中心质子化对Keggin型ɑ-[H_xW_(12)O_(40)]^(8-x)-(x=1～4)结构性能影响的DFT研究:笼内约束氢键的电子结构(I)  

Effects of central protonation on relationships of structures and properties of the Keggin-type ɑ-[H_xW_(12)O_(40)]^(8-x)-(x=1–4):The electronic structures with constraint hydrogen bonds in the cage(I)

作　　者：王金月[1] 罗华锋[1] 吴同[1] 王健[1] 王藩侯[1] 胡常伟[2] 熊燕[3] 

机构地区：[1]四川省高校计算物理重点实验室,应用化学研究所,宜宾学院,宜宾644007 [2]绿色化学与技术教育部重点实验室,四川大学化学学院,成都610064 [3]重庆大学化学化工学院,重庆400044

出　　处：《科学通报》2014年第10期895-904,1-5,共10页Chinese Science Bulletin

基　　金：四川省教育厅重点实验室专项(2006ZD051);宜宾学院重点项目(2009z06);宜宾学院博士科研资助项目(2006B03);国家自然科学基金(20072024);中央高校基本科研业务费专项资金(CDJZR11220005;CQDXWL-2013-Z012);重庆市科委项目(cstc2013jcyjA10037)资助

摘　　要：在前期理论研究的基础上,进一步采用密度泛函理论(DFT)中的O3LYP方法,研究了具有不同数目的中心质子对?-[HxW12O40](8?x)?(x=1~4)的几何结构和电子结构的影响.在LanL2DZ基组水平下,优化得到了各物种的稳定构型,并对优化好的构型作了NBO计算分析.研究发现,Keggin金属氧笼内质子的进入,对标题化合物的中心结构产生了较大影响,这些中心质子不仅被Keggin的金属氧笼"包合",而且与Keggin的4个中心氧之间构成了不同类型的四面体结构,同时还形成了强弱和取向不同的"笼内氢键",这些氢键受到Keggin金属氧笼(直径约7?)的"束缚"而成为"笼内约束氢键".基于键价(BV)模型,对这些特殊的分子内氢键进行了系统分析,首次提出了?-[HxW12O40](8?x)?的中心质子数具有"饱和性",并推测了标题化合物金属氧笼内质子的饱和度为6.这就从理论上科学回答了该类化合物金属氧笼中心到底能够容纳多少质子的困惑问题.Based on the previous theoretical research, the DFT/O3LYP method has been further used to investigate the geometric and electronic structures of α-[UxW12O40]（8-x）- （x=14） influenced by the different central protons. All the title species concerned have been fully optimized in the gas phase at the O3LYP/LanL2DZ theory level, thereafter, NBO analysis were performed on the optimized structures. It has been shown that, central geometric structures of the title Keggin cages were greatly influenced by the central protons, which not only surrounded by the metal-oxygen cage, but also formed different center tetrahedral structures with the four center oxygen atoms. Besides, the central protons have been formed different strength and orientation hydrogen-bonds in the Keggin cage with the four central oxygen atoms. These hydrogen-bonds are the constrained ones caused by the restraining from rigid metal-oxygen cage （-0.7 diameter）. The differences between the central tetrahedrons and the special intramolecular hydrogen-bonds have been fully analyzed and compared based on the bond valence （BV） model. The saturability of central protons in the α-[HxW12O40]（8-x） （x=1-4） metal- oxygen cage is put forward for the first time. And the maximum number of protons accommodated by the cavity of α-Keggin type metatungstates is supposed to be six. So, the puzzle question ＂how many protons can be accommodated in the α-Keggin cavity＂ is solved scientifically from the theoretic point of view.

关 键 词：α-Keggin型 偏钨酸 中心质子化 笼内氢键 质子饱和性 键价模型 密度泛函理论 

分 类 号：O641.1[理学—物理化学]