The 1H, 19F and 13C spectra have been obtained of a sample of peri-difluoronaphthalene dissolved in the nematic liquid crystalline solvent ZLI 1695. The 13C satellite spectra from the six, single-13C isotopomers at natural abundance in both the 1H and 19F spectra were identified and analysed to yield a set of residual total, anisotropic spin–spin couplings, Tij. This was achieved by first obtaining residual 13C–19F and 13C–1H couplings from a proton-encoded, 13C detected, local field 2D spectrum. The 45 values of THH, THF and TCH were used to obtain the structure of the molecule, and then to estimate whether there is a significant contribution from the component along the magnetic field, Janiso ijzz , of the anisotropic, electron-mediated, spin–spin coupling tensors for 13C–19F and 19F–19F pairs. It is found that there is strong evidence for a significant contribution of Janiso FFzz to TFF but not for the 13C–19F pairs.
The inderect through-space F-F coupling in peri-difluoronaphthalene:is it anisotropic?
DE LUCA, Giuseppina;
2008-01-01
Abstract
The 1H, 19F and 13C spectra have been obtained of a sample of peri-difluoronaphthalene dissolved in the nematic liquid crystalline solvent ZLI 1695. The 13C satellite spectra from the six, single-13C isotopomers at natural abundance in both the 1H and 19F spectra were identified and analysed to yield a set of residual total, anisotropic spin–spin couplings, Tij. This was achieved by first obtaining residual 13C–19F and 13C–1H couplings from a proton-encoded, 13C detected, local field 2D spectrum. The 45 values of THH, THF and TCH were used to obtain the structure of the molecule, and then to estimate whether there is a significant contribution from the component along the magnetic field, Janiso ijzz , of the anisotropic, electron-mediated, spin–spin coupling tensors for 13C–19F and 19F–19F pairs. It is found that there is strong evidence for a significant contribution of Janiso FFzz to TFF but not for the 13C–19F pairs.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
