Solid State ¹⁹F NMR in ‘Model’ Membrane Systems

Abstract

Solid state NMR techniques can be used to study the behaviour of molecules in membranes and their model systems^1,2,3,4. We used a 4,4-difluoromyristate-D₂O mixture to test the possibilities. The major interactions are the F-F dipolar coupling, the F-H dipolar coupling and the F chemical shift anisotropy. A normal ¹⁹F Free Induction Decay will be featureless and will after fourier transformation lead to a broad resonance signal (fig. 1). It can be shown, however, that a Carr-Purcell-Meiboom-Gill pulse sequence selects the F-F dipolar coupling and fourier transformation of the F.I.D. leads to a so-called Pake doublet spectrum¹ (fig. 1). From the splitting the |S_FF| order parameter of the fluorine pair can be directly determined, according to

$$\Delta = \left| {{S_{FF}}} \right|\Delta \left( {\rm O} \right)\Delta \left( {\rm O} \right) = 16,0 kHz$$