Applications of a Benchtop NMR Spectrometer in an
Undergraduate Chemistry Laboratory
A. Jonathan Singh,1 Almas Zayya,1 Bertram Manz,2 John L. Spencer,1 Peter T. Northcote,1 Robin Dykstra2 and Andrew Coy2
1School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand2Magritek Ltd., 32 Salamanca Rd, Wellington, New ZealandIntroduction

The Magritek Spinsolve benchtop NMR
spectrometer.

Teaching NMR spectroscopy in undergraduate chemistry programmes is fast
becoming a more routine practice – particularly with the advent of benchtop
NMR spectrometers. Unlike traditional superconducting spectrometers, this newclass of NMR spectrometer is sufficiently robust, safe, and stable to be deployed
directly in a typical chemistry laboratory and simple enough to be easily operated
by students. We have been using the Spinsolve benchtop NMR spectrometer,
manufactured by the New Zealand company Magritek, over the last six months
and are exploring avenues in which to integrate the use of this instrument and its
range of 1D- and 2D-NMR experiments into our undergraduate chemistryteaching programmes.

The Magritek Spinsolve benchtop NMRspectrometer in action.

First Year: 2D-NMR as a Teaching Tool

Second Year: Reaction Monitoring

Interpretation of 1H NMR spectra is often the most difficult aspect for students to learn,
especially when factors such as J-coupling, peak overlap and second-order effects
dominate the spectrum. By introducing the 2D J-resolved experiment at an earlier stageof teaching, students are able to observe these effects independently by placing Jcoupling on to the second dimension. As demonstrated with ibuprofen (1), the precise
chemical shifts and multiplicities of all protons (with the exception of H-8) can beassigned. The presence of equidistant satellites are indicative of through-bond coupling.

The ability to monitor chemical reactions in real-time provides valuable information
about synthetic processes. For example, acetophenone (2) and anisaldehyde (3) arereacted in ethanolic KOH to produce 4-methoxychalcone (4). By performing thereaction in the NMR tube, students can determine when the reaction is sufficiently
complete before proceeding with work-up and purification. Furthermore, thegeometry about the alkene can be determined by analyzing the 2D J-resolved
spectrum of the purified compound.

Third Year: Advanced Experiments and Interpretation
NMR spectroscopy is an important tool in the understanding of chemical principles. Starting with thep-complex ferrocene (5), one cyclopentadienyl anion is substituted for a benzene molecule to form
cationic species 6. Nucleophilic attack on the benzene ring in compound 6 using LiAlH4 affords theneutral h5-C6H7 complex 7. The analogous reaction with LiAlD4 shows that the attack occurs on theexo face of the benzene ring to form complex 8. Analysis of 1H and COSY spectra acquired on theSpinsolve allows detailed structural information to be at hand within minutes of sample preparation.

Future Directions
We have demonstrated how the incorporation of a benchtop NMR
spectrometer can enhance both the teaching and learning
experience in the laboratory. The ease of use and accessibility of
the Spinsolve means we can approach existing experiments in adifferent manner, introduce other experiments which employ NMR
methods (e.g. kinetic studies), or utilize other NMR-active nuclei
such as 13C and 19F.