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ERIC Number: EJ820781
Record Type: Journal
Publication Date: 2007-Sep
Pages: 3
Abstractor: As Provided
Reference Count: 4
ISBN: N/A
ISSN: ISSN-0021-9584
Determination of the Rotational Barrier for Kinetically Stable Conformational Isomers via NMR and 2D TLC: An Introductory Organic Chemistry Experiment
Rushton, Gregory T.; Burns, William G.; Lavin, Judi M.; Chong, Yong S.; Pellechia, Perry; Shimizu, Ken D.
Journal of Chemical Education, v84 n9 p1499-1501 Sep 2007
An experiment to determine the rotational barrier about a C[subscript aryl]-N[subscript imide] single bond that is suitable for first-semester organic chemistry students is presented. The investigation begins with the one-step synthesis of a N,N'-diaryl naphthalene diimide, which exists as two room temperature-stable atropisomers (syn and anti). The students then estimate the rotational barrier, [Delta]G[double dagger], by following the reequilibration of the two isomers using two-dimensional thin-layer chromatography. A more accurate determination of the rotational barrier is conducted by a [to the first power]H NMR time study. The synthesis, purification, and kinetics experiments can be carried out within two, three-hour laboratory sessions using commercially available reagents and instrumentation found in most undergraduate laboratories. (Contains 2 schemes and 3 figures.)
Division of Chemical Education of the American Chemical Society. Subscription Department, P.O. Box 1267, Bellmawr, NJ 08099-1267. Tel: 800-691-9846; Tel: 856-931-5825; Fax: 856-931-4115; e-mail: jchemed@egpp.com; Web site: http://www.jce.divched.org
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A