Diffusion constant DOSY

Self-diffusion coefficients have been obtained by diffusion-ordered spectroscopy (DOSY [24,25]). For the [C2CiIm]Cl/AlCl3 system, the diffusion constants for all [CjCjIm] proton resonances were identical. A linear relationship between diffusion constants and conductivihes of the melts demonstrated the fact that the transport properties are determined by the molar quantities (and not by the properties of the individual ions). 

A complete NMR approach has been employed to evaluate the complexation process of catechin A with p-CD and synthetic analogues.125 The analysis of the variation of the proton chemical shifts indicated the formation of a 1 1 stoichiometric complex. 2D-ROESY provided detailed spatial information of the complex while the binding constants were obtained by using diffusion-order spectroscopy (DOSY) techniques. 

The association constants for CyD complexes with chiral guests are generally different and mostly quantitatively determined by the chemical shift titration experiments. However, as mentioned above, other NMR parameters, such as relaxation rates [10, 70] or self-diffusion coefficients, may also be used. Both those parameters were successfully applied for the enantiodifferentiation and determination of association constants in complexes of the trifluoroacetate salts of the enantiomers of amphetamine, ephedrine, and propranolol with 2,6-di-O-dodecyl-a-CyD and its p analogue [71]. The DOSY technique was employed for the determination of diffusion coefficients of enantiomers of cyclohexanone derivatives complexed with a-, j8-and y-CyDs as well as with their per-O-methylated analogues [72]. 

---