Solid-state Nuclear Magnetic Resonance of Polymorphic Materials
Nuclear Magnetic Resonance and Electron Spin Resonance Spectroscopy
Published Online: 15 MAR 2011
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Vogt, F. G. 2011. Solid-state Nuclear Magnetic Resonance of Polymorphic Materials. Encyclopedia of Analytical Chemistry. .
- Published Online: 15 MAR 2011
Solid-state nuclear magnetic resonance (SSNMR) spectroscopy is a powerful analytical technique for the analysis of polymorphs, which are molecules that exist in different crystalline phases. In this review, applications of SSNMR to polymorphism and related phenomena in a variety of chemical systems are discussed, including pharmaceuticals, food materials, explosives, dyes and pigments, biomolecules, inorganic materials, and organometallic compounds. The advantages of SSNMR are highlighted in relation to other analytical techniques, such as diffraction methods. The SSNMR techniques commonly used to analyze these systems and probe aspects of their polymorphic structure are reviewed, and illustrative examples from each class are given. In recent years, increasingly sophisticated SSNMR methods have been applied to the analysis of polymorphism, including 2-D correlation methods, methods that measure chemical shift tensors, methods that extract quadrupolar parameters at high static field strengths, and computational methods that assist in interpreting and understanding the experimental data in relation to crystal structure. Multicomponent crystals including salts, solvates, and cocrystals also display polymorphism, and are often included with polymorphs in investigations of supramolecular chemistry and crystal engineering. The relationship between crystalline and amorphous materials is also discussed to emphasize the applicability of the analytical technique and the complementary information often obtained. Finally, the importance of SSNMR within multidisciplinary studies of polymorphism using other techniques is emphasized.