I'm still looking for additional sources of information, so please contribute
experimental notes, references, or any other info that you wish to provide.
Responses from both academia and industry are encouraged. These responses
and other NMR instructional info are also available through our web page at
http://nmrsg1.chem.indiana.edu/, and I expect that additional info will be
added later. I hope this "NMR in Undergraduate Instruction" web resource
will be helpful for those who incorporate NMR experiments into udergrad
instruction.
Marty Pagel mpagel@indiana.edu --- __o
Department of Chemistry Phone: (812)-855-6492 --- \<,
Indiana University Fax: (812)-855-8300 --- ()/ ()
Bloomington, IN 47405-4001 http://nmrsg1.chem.indiana.edu/~mpagel
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The following are SUMMARIES of responses:
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NMR instruction is part of our analytical, organic, and inorganic,
chemistries, but not physical chemistry. For Jr. year course in applied
spectroscopy for analytical chemists, students are given unknowns to solve.
Organic and inorganic students characterize synthesis products in their labs,
which include NMR spectra.
Jack Martin Miller
e-mail jmiller@sandcastle.cosc.brocku.ca
http://chemiris.labs.brocku.ca/staff/miller/miller.html
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There are a number of viable places for (NMR instruction) and the choice of
an individual department or program will depend on several factors, including
personnel. I strongly believe that chemistry majors should be introduced to
the technique early (i.e., during the second year) but, because our organic
chemists are not enthusiastic about revising their courses to include
practical NMR experiences, a reasonable solution seems to be to provide it
separately but concurrently.
Ellen A. Keiter
cfeak@eiu.edu
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Sophmore qualitative organic chemistry laboratory students and Instrumental
Analysis Laboratory students receive a (NMR) spectrum of their unknown
compound. Spectra for the qualitative analysis course are taken with an
automated sample changer, but advanced undergraduates may acquire their
own spectra. Students enrolled in the Physical Chemistry Laboratory find
the equilibrium constant for a keto-enol tautomerism using NMR. Polymer
Laboratory students find the tacticity of a polymer.
(The students) probably should have the exposure to the instrument, which is
better facilitated by a specialist in NMR. During the 1970's Varian used to
distribute a list of experiments to their customers with a EM390. This list
will get you thinking about a variety of chemical systems and so I think it
is a good place to start.
John West
west@qtp.ufl.edu
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UNM plans to incorporate NMR into
1) freshman honours lab: NMR of water, methanol, and ethanol
2) 2nd semester sophmore organic lab: DEPT of cholesterol acetate
3) Jr level inorganic lab: complex formation
4) upper level organic/inorganic/pchem lab: DEPT + other expts.
5) upper level instrumentation lab
Karen Ann Smith
karenann@unm.edu
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NMR _is_ "multidisciplinary", any way that you look at it. You could even
include NMR in physics, electrical engineering, and even computer science
departments to some extent.
George D. Sukenick, Ph.D.
g-sukenick@ski.mskcc.org
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I posted a query last month for ideas for NMR experiments for undergrads.
Here is a summary of the responses I received. Hope they're helpful
Cathy Lester
Richard Showmaker (rshoe@wwitch.unl.edu) wrote:
We also do the keto-enol expt. Another good one is the determination of the
activation energy of rotation about the amide bode in DMF. You have to have
Variable Temp. to do this experiment, but it REALLY drives home the important
concepts of dynamic NMR, AND kinetics in general.
I tried to find my "canned" experiment, with all of the writeup, and data
processing info in it...but no luck yet.
For now, this is the best I can do:
The methyl resonances of Dimethyl-formamide are two separately resolved
singlets at room temperature due to restricted rotation about the C=N bond.
The two peaks coalesce at around 150 deg. C. For Very slow exchange, the two
methyls (A & B) have two distinct resonances at (vA & vB). In this regime,
the residence lifetimes of the methyls (tA and tB) can be considered to be
infinity on the NMR timescale. As the Temperature rised, and the exchange
rate increases, tA and tB decrease, and the width of the peaks at vA & vB
increase, with the half-width inversly proportional the the lifetimes (tA &
tB). Of course at higher temps (faster rates of exchange) the two lines
coalesce, and eventually the line sharpens to give a single resonance at a
frequency = (vA+vB)/2. At the coalescence temperature the lifetime (t) =
sqrt(2)/pi (vA-vB), where vA and vB are the separate frequences with no
exchange. At this point, the rate constant can be determined, and from that
the activation energy for the exchange process can be derived. I've seen
this done both using C-13 NMR, and proton NMR. I've personally only done it
via proton NMR, but it shouldn't matter.
For a complete writeup of the analysis of the data, and determination of the
activation energy for rotation, check one of the following (I tried to double-
check the references, but both books are checked out of our library right now):
Coton and Jackman, "Dynamic Nuclear Magnetic Resonance Spectroscopy", Academic
Press (1975).
J. Sandstrom, "Dynamic NMR Spectroscopy", Academic Press, (1982).
The titles are VERY similar, but there _are_ actually different books 8-).
I once had a copy of a P-Chem. lab text which had the "canned" experiment;
however, I can't find it, and I can't remember the authors or anything...not
very helpful, I'm afraid.
Michael Mosher (mosherm@platte.unk.edu) wrote:
Another experiment I can think of is: determination of the structure of a
compound based on the J(H-C) values. Run a H-NMR on two very similar compounds
and determine which is which by calculation of the %s character of the C-H
bonds. (%s = J(H-C) * 0.2) (Example compounds: acetone and acetone oxime, or
nitromethane and nitrosomethane)
How about measuring the rotational barrier to binaphthol using VT?
Alan M. Kook (meadhbh@neosoft.com) wrote:
One experiement that we performed at Rice University was part of the
instrumental analysis lab. The students determinationed levels of caffeine
and variuos other components of over-the-counter medications like tylenol
and vanquish. Really interesting results for those consumers who WANT TO KNOW.
(1) Simply grind and suspend the tablet in a 2:1 mixture of CD3OD:CDCl3
(not sure of first solvent)
(2) let filler settle out and run H-1 NMR on supernate. [D1=5 seconds
P1=30 VT=ambi NS=32]
(3) integrate and compare spectra on a light board
The interesting thing about this experiment is that these results can be
compared to HPLC and UV experiments run on the same samples. Keep in mind
that fresh samples must be used (no greater than 8 hours old) for the
analysis since some of the components do degrade quickly.
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A Tecmag upgrade is a popular choice for converting NMR equipment
into teaching instrumentation. Contact Paul J. Kanyha, Tecmag,
Inc., support@tecmag.com, for more info.
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