Use of Heteronuclear Multiple Bond Correlation NMR Spectroscopy to Identify Organic Spectroscopy Unknowns

Sarah Wagner

This project's goal was to develop a Heteronuclear Multiple Bond Correlation (HMBC) nuclear magnetic resonance (NMR) pulse program for SOU's spectroscopy program. HMBC is a two-dimensional NMR technique that has long range chemical shift correlation capabilities used to identify carbons and hydrogens that are separated by up to four bonds. One-dimensional Proton, Carbon-13, and DEPT-135 NMR spectra and 2-dimensional H-H correlation (COSY), Heteronuclear Single Quantum Correlation (HSQC), and HMBC NMR spectra were acquired using a Bruker Avance 400 MHz NMR Spectrometer and processed using MestReNova software. Two different concentrations of 2,4-dichlorotoluene, ρ-Cymene, and allyl phenyl ether were tested and it was determined that the sample concentration had no significant effect on HSQC data whereas higher sample concentrations provided additional correlation peaks in HMBC spectra. It was determined that HSQC resolution was improved when the sample tube was spun at 20 Hz, but spinning did not have a significant effect on HMBC data. The development of the HMBC experiment, while still underway, has provided promising results.