUMO能隙会减小。此外，通过拓扑分析、自然键轨道（NBO）分析以及基于独立梯度模型（IGM）的非共价相互作用图，充分证明了铝簇与苯之间的簇-π相互作用。Al独特的陀螺状结构和簇-π相互作用导致Al的13个原子上电荷分布不均，从而形成具有强静电吸引力和轨道相互作用的紧密Al-C键，这与苯分子和铝簇之间微弱的轨道重叠和静电排斥有很大不同。
