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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Predicted signs of one-bond spin-spin coupling constants ((1h)J(H-Y)) across X-H-Y hydrogen bonds for complexes with Y=N-15, O-17, and F-19
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Predicted signs of one-bond spin-spin coupling constants ((1h)J(H-Y)) across X-H-Y hydrogen bonds for complexes with Y=N-15, O-17, and F-19

机译：Y = N-15，O-17和F-19配合物的X-H-Y氢键上单键自旋-自旋偶联常数的预测符号（（1h）J（H-Y））

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摘要

Ab initio equation-of-motion coupled cluster (EOM-CCSD) calculations have been performed on a set of 44 complexes to obtain one-bond H-Y spin-spin coupling constants ((1h)J(H-Y)) across X-H-Y hydrogen bonds, with Y as the second-period elements N-15, O-17, and F-19. For complexes with traditional hydrogen bonds, the reduced Fermi-contact terms and the reduced one-bond spin-spin coupling constants (K-1h(H-Y)) are negative. Since K-1(X-H) has been shown previously to be positive, a change of sign of these two coupling constants must occur along the proton-transfer coordinate. For complexes with symmetric X-H-X hydrogen bonds, the two reduced X-H coupling constants are equal and positive at equilibrium. For complexes stabilized by hydrogen bonds that have some proton-shared character, both K-1h(H-Y) and K-1(X-H) are also positive. The signs of all three reduced coupling constants (K-1h(H-Y), K-2h(X-Y), and K-1(X-H)) that can arise between pairs of hydrogen-bonded atoms are interpreted in terms of the nuclear magnetic resonance triplet wave function model (NMRTWM). Determination of the signs of (KH)-K-1h-Y and K-1(X-H) could be useful for confirming the presence or absence of a proton-shared hydrogen bond.
机译：已经对一组44个配合物进行了从头算运动方程耦合簇（EOM-CCSD）计算，以获得XHY氢键上的单键HY自旋-自旋耦合常数（（1h）J（HY））， Y作为第二阶段元素N-15，O-17和F-19。对于具有传统氢键的配合物，降低的费米接触项和降低的单键自旋-自旋耦合常数（K-1h（H-Y））为负。由于先前已证明K-1（X-H）为正，因此这两个耦合常数的符号必须沿质子传递坐标发生变化。对于具有对称X-H-X氢键的配合物，两个降低的X-H耦合常数相等，并且在平衡时为正。对于具有质子共享特性的氢键稳定的配合物，K-1h（H-Y）和K-1（X-H）均为正。氢键原子对之间可能出现的所有三个降低的偶合常数（K-1h（HY），K-2h（XY）和K-1（XH））的符号都是根据核磁共振来解释的三重波函数模型（NMRTWM）。确定（KH）-K-1h-Y和K-1（X-H）的征兆可用于确认是否存在质子共享的氢键。

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