On the Web edited by
William F. Coleman Wellesley College Wellesley, MA 02481
Reflecting on 103 Months of Featured Molecules William F. Coleman Department of Chemistry, Wellesley College, Wellesley, Massachusetts 02481, United States
[email protected] This is my last column as editor of the JCE Featured Molecules section of the Journal; I would like to take this opportunity to reflect on the impetus for starting the feature, and highlight some of the issues that have been addressed over the years. I suggested the idea for the column to then Journal Editor John Moore in late 2001 or early 2002, and we went live in June of 2002. I wanted to add a third dimension to many of the chemical structures that appeared in the Journal as I firmly believed, and still believe, that structural visualization is crucial to developing as a chemist, or in developing an appreciation for chemistry. Two-dimensional representations, while interesting historically, just fail to promote understanding of a variety of aspects of chemistry to many students in the same way as interactive three-dimensional structures do. At the time we began the column, there were a number of molecule collections available on the Internet, so the first question that needed to be addressed was “why another molecule collection”. My intent was to build a collection for which the organizing theme was providing structures in the context of articles in that issue of the Journal. As time went on I began to think of ways that the molecules that had been chosen could be used in other aspects of the curriculum. In particular, I have enjoyed thinking about those molecules that illustrate specific chemical phenomena, those that might enrich courses for students who are not intending to become chemists, and those that might be used to introduce computational methods to students at the undergraduate level. Chirality is a phenomenon that has shown up on a number of occasions in the featured molecules. Many students have difficulty “seeing” the mirror images of structures in two dimensions. In July of 2005, the featured molecules were the eight stereoisomers of menthol, together with the suggestion that students compute the energies of the various species to verify what they had been told about the energies of enantiomers versus diastereomers (1). In August of 2006, we examined the eight stereoisomers of Ni(en)32þ, including ethylenediamine backbone isomerization (2), and in May 2008, we explored the infrared and vibrational circular dichroism spectra of the enantiomers of 4-benzyl-2-oxazolidinone (3). In those cases where the chiral substance was a drug, we urged students to learn something about the isomeric specificity of the drug application (4). Most of the columns have included molecules that might potentially be of interest to students who are not science majors, molecules that they will encounter in their daily lives (5-8, for example). Additionally, a number of these molecules make interesting research paper assignments for students in various chemistry courses. 1458
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JCE Featured Molecules for December 2010
An interesting application of papers from the Journal is developing new exercises that look at molecules students have previously encountered in a different way. In many instances, this involves adding a computational component to an experiment, or doing that computational activity in a subsequent course. In this issue of the Journal, three papers lend themselves seamlessly to this approach. Lawrence A. Huck and William J. Leigh describe an experiment in which students explore the spectroscopic properties of various potential sunscreen molecules using the results of moderately high-level DFT calculations and the resultant structural parameters and molecular orbitals (9). Those students who then take physical chemistry could be reminded of the experiment, and asked to perform various calculations on the molecules. For example, if they change basis sets, or methods, are the structural results consistent with the arguments they used in their organic chemistry course? This would also be a good example to use when introducing students to the calculation of various forms of spectra. The paper by Pamela P. Vaughan, Michael Cochran, and Nicole Haubrich, on the photochemistry of quinones, could also be easily extended to the physical chemistry course, or to a course in computational chemistry (10). Lastly, the paper by Nicholas A. McGrath, Matthew Brichacek, and Jon T. Njardarson almost begs for a three-dimensional version that brings up the interactive structures when the appropriate square on their diagram is clicked (11). Those authors use the phrase “the beautiful organic architectures of the top-selling pharmaceuticals”, and that pretty well sums up what this column has been about: the beautiful architecture of molecules and how an understanding of that architecture can enhance the understanding of and the predictive power of chemistry (12). Literature Cited 1. Coleman, W. F. J. Chem. Educ. 2005, 82, 1048; DOI: ed082p1048. 2. Coleman, W. F. J. Chem. Educ. 2006, 83, 1248; DOI: ed083p1248. 3. Coleman, W. F. J. Chem. Educ. 2008, 85, 752; DOI: ed085p752. 4. Coleman, W. F. J. Chem. Educ. 2004, 81, 981; DOI: ed081p981. 5. Coleman, W. F. J. Chem. Educ. 2004, 81, 604; DOI: ed081p604. 6. Coleman, W. F. J. Chem. Educ. 2006, 83, 882; DOI: ed083p882. 7. Coleman, W. F. J. Chem. Educ. 2007, 84, 1650; DOI: ed084p1650. 8. Coleman, W. F. J. Chem. Educ. 2010, 87, 760; DOI: ed100494g.
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Vol. 87 No. 12 December 2010 pubs.acs.org/jchemeduc r 2010 American Chemical Society and Division of Chemical Education, Inc. 10.1021/ed1009893 Published on Web 10/19/2010
On the Web 9. Huck, L. A.; Leigh, W. J. J. Chem. Educ. 2010, 87; DOI: 10.1021/ ed1004867. 10. Vaughan, P. P.; Cochran, M.; Haubrich, N. J. Chem. Educ. 2010, 87; DOI: 10.1021/ed1004239. 11. McGrath, N. A.; Brichacek, M.; Njardarson, J. T. J. Chem. Educ. 2010, 87; DOI: 10.1021/ed1003806.
r 2010 American Chemical Society and Division of Chemical Education, Inc.
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12. JCE Featured Molecules from Jun 2002 through Dec 2009 are available at the JCE Digital Library, http://www. jce.divched.org/JCEWWW/Features/MonthlyMolecules/ (accessed Oct 2010). JCE Featured Molecules from Jan 2010 to Nov 2010 are available in the HTML version of each column.
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