A relativistic DFT study of one-bond fluorine-X indirect spin–spin coupling tensors

Abstract

The relativistic zeroth-order regular approximation (ZORA) DFT method was employed to investigate indirect spin-spin coupling tensors involving fluorine, (1)J(X, F). The relative contributions of the mechanisms contributing to (1)J(X, F) are discussed, with special attention paid to the magnitude and origin of the anisotropy in this tensor, DeltaJ. This quantum chemical study demonstrates that, for the systems investigated, the ZORA-DFT method reproduces the magnitude of (1)J(X, F)(iso) and indicates that DeltaJ(X, F) is of the same order of magnitude as (1)J(X, F)(iso). Several examples are provided that demonstrate the importance of considering contributions of DeltaJ to the experimental measurement of effective dipolar coupling constants, R(eff). Given the difficulties with determining DeltaJ experimentally and the promising computational results, we suggest that the quantum chemical calculation of (1)J(X, F) be used as a complementary tool to aid in the analysis of data from NMR experiments designed to measure dipolar coupling constants.

Computational 19F NMR. 1. General features

“…Some early computational work (aimed at benchmarking and validation) included F 2 as test molecule, which proved to be challenging [26][27][28]. Interest in modeling 19 F shifts has steadily continued, and several papers have appeared in the last decade aimed at general structural issues, solution chemistry and physical organic chemistry, [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] solid-state issues (especially the prediction of chemical shift tensors), [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64] J-couplings [65][66][67][68][69][70][71][72]…”

Quantum chemical calculations of77Se and125Te nuclear magnetic resonance spectral parameters and their structural applications

“…[372] This result can be compared with another value of approximately −1525.3 Hz, obtained using the pure relativistic ZORA-DFT(LDA)/TZ2P approach by Feindel and Wasylishen. [367] The latter deviates from the experiment by slightly more than 104 Hz.…”

“…Feindel and Wasylishen [367] have calculated the 1 J ( 77 Se, 19 F) iso in SeF 6 molecule using quasi-relativistic ZORA-DFT(LDA)/TZ2P approach. This was evaluated as approximately −1525.3 Hz, which deviates from the experiment by about 104.4 Hz, being (−)1420.9 Hz.…”

“…For example, first ZORA‐DFT calculation of 1 J (Te,F) SSCC in TeF 6 molecule has been performed by Feindel and Wasylishen. [ 367 ] One of their objectives was to study the potential of the ZORA‐DFT method in application to the calculation of the one‐bond isotropic SSCCs involving fluorine nucleus. In general, for the considered group‐16 hexafluorides, the agreement with the experiment may be regarded as acceptable, but not for the TeF 6 molecule.…”

First example of the correlated calculation of the one‐bond tellurium–carbon spin–spin coupling constants: Relativistic effects, vibrational corrections, and solvent effects

“…Moreover, for today a lot of experimental SSCCs involving tellurium have not been confirmed computationally and a thorough theoretical investigation of the quantitative tendencies of tellurium SSCCs has not been carried out in a systematic way. However, recent breakthrough in the area of computer engineering has advanced a considerable progress in using some high‐level theoretical approaches to calculate J ‐tensors, among those involving tellurium atoms …”