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Autor/inn/en | Morton, Janine G.; Joe, Candice L.; Stolla, Massiel C.; Koshland, Sophia R.; Londergan, Casey H.; Schofield, Mark H. |
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Titel | NMR Determination of Hydrogen Bond Thermodynamics in a Simple Diamide: A Physical Chemistry Experiment |
Quelle | In: Journal of Chemical Education, 92 (2015) 6, S.1086-1090 (5 Seiten)Infoseite zur Zeitschrift
PDF als Volltext |
Sprache | englisch |
Dokumenttyp | gedruckt; online; Zeitschriftenaufsatz |
ISSN | 0021-9584 |
DOI | 10.1021/ed400644a |
Schlagwörter | Thermodynamics; Chemistry; Spectroscopy; Science Experiments; Synthesis; Molecular Structure; Undergraduate Students; Laboratory Procedures; Student Reaction; Teaching Methods; Hands on Science; Educational Practices; Educational Strategies; Laboratory Experiments |
Abstract | Variable temperature NMR spectroscopy is used to determine the ?H° and ?S° of hydrogen bond formation in a simple diamide. In this two- or three-day experiment, students synthesize N,N'-dimethylmalonamide, dimethylsuccinamide, dimethylglutaramide, or dimethyladipamide from methylamine and the corresponding diester (typically in 50% recrystallized yield) and record NMR spectra at temperatures between 200 and 313 K. Solutions of N-methylacetamide in concentrations between 1.00 mM and 13.1 M (neat) are prepared and their NMR spectra recorded to determine the chemical shift of the amide proton in the hydrogen-bonded (d[subscript B]) and nonbonded (d[subscript N]) limits. By using these data, the equilibrium constants, ?H°, and ?S° for the conversion of an open-chain diamide to a cyclic structure with an intramolecular hydrogen bond are determined. (As Provided). |
Anmerkungen | Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail: eic@jce.acs.org; Web site: http://pubs.acs.org/jchemeduc |
Erfasst von | ERIC (Education Resources Information Center), Washington, DC |
Update | 2020/1/01 |