In the Classroom edited by
JCE Featured Molecules
William F. Coleman Wellesley College Wellesley, MA 02481
Lubricating Greases June Featured Molecules The Featured Molecules for this month all come from the paper on the chemistry of lubricating grease by Craig Donahue (page 862–869; molecules 1–10, 12–14, 16, 17, 20–22). This paper is a rich source of structural examples ranging from small molecules to metal complexes to polymeric species. Students who are new to structural chemistry might find it useful to compare the structures in the text to their 3-dimensional counterparts to see if they can find instances where the two representations result in different ideas about the structure. They might also examine the 3-dimensional model of molecule 20 and decide what values of x and y were used to construct this.
Molecule 9 provides an opportunity for students in introductory or organic chemistry to speculate on the nonplanar nature of the structure in light of the fact that aniline is planar, while the two phenyl rings in biphenyl are not coplanar. Although all medium and high-level calculations predict a nonplanar structure for 9, the degree of nonplanarity differs, sometimes significantly, from one computational model to another. Fully manipulable (Chime and Jmol) versions of these and other molecules are available at the JCE Digital Library Web site: http://www.JCE.DivCHED.org/JCEWWW/Features/ MonthlyMolecules/2006/Jun
furfural, 1
N-phenyl-1-naphthylamine, 9 N, N´- disalicylidene1,2-diaminopropane, 14
terephthalic acid, 7
JCE Featured Molecules http://www.JCE.DivCHED.org/JCEWWW/Features/MonthlyMolecules
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Journal of Chemical Education
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Vol. 83 No. 6 June 2006
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www.JCE.DivCHED.org
