...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Structural Chemistry >Fully and partially exohydrogenated Si80 fullerene cage: a DFT study
【24h】

Fully and partially exohydrogenated Si80 fullerene cage: a DFT study

机译：完全和部分氢化的Si80富勒烯笼：DFT研究

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We have performed a density functional study to investigate electronic and magnetic properties of fully and partially exohydrogenation in the Si_(80) fullerene cage based on NMR parameters, nucleus-independent chemical shift (NICS) indices and natural population analysis. Hydrogenation of 20 silicons inside and 60 silicons outside results in two distinct values for the ~(29)Si σ_(iso), and also for ~(29)Si ?σ. NICS yields negative value of-1.5 ppm at the cage center of the fully exohydrogenated fullerene, Si_(80)H_(80). However, NICS yields positive value of 1.5 ppm at the cage center of the partially exohydrogenated fullerene, H_(20)@Si_(80)H_(60), then becomes more negative along the axis toward the center of pentagon until reaching -3.0 ppm at the ring center (and -4.3 at the point 1 A ° away from the ring center outside), suggesting that in this case pentagons can be considered as aromatic fragments. H_(20)@Si_(80)H_(60) cage is composed of negatively charged hydrogen atoms and positively charged silicon atoms, indicating electron transfer from silicon atoms on the surfaces of the cage to the chemically bonded hydrogen atoms. A decreasing trend is observed for ~1H σ_(iso) values as the natural charges of hydrogen sites in these fullerenes increase while no regular trend is observed for the chemical shielding anisotropy ?σ of hydrogen atoms.
机译：我们已经进行了密度泛函研究，以基于N​​MR参数，不依赖核的化学位移（NICS）指数和自然种群分析研究Si_（80）富勒烯笼中的全部和部分外加氢的电子和磁性。内部的20个硅和外部的60个硅的氢化导致〜（29）Siσ_（iso）和〜（29）Siσσ的两个不同值。 NICS在完全外加氢的富勒烯Si_（80）H_（80）的笼中心产生负值-1.5 ppm。但是，NICS在部分外氢化的富勒烯的笼中心H_（20）@Si_（80）H_（60）处产生1.5 ppm的正值，然后沿朝向五边形中心的轴变得更负，直到达到-3.0 ppm在五环中（在距五环中心1 A°处为-4.3处），这表明五边形可被视为芳族碎片。 H_（20）@Si_（80）H_（60）笼由带负电的氢原子和带正电的硅原子组成，表明电子从笼表面的硅原子转移到化学键合的氢原子。这些富勒烯中氢位点的天然电荷增加时，〜1Hσ_（iso）值会下降，而氢原子的化学屏蔽各向异性Δσ则没有规律的趋势。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号