Systematic Comparison of Second-Order Polarization Propagator Approximation (SOPPA) and Equation-of-Motion Coupled Cluster Singles and Doubles (EOM-CCSD) Spin−Spin Coupling Constants for Molecules with C, N, and O Double and Triple Bonds and Selected F-Substituted Derivatives

Abstract

Ab initio EOM-CCSD and SOPPA calculations with the Ahlrichs (qzp,qz2p) basis set have been carried out to evaluate one-, two-, and three-bond spin-spin coupling constants for molecules HmXYHn and HmXYHn for X, Y = (13)C, (15)N, and (17)O, and selected (19)F-substituted derivatives. In the great majority of cases, EOM-CCSD one-bond C-C, C-N, C-O, C-F, N-N, N-O, and N-F coupling constants and three-bond F-F coupling constants are smaller in absolute value than the corresponding SOPPA coupling constants, with the EOM-CCSD values in better agreement with experimental data. SOPPA tends to significantly overestimate the absolute values of large one- and three-bond couplings involving fluorine. The majority of two-bond SOPPA coupling constants are in better agreement with experiment than EOM-CCSD, although differences between EOM-CCSD and experimental values are not dramatic. A statistical analysis of thirty EOM-CCSD and SOPPA coupling constants versus experimental coupling constants demonstrates that better agreement with experiment is found when EOM-CCSD is the computational method.

Optimized basis sets for the calculation of indirect nuclear spin-spin coupling constants involving the atoms B, Al, Si, P, and Cl

“…PSO and SD, terms, which dominate the total coupling. This behavior is quite typical for couplings between atoms with more than one lone-pair 135,160,172, 215,216,244,245 . The PSO term is thus the largest contribution in ClF and is more than six times as large as the FC term.…”

B−Hb←:X (X= N, O, P, S, F, Cl, Br) interactions: A density functional study

“…NMR data are very responsive to the influence of the chemical environment around the molecule and therefore provides useful structural information. Suitability of theoretical and computational methods in this respect has been widely explored for studying different molecular systems . The difference of the residing charges, Δ q (Δ q = charge on H b in the complex—charge on H b in free DB) are also informative in predicting the nature of interaction between the two moieties, the calculated Δ q values obtained at ωB97X‐D/6–311++G(2df,2p) level of theory are provided in Table .…”

Do corresponding coupling constants in hydrogen-bonded homo- and hetero-chiral dimers differ?

“…The EOM-CCSD method with the Ahlrichs (qzp,qz2p) basis set has been shown to yield coupling constants in good agreement with experimental values for molecules. [19][20][21][22] Its application to hydrogen-bonded complexes has provided insight into experimentally determined coupling constants, 23 and the predicted relationship between 2h J(N-N) and the N-N distance for N-HÁÁÁN hydrogen bonds 24 has been verified experimentally. 25 Finally, the computed signs and magnitudes of 2h J(X-Y), 1h J(H-Y), and 1 J(X-H) for X-HÁÁÁY hydrogen bonds have been used successfully to characterize hydrogen-bond type.…”