• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >One-Bond (~(1d)J_(H-H)) and Three-Bond ~(3d)J_(X-M)) Spin-Spin Coupling Constants Across X-H…H-M Dihydrogen Bonds
【24h】

One-Bond (~(1d)J_(H-H)) and Three-Bond ~(3d)J_(X-M)) Spin-Spin Coupling Constants Across X-H…H-M Dihydrogen Bonds

机译：X-H…H-M二氢键上的一键（〜（1d）J_（H-H））和三键〜（3d）J_（X-M））自旋-自旋耦合常数

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

In our continuing effort to identify NMR spin-spin coupling constants as fingerprints for hydrogen bond type and use these to obtain structural information, EOM-CCSD calculations have been performed to determine one-bond (~(1d)J_(H-H)) and three-bond (~(3d)J_(X-M)) spin-spin coupling constants across X-H…H-M dihydrogen bonds for complexes with ~(13)C-~1H, ~(15)N-~1H, and ~(17)O-~1H proton-donor groups and proton-acceptor metal hydries ~7Li-~1H and ~(23)Na-~1H. Unlike two-bond spin-spin coupling constants across N-H-N, N-H-O, O-H-O, and Cl-H-N hydrogen bonds that are determined solely by the Fermi-contact term, ~(1d)J_(H-H) receives nonnegligible contributions from the paramagnetic spin-orbit and diamagnetic spin-orbit terms. However, these terms tend to cancel, so that the curve for the distance dependence of ~(1d)J_(H-H) is determined by the distance dependence of the Fermi-contact term. The value of ~(1d)J_(H-H) is dependent on the nature of the proton donor and proton acceptor, and the relative orientation of the bonded pair. Hence, it would be difficult to extract structural information from experimentally measured coupling constants unless EOM-CCSD calculations were performed on a model complex that closely resembles the experimental complex. ~(3d)J_(C-Li) values for the equilibrium structures of seven linear complexes stabilized by C-H…H-Li bonds are dependent on C-Li distances, and are also sensitive to structural changes which remove any one of these four atoms from the dihydrogen bond. ~(3d)J_(O-M) for the complexes HOH:HLi and HOH:HNa exhibit unusual behavior as a function of the O-M distance, increasing with increasing distance through a change of sign, reaching a maximum, and then subsequently decreasing.
机译：在我们不断努力地将NMR自旋-自旋偶合常数识别为氢键类型的指纹并使用它们来获得结构信息的过程中，已进行EOM-CCSD计算以确定单键（〜（1d）J_（HH））和三个带有（（13）C-〜1H，〜（15）N-〜1H和〜（17）O的配合物的XH…HM二氢键上的（-（3d）J_（XM））自旋-自旋偶合常数-〜1H质子供体基团和质子受体金属水合物〜7Li-〜1H和〜（23）Na-〜1H。与仅由费米接触项确定的跨NHN，NHO，OHO和Cl-HN氢键的双键自旋自旋偶合常数不同，〜（1d）J_（HH）从顺磁自旋轨道获得不可忽略的贡献和反磁性自旋轨道项。但是，这些项趋向于抵消，因此〜（1d）J_（H-H）的距离相关性曲线由费米接触项的距离相关性确定。 〜（1d）J_（H-H）的值取决于质子供体和质子受体的性质以及键合对的相对取向。因此，除非在与实验复杂度非常相似的模型复杂度上进行EOM-CCSD计算，否则很难从实验测量的耦合常数中提取结构信息。由CH…H-Li键稳定的七个线性络合物的平衡结构的〜（3d）J_（C-Li）值取决于C-Li距离，并且对除去这四个原子中任何一个的结构变化敏感从二氢键。配合物HOH：HLi和HOH：HNa的〜（3d）J_（O-M）表现出与O-M距离有关的异常行为，通过符号变化随距离增加而增加，达到最大值，然后减小。

著录项

相似文献

  • 外文文献
  • 中文文献
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