Dipolar filtered magic-sandwich-echoes as a tool for probing molecular motions using time domain NMR.

We present a simple H NMR approach for characterizing intermediate to fast regime molecular motions using H time-domain NMR at low magnetic field. The method is based on a Goldmann Shen dipolar filter (DF) followed by a Mixed Magic Sandwich Echo (MSE). The dipolar filter suppresses the signals arising from molecular segments presenting sub kHz mobility, so only signals from mobile segments are detected.

A double-component Anderson-Weiss approach for describing NMR signals of mobile SIn units: application to constant-time DIPSHIFT experiments.

A composed Gaussian local field is proposed to describe the effect of molecular motions on NMR signals of SIn units (e.g., CHn or NHn), based upon the well-know Anderson-Weiss (AW) approximation.

Avoiding bias effects in NMR experiments for heteronuclear dipole-dipole coupling determinations: principles and application to organic semiconductor materials.

Carbon-proton dipole-dipole couplings between bonded atoms represent a popular probe of molecular dynamics in soft materials or biomolecules. Their site-resolved determination, for example, by using the popular DIPSHIFT experiment, can be challenged by spectral overlap with nonbonded carbon atoms. The problem can be solved by using very short cross-polarization (CP) contact times, however, the measured modulation curves then deviate strongly from the theoretically predicted shape, which is caused by the dependence of the CP efficiency on the orientation of the CH vector, leading to an anisotropic magnetization distribution even for isotropic samples.

Intermediate motions and dipolar couplings as studied by Lee-Goldburg cross-polarization NMR: Hartmann-Hahn matching profiles.

In this article, we evaluate the use of simple Lee-Goldburg cross-polarization (LG-CP) NMR experiments for obtaining quantitative information of molecular motion in the intermediate regime. In particular, we introduce the measurement of Hartmann-Hahn matching profiles for the assessment of heteronuclear dipolar couplings as well as dynamics as a reliable and robust alternative to the more common analysis of build-up curves. We have carried out dynamic spin dynamics simulations in order to test the method's sensitivity to intermediate motion and address its limitations concerning possible experimental imperfections.