Department of Chemistry, Youngstown State University, Youngstown, Ohio 44555, and Instituto de Química Médica, CSIC, Juan de la Cierva, 3, E-28006 Madrid, Spain.
J Chem Theory Comput. 2008 Jun;4(6):967-73. doi: 10.1021/ct800111j.
Second-order polarization propagator approximation (SOPPA) and equation-of-motion coupled cluster singles and doubles (EOM-CCSD) methods have been employed for the calculation of one-bond spin-spin coupling constants in series of small molecules and ions, and of one- and two-bond coupling constants across X-H···Y hydrogen bonds. For isolated molecules, one-bond SOPPA coupling constants (1)J(X-Y) involving (13)C, (15)N, (17)O, and (19)F have larger absolute values than corresponding EOM-CCSD coupling constants, with the EOM-CCSD values being in significantly better agreement with available experimental data. The difference between SOPPA and EOM-CCSD tends to increase as the number of nonbonding electrons on the coupled atoms increases, and the SOPPA values for O-F coupling are significantly in error. Similarly, the absolute values of SOPPA one-bond coupling constants (1)J(X-H) for the hydrides NH3, H2O, and FH and their protonated and deprotonated ions are greater than EOM-CCSD values, with the largest differences occurring for F-H coupling. One- and two-bond coupling constants (1)J(X-H), (1h)J(H-Y), and (2h)J(X-Y) across X-H···Y hydrogen bonds in neutral, protonated, and deprotonated complexes formed from the hydrides are similar at SOPPA and EOM-CCSD, with the largest differences again found for (1)J(F-H) in complexes with F-H as the proton donor, and (2h)J(F-F) for (FHF)(-). The signs of (1)J(X-H), (1h)J(H-Y), and (2h)J(X-Y) are the same at both levels of theory, as is their variation across the proton-transfer coordinate in F-H···NH3. SOPPA would appear to provide a reliable and more cost-effective alternative approach for computing coupling constants across hydrogen bonds, although couplings involving F may be problematic.
二阶极化传播近似（SOPPA）和运动方程耦合簇单重态和双重态（EOM-CCSD）方法已被用于计算一系列小分子和离子中一键自旋-自旋耦合常数，以及 X-H···Y 氢键中一键和两键耦合常数。对于孤立分子，涉及 (13)C、(15)N、(17)O 和 (19)F 的一键 SOPPA 耦合常数 (1)J(X-Y) 的绝对值大于相应的 EOM-CCSD 耦合常数，EOM-CCSD 值与现有实验数据更吻合。随着耦合原子上非键电子数的增加，SOPPA 和 EOM-CCSD 之间的差异趋于增加，并且 O-F 耦合的 SOPPA 值存在明显误差。同样，NH3、H2O 和 FH 及其质子化和去质子化离子的 SOPPA 一键耦合常数 (1)J(X-H) 的绝对值大于 EOM-CCSD 值，其中 F-H 耦合的差异最大。在由氢化物形成的中性、质子化和去质子化复合物中，X-H···Y 氢键的一键和两键耦合常数 (1)J(X-H)、(1h)J(H-Y) 和 (2h)J(X-Y) 在 SOPPA 和 EOM-CCSD 中相似，最大差异再次出现在作为质子供体的 F-H 复合物中以及 (FHF)(-) 中的 (2h)J(F-F)。(1)J(X-H)、(1h)J(H-Y) 和 (2h)J(X-Y) 的符号在两种理论水平上是相同的，并且在 F-H···NH3 中质子转移坐标上也是如此。SOPPA 似乎为计算氢键中耦合常数提供了一种可靠且更具成本效益的替代方法，尽管涉及 F 的耦合可能存在问题。
