Spectroscopy of Fluorinated Monosaccharides

Because of these great improvements, all magnetic nuclei can now be used in n.m.r. analysis of fluorinated monosaccharides, including H, C, N, and F. Table I gives the relevant, spectroscopic data for these nuclei. 

Nuclei Spin Natural abundance Sensitivity Relative Absolute Range Gyromagnetic ratio Frequency  

An empirical approach for estimating geminal coupling-constants has been described for a limited class of compounds. Irrespective of whether fluorine is axially or equatorially oriented, an increase ( 3 Hz) in V results upon changing the vicinal substituent from the axial (a) to the equatorial (e) orientation, whereas changing the fluorine atom from equatorial to axial has little or no effect. An exception to the latter occurs in cases where the substituent is a ring-oxygen or -sulfur atom. 

Vicinal Coupling, V ( H, F). The signs of vicinal couplings were found to be absolutely positive, and their angular dependence parallels that of proton-proton coupling-constants, - ranging between 0 and 

This coupling shows the same angular dependences as the corresponding fluorine-proton or proton-proton counterpart, thus permitting the development of Karplus-type relationships the sign was assumed to be positive.  

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N.M.R. SPECTROSCOPY OF FLUORINATED MONOSACCHARIDES 93 Table VIII (continued)... 

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