Related Experiment Video
Updated: Aug 9, 2026

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
Solid-state photodimerization kinetics of alpha-trans-cinnamic acid to alpha-truxillic acid studied via solid-state
Marko Bertmer1, Ryan C Nieuwendaal, Alexander B Barnes
1Department of Chemistry and Center for Materials Innovation, Washington University, St. Louis, Missouri 63130, USA.
Abstract:
The present work focuses on the topochemical photoconversion process in which alpha-trans-cinnamic acid becomes alpha-truxillic acid. This solid-state [2 + 2] cycloaddition reaction has previously been studied with X-ray diffraction, atomic force microscopy, and vibrational spectroscopy. However structural and kinetic details about the reaction are still debated. We present results from (13)C cross-polarization magic angle spinning solid-state NMR experiments that suggest that the Johnson, Mehl, Avrami, and Kolmogorov model of phase transformation kinetics can be applied to this system. The model elucidates parameters of the reaction, such as the nucleation rate, diffusion rate, and dimensionality of the reaction. From our data, it is concluded that this reaction follows one-dimensional growth with a decreasing nucleation rate.
Related Concept Videos
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
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.
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
UV–Vis Spectroscopy: Woodward–Fieser Rules
Raman Spectroscopy: Overview
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and the...
