Long-lived nuclear spin states in rapidly rotating CH2D groups.
Although monodeuterated methyl groups support proton long-lived states, hindering of the methyl rotation limits the singlet relaxation time. We demonstrate an experimental case in which the rapid rotation of the CH2D group extends the singlet lifetime but does not quench the chemical shift difference between the CH2D protons, induced by the chiral environment. Proton singlet order is accessed using Spin-Lock Induced Crossing (SLIC) experiments, showing that the singlet relaxation time TSis over 2min, exceeding the longitudinal relaxation time T1by a factor of more than 10. This result shows that proton singlet states may be accessible and long-lived in rapidly rotating CH2D groups.
School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom.
Stuart J
SJ
Elliott
School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom.
Lynda J
LJ
Brown
Institut de Chimie des Substances Naturelles, CNRS UPR2301, Univ. Paris-Sud, Université Paris-Saclay, 91190 Gif-sur-Yvette, France.
Jean-Nicolas
JN
Dumez
School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom. Electronic address: mhl@soton.ac.uk.
Malcolm H
MH
Levitt
Long-lived states; Methyl group; Rotamer; Singlet state