Diffusion Coefficient-Formula Weight (D-FW) Analysis of 2H Diffusion-Ordered NMR Spectroscopy (DOSY)

We report extension of the D-FW analysis using referenced H-2 DOSY. This technique was developed in response to limitations due to peak overlay in H-1 DOSY spectra. We find a corresponding linear relationship (R-2 > 0.99) between log D and log FW as the basis of the D-FW analysis. The solution-state structure of THF solvated lithium diisopropyl amide (LDA) in hydrocarbon solvent was chosen to demonstrate the reliability of the methodology. We observe an equilibrium between monosolvated and disolvated dimeric LDA complexes at room temperature. Additionally we demonstrate the application of the H-2 D-FW analysis using a compound with an exchangeable proton that is readily labeled with H-2. Hence, the H-2 DOSY D-FW analysis is shown to provide results consistent with the H-1 DOSY method, thereby greatly extending the applicability of the D-FW analysis.