Bruker Avance 300 MHz NMR Spectrometer

The 2000 award from HHMI included modest funding to facilitate the purchase of a new Bruker Avance 300 MHz NMR spectrometer, which was installed in the Chemistry Department in August 2000. The new NMR has greatly enhanced the Department's infrastructure for teaching and research by undergraduate students. Four instructors have submitted information about the laboratory exercises that students complete with this new instrument.

Christian M. Rojas, Assistant Professor of Chemistry, uses the high-field NMR instrument extensively in both teaching and research. In the Advanced Organic Chemistry teaching laboratory, Rojas's students routinely characterize reaction products by proton and carbon NMR. Rojas's research group uses NMR as the main tool for structure determination in a research program aimed at developing new methodology for the synthesis of nitrogen-containing organic molecules. Access to the high-field NMR instrument was essential to discoveries that led to the recent publication, with undergraduate co-authors, of a paper on metal-catalyzed nitrogen insertion reactions (Organic Letters, 2002, 4, 863-865). The Barnard NMR facility has been a key component in Rojas's ability to offer undergraduate students a productive and challenging research atmosphere.

Ann E. Shinnar, Assistant Professor of Chemistry, uses the high-field NMR instrument with biochemistry majors, both in the biochemical laboratory techniques course and in her independent research projects. In the biochemistry laboratory, students identify simple sugars by analyzing proton and carbon spectra. The biochemistry class investigations have also been expanded to study the kinetics of a- and ß-anomerization, serving as an experiment that reinforces principles of organic and physical chemistry as well. As part of her research program, Shinnar has been interested in identifying isomers of bromotryptophan found in naturally occurring peptides and in elucidating the biochemical role of this unusual amino acid. The availability of this high field NMR spectrometer has made such studies very feasible and has also increased our student competence and confidence in acquiring and interpreting NMR data.

Dina Merrer, Assistant Professor of Chemistry, uses the 300-MHz NMR spectrometer both in teaching and research. In the Advanced Physical Chemistry teaching laboratory, her students use proton NMR to quantify intramolecular hydrogen-bonding complexes of phenol molecules. Students use the NMR chemical shift data in conjunction with custom software to deduce the average number of phenol molecules in a typical hydrogen-bonded complex. In so doing, they learn that the NMR can be used for quantitative measurements important to physical and physical organic chemists. This serves as an excellent complement to their previous use of the NMR in Prof. Rojas' Advanced Organic Laboratory course for molecular structure determination.

Linda Doerrer, Assistant Professor of Chemistry, uses the high-field NMR instrument extensively in both teaching and research. Doerrer's research group uses NMR as supplementary tool in their studies of transition-metal phenolate complexes. Students use proton, carbon, fluorine, and occasionally thallium and phosphorous NMR spectra. Reaction purity and composition are assessed in this manner. Some of these data were presented at the American Chemical Society meeting in Orlando, FL (April 6-10, 2002).