Abstract
The through-space NMR spin-spin coupling mechanism between 19F nuclei was investigated at the coupled perturbed density functional level using a BLYP(60:40) functional and a large basis set. Through-space coupling decays exponentially with the distance R(F,F) and is strongly angular dependent. The lp(σ) and lp(σ)-lp(σ) contributions to the FC term are larger than the corresponding lp(π ip) contributions. The passive lp(π) contributions are responsible for 10% of the FC mechanism. The PSO term is not negligible. In 1,8-difluoronaphthalene, the FC term of 56 Hz results from through-space coupling (75 Hz) and σ through-bond coupling (-19 Hz). The magnitude of through-space coupling can be predicted with a suitable model.
Original language | English |
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Pages (from-to) | 5-13 |
Number of pages | 9 |
Journal | Chemical Physics Letters |
Volume | 394 |
Issue number | 1-3 |
Early online date | 15 Jul 2004 |
DOIs | |
Publication status | Published - 11 Aug 2004 |
Funding
Calculations were done on the supercomputers of the Nationellt Superdatorcentrum (NSC), Linköping, Sweden. D.C. thanks the NSC for a generous allotment of computer time. J.G. thanks Carl Tryggers Stiftelse for financial support.
Keywords
- through-space coupling
- NMR through-space coupling
- FC term