Separation of 2H NMR spectra assisted by molecular dynamics in diamagnetic and paramagnetic solids

Abstract

The relaxation-assisted separation method was applied to overlapping 2H nuclear magnetic resonance (NMR) spectra of diamagnetic and paramagnetic solids to separate them based on the different relaxation behaviors caused by molecular motion. Carr–Purcell–Meiboom–Gill sequences for 2H NMR were adopted to build two-dimensional data sets from one-dimensional NMR experiments. For diamagnetic α-glycine, the 2H NMR spectrum collected at 198 K was separated into two components from static –CD2– and dynamic –ND3. In addition, for the paramagnetic Sm(NO3)3·6D2O, the asymmetric 2H NMR spectra obtained at 213 K due to the hyperfine coupling was also separated into two components, which corresponded to coordinated and crystal water molecules undergoing a 180° flip motion with different correlation times.