Determination of molecular torsion angles using nuclear singlet relaxation

Abstract

The exponential relaxation time constant, TS , of a nuclear singlet state is influenced by the proximity of neighboring NMR-active nuclei. For methylene groups in particular this dependence is much stronger than the case for other NMR relaxation constants, including the "conventional" relaxation time constant, T1 , of the longitudinal magnetization. This sensitivity provides a new route for determining torsional angles plus other molecular structural details in the isotropic solution phase. © 2010 American Chemical Society.