The performance of a spin echo spectrometer which is suitable for chemical exchange studies is described. Using the Carr-Purcell sequence of pulses, proton T₂ values were obtained from two experiments differing only in their method of eliminating accumulated
error in the width of the 180° pulses. The Meiboom-Gill method of phase shifting the r.f. in the first pulse is more flexible in the range of pulse intervals.
Following the theory of Bloom, Reeves and Wells, rate constants describing the exchange process in two molecules were measured from the dependence of T₂ upon the pulse interval. The values of the rate constants for the hindered internal rotation about the N-N bond in N, N-dimethylnitrosamine agree with previous
high resolution studies.
A similar spin echo study has been conducted in order to measure the rates of internal rotation about the C-N bond in N, N-dimethylcarbamyl chloride. The values for the entropy of activation are consistently
low. The possibility of systematic errors in the spin echo method has been investigated.
It is concluded that reported values of rate constants in magnetic resonance should be the result
of a spin echo investigation extending over as wide a temperature range as possible in addition to a high resolution study which involves a complete theoretical line shape fit to the experimental data. / Science, Faculty of / Chemistry, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/36738 |
| Date | January 1966 |
| Creators | Krakower, Earl |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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