尹人香蕉久久99天天拍

题目：Boron Double-Chains and Fluxional Bonds in Boron  Nanostructures

报告人：Prof.Si-Dian Li

 （Institute of Molecular Science, Shanxi University）

时间：2018年8月10日14：30

地点：明故宫校区A9-402

主办单位：机械结构力学及控制国家重点实验室、校科协、航空宇航学院

报告内容介绍：

The novel structural and bonding patterns of boron nanoclusters have  attracted considerable attention in both chemistry and materials science in recent years. We  present herein the latest combined experimental and theoretical investigations  on cage-like borospherenes B_n^q (q=n-40, n=36-40),  metal-doped heteroborospherenesNi_n∈叠₄₀ (n=1-6),  planar borophenes (Fig.1),metal-doped Ni₂∈叠₁₄  heteroborophenes,  tubular molecular rotors  B₂-Ta@B₁₈^-, B₃-Ta@B₁₈,  and B₄-Ta@B₁₈⁺, and the tubular to cage-like  structural transition in metal-centered boron clusters at  Ta@B₂₂^- with the coordination number of CN=22. These  nanostructures are dominated by boron double chains (BDCs), in which planar B₁₉^-, tubular  Ta@B₂₀^-, and cage-like  B₃₉^- exhibit almost barrier-free structural fluctuations at room  temperature due to the existence of fluxional bonds (FBs) in electron-deficient systems (Fig.2). ^1-6 Fluxional  bondsexistin the region between two  quasi-rotational components of the systems which rotate against each other. FBs  as an extension of the classic localized bonds (2c-2e bonds) and delocalized  bonds (mc-2e bonds, m≥3) in chemistry may have important applications in molecular  dynamics, aromatic properties, catalysis mechanisms, and electronics materials.  Boron-based nanostructures possess properties complementary to carbon  nanostructures and may find wide applications in catalysis, energy-storage, and  electronics materials.

报告人介绍：

Si-Dian Li is a professor of chemistry in the Institute of Molecular  Science at Shanxi University, P. R. China. He received his B.S. from Beijing  Normal University in 1985, M.S. from Shanxi University in 1988, and Doctor of  Engineering from Xi’an Jiaotong University in 2003. Before moving to Shanxi  University in 2011, he served as the president of Xinzhou Teachers’ University  from 2000 to 2011 and the president of Taiyuan Teachers’ College from 1996 to  2000.

Prof. Li has carried out joint researches at the University of Sussex  in the UK, Pacific Northwest National Laboratory in the US, and Brown  University. His fields of interests include theoretical and experimental  research in structural chemistry, materials chemistry, and computational  chemistry. His group in the past decade have been focusing on planar  tetracoordinate carbons and silicons (J. Am. Chem. Soc., 2004, 2005; Angew Chem  Int. Ed. 2004, 2005), boronyl (BO) chemistry (JACS, 2008; Acc. Chem. Res.,  2014), all-boron fullerenes (borospherenes) (B₄₀^-/0:  Nature Chemistry, 2014 and B₃₉^-: ACS NANO, 2015),  metalloborospherenes (Angew Chem Int. Ed. 2015, Nanosacle, 2018),  heteroboronanotubes (Nanoscale, 2016, 2017; Chem. Comm.,2016), and monolayer  (2D) heteroborophenes (JCP 2013, Sci. Reports, 2017) with over 140 papers  published in various international journals in total. He and his group recently  proposed the concept of fluxional bonds (FBs) as an extension the traditional  localized bonds and delocalized bonds in chemistry.

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