NMR Determination of Hydrogen Bond Thermodynamics in a Simple Diamide: A Physical Chemistry Experiment

Autor/inn/en	Morton, Janine G.; Joe, Candice L.; Stolla, Massiel C.; Koshland, Sophia R.; Londergan, Casey H.; Schofield, Mark H.
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 Verfügbarkeit
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 + Suchen Sie Ihr Suchwort? Thermodynamik; Chemie; Spektroskopie; Laboruntersuchung; Schülerkritik; Teaching method; Lehrmethode; Unterrichtsmethode; Bildungspraxis; Lehrstrategie; Laboratory work; Laborarbeit
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