Jeong, Keunhong, Sein Min, Heelim Chae, and Sung Keon Namgoong. “Monitoring of Hydrogenation by Benchtop NMR with Parahydrogen-Induced Polarization.” Magnetic Resonance in Chemistry, August 29, 2018.
Reaction monitoring using nuclear magnetic resonance (NMR) spectroscopy is a powerful tool that provides detailed information on the characteristics and mechanism of the reaction. Although highfield NMR provides more accurate and abundant data, which can be explained in terms of Boltzmann factors, benchtop NMR is commonly used because of its low cost and simple maintenance. Therefore, hyperpolarization of the sample in benchtop NMR is a suitable protocol for real-time reaction monitoring. Herein, the principle-based experimental setup, integrating the reaction monitoring system in a 60-MHz benchtop NMR instrument with a parahydrogen-induced polarization (PHIP) system, is used. Enhanced signals by the ALTADENA mechanism were obtained after PHIP on styrene, and reasonable kinetic data were collected, supporting the known reactivity of Wilkinson’s catalyst. These results should provide a foundation for future applications of NMR-based reaction monitoring systems utilizing hyperpolarization.