Single‐crystal ²H NMR of deuterated 1,10‐decanedicarboxylic acid included in hydrogenated urea channels

Abstract

The intergrowth of 1,10-decanedicarboxylic acid and urea give infinite hydrogen-bonded chains of the guest included in the hexagonal urea host. A deuterium high-resolution solid-state NMR study of the selectively deuterated intergrowth compound 1,10-decanedicarboxylic acid/hydrogenated urea at variable temperature in the range 90 ≤ T ≤ 300 K was performed on a single crystal. The analysis of the second moment as a function of temperature is shown to be compatible with the known phase transition occurring near T c = 203 K. Moreover, the spectra indicate that the orientational disorder is strong, and is compared to an axial uniform disorder. For this purpose, the general equation for the second moment of a system with uniform two-dimensional axial orientational disorder is given, and a method to take into account the non-uniform excitation of the pulse sequence is proposed.

Residual orientational disorder of deuterated nonadecane in hydrogenated urea nanotubes: single crystal 2H NMR

“…In particular for organic compounds, deuterium 2 H NMR directly probes the C-D bond orientation and dynamics through the dynamical averaging of the quadrupolar interaction carried by the covalent bond. Single crystal solid-state NMR also offers the unique opportunity to measure the intrinsic orientational disorder [7] from the information contained in spectra acquired at different magnetic field orientations.…”