Related Experiment Video
Updated: May 17, 2026

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
Nonexponential solid state 1H and 19F spin-lattice relaxation, single-crystal X-ray diffraction, and
Donald P Fahey1, William G Dougherty, W Scott Kassel
1Department of Physics, Bryn Mawr College, Pennsylvania 19010-2899, United States.
Abstract:
We investigate the relationship between intramolecular rotational dynamics and molecular and crystal structure in 4,4'-dimethoxyoctafluorobiphenyl. The techniques are electronic structure calculations, X-ray diffractometry, and (1)H and (19)F solid state nuclear magnetic resonance relaxation. We compute and measure barriers for coupled methyl group rotation and methoxy group libration. We compare the structure and the structure-motion relationship in 4,4'-dimethoxyoctafluorobiphenyl with the structure and the structure-motion relationship in related compounds in order to observe trends concerning the competition between intramolecular and intermolecular interactions. The (1)H spin-lattice relaxation is nonexponential in both the high-temperature short-correlation time limit and in the low-temperature long-correlation time limit, albeit for different reasons. The (19)F spin-lattice relaxation is nonexponential at low temperatures and it is exponential at high temperatures.
Related Concept Videos
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
Spin–Spin Coupling Constant: Overview
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
NMR Spectroscopy: Spin–Spin Coupling
