...
  • 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 >Systematic ab initio study of N-15-N-15 and N-15-H-1 spin-spin coupling constants across N-H+-N hydrogen bonds: Predicting N-N and N-H coupling constants and relating them to hydrogen bond type
【24h】

Systematic ab initio study of N-15-N-15 and N-15-H-1 spin-spin coupling constants across N-H+-N hydrogen bonds: Predicting N-N and N-H coupling constants and relating them to hydrogen bond type

机译：贯穿N-H + -N氢键的N-15-N-15和N-15-H-1自旋-自旋偶联常数的系统从头算研究：预测N-N和N-H偶联常数并将它们与氢键类型相关

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

A systematic ab initio EOM-CCSD study of N-15-N-15 and N-15-H-1 spin-spin coupling constants has been carried out for a series of complexes formed from 11 nitrogen bases with experimentally measured proton affinities. When these complexes are arranged in order of increasing proton affinity of the proton-acceptor base and, for each proton acceptor, increasing order of proton affinity of the protonated N-H donor, trends in distances and signs of coupling constants are evident that are indicative of the nature of the hydrogen bond. All two-bond spin-spin coupling constants ((2h)J(N-N)) are positive and decrease as the N-N distance increases. All one-bond N-H coupling constants ((1)J(N-H)) are negative (K-1(N-H) are positive). (1)J(N-H) is related to the N-H distance and the hybridization of the donor N atom. One-bond (HN)-N-... coupling constants ((1h)J(H-N)) are positive (K-1h(H-N) are negative) for traditional hydrogen bonds, but (1h)J(H-N) becomes negative when the hydrogen bond acquires sufficient proton-shared character. The N-N and (HN)-N-... distances at which (1h)J(H-N) changes sign are approximately 2.71 and 1.62 angstrom, respectively. Predictions are made of the values of (2h)J(N-N) and (1)J(N-H), and the signs of (1h)J(H-N), for those complexes that are too large for EOM-CCSD calculations.
机译：已对由11个氮碱基形成的一系列配合物进行了实验测量的质子亲和力，对N-15-N-15和N-15-H-1自旋-自旋-自旋耦合常数进行了系统的从头开始的EOM-CCSD研究。当这些复合物按质子受体碱基的质子亲和力增加的顺序排列，并且对于每个质子受体，质子化NH供体的质子亲和力的顺序增加时，距离的趋势和偶合常数的迹象很明显，这表明了氢键的性质。所有两键自旋-自旋耦合常数（（2h）J（N-N））为正，并且随着N-N距离的增加而减小。所有单键N-H耦合常数（（1）J（N-H））为负（K-1（N-H）为正）。 （1）J（N-H）与N-H距离和施主N原子的杂化有关。传统氢键的单键（HN）-N -...偶合常数（（1h）J（HN））为正（K-1h（HN）为负），但（1h）J（HN）为负当氢键具有足够的质子共享特性时（1h）J（H-N）改变符号的N-N和（HN）-N -...距离分别约为2.71和1.62埃。对于那些对于EOM-CCSD计算而言太大的复合物，将预测（2h）J（N-N）和（1）J（N-H）的值以及（1h）J（H-N）的符号。

著录项

相似文献

  • 外文文献
  • 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