Fluorine-19 NMR Spectroscopy

Different distribution of fluorinated anesthetics and nonanesthetics in model membrane: a 19F NMR study

“…The spectral assignment for isoflurane has been well documented (Dubois and Evers, 1992; Mills et al, 1987; in Fig. 1 were based on theoretical consideration of throughbond shielding and through-space deshielding to the 19F nuclei by the Cl electron clouds (Cavalli, 1976;Feeney et al, 1966;Williamson and Braman, 1967) and were confirmed by the ratio of peak integration for the trans and cis forms of F6 and by 19F homonuclear decoupling spectroscopy. The same number of peaks, with a similar spectral pattern, was found for fully dissolved F3, F6, and F8 in water.…”

Special Topics

“…Direct, one-bond couplings are found to be negative in those molecules for which they have been determined. Accumulation of fluorines tends to decrease the magnitude of the coupling (entries 1-6), but accumulation of protons has even more effect (7)(8)(9)(10). Couplings to trigonal carbons (entries 11 and 12) are comparable to tetrahedral couplings, while those of aromatic carbons (entries 17-24) are somewhat reduced and show at most a weak dependence on the electronegativity of para substituents.…”

“…1 ) Accumulation of halogen atoms on the same carbon also results in marked deshielding (entries [6][7][8][9]. Most of the generalizations that describe relative shielding in hydrocarbon groups 30 CF 3 CF 2 (2<) CF 2 (3() CF 2 (4) CF 2 (3) CF 2 (2) CF 3 F (4) 31 32 33 CF 3 CF 2 CF 2(2) CF 3 34 CF 2 -CF 2 35 Cvclo -C 6 have no applicability to fluorocarbon chains.…”

“…They also exhibit very strong geometrical dependencies, which can upset this correlation. Vicinal and geminal ^F^H couplings for a representative group of substituted alkanes are given in Table 9.3 (entries [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Geminal couplings are all in the range of ca.…”

Biological Magnetic Resonance

“…A number of summaries of fluorine NMR spectroscopy have appeared (Mooney and Winson, 1968;Jones and Mooney, 1970;Fields, 1972Fields, , 1977Barlow, 1971, 1974;Phillips, 1974;Cavalli, 1976) as well as compilations of reported fluorine chemical shifts (Dungan and Van Wazur, 1970;Emsley and Phillips, 1971). A useful discussion of experimental considerations in executing Fourier transform FMR experiments with fluorinecontaining biological systems has also appeared (Sykes and Hull, 1978).…”