Barbara Colonna

SENIOR LECTURER, ORGANIC CHEMISTRY

Ph.D., University of Birmingham/UCLA,
Supramolecular Organic Chemistry 1999

Email: b.colonna@miami.edu

Typical Course Offerings Include:
Organic Chemistry I & II (CHM 201 & 202)
Honors Organic Chemistry (CHM 202)

Area of Interest:
Regulation of carbohydrate based derivatives for drug delivery systems.

In teaching organic chemistry, a notoriously difficult discipline, I strive to promote in the students a critical sense and the ability to think for themselves. It is essential to me that they not just learn to reproduce what is in the textbook, but that they also develop the ability to make connections and create a live knowledge of how organic chemistry, a surprisingly creative discipline, works. I do this by linking abstract examples to the historical vicissitudes of their discovery, my own personal scholarly experience (I mention for instance how John W. Conforth, a Nobel Laureate I studied with, helped me to set up my first independent research reaction), and their own lives. This comes up, for instance, when talking about chirality. I mention how there are some drugs on the market (Albuterol and Zopenex are an example) that are based on the same molecule but are more or less effective according to whether they are racemic mixtures or enantiomerically pure.

Here are some concrete techniques I use to help students master the complexity of my discipline. Although the examples I give are related to organic chemistry, I believe all these techniques can benefit teachers in any discipline.

1) After many years of teaching organic chemistry, I have realized that students tend to get into a rut in applying information presented in the textbook. Necessarily, even the best textbooks cover material in a linear, sequential way. In organic chemistry, this happens through the organization of the material according to functional group reactivity. However, a specific type of reaction, for instance oxidation, can be applied to different functional groups. When students see a given reaction applied to one functional group, they have a hard time seeing how that very same reaction works similarly with other functional groups. Even though the textbook does repeat the same reaction with different functional groups, students cannot easily retrieve this information and make the necessary connections. So, for instance, they will tend to think that oxidation is what happens in chapter 1, even though it is repeated by the textbook in subsequent chapters. In this way, they will associate oxidation with a given functional group, without realizing that the very same process applies in many other cases described elsewhere in the book.

The best way for the students to make the necessary leap is to encourage them to assemble specific material presented in different chapters in one large sheet, so that, for instance, they will have all possible instances of oxidation available to them together. I devote a lot of class time to explaining how to create this sheet, in which otherwise dispersed information is connected in a web-like way. Once they create this crucial studying tool, I ask that they constantly update it with the new information that gets presented in the course.

I think of this, not as a different way of presenting chemistry, but as a study tool. Students who are trained to think across the book succeed better in exams and, also, are better able to understand the big picture.

2) Although it is fashionable nowadays to use overhead transparencies and fancy PowerPoint animations in the classroom, I have learned that these technique are sometimes more aesthetically pleasing that pedagogically useful. If I put a whole complex reaction mechanism on a transparency, students will learn less than if I walk them through the reaction one step at a time on the board or on superimposed transparency sheets in which each step is presented separately. This allows them both to follow the sequence more closely and, also, since I call on them to help with each step, to become involved in producing it. I also try to change the techniques I use in different class meetings or even during the same class so as to keep them attentive and awake. I’ll move constantly from the board to a transparency to class discussion to make the class as lively as possible.

3) At the beginning of class, I typically put what I plan to do in class that day on the board. If I plan to do a set of reactions, for instance electrophilic addition to alkenes, I put a general reaction with hypothetical atoms on the board (something like CH 2=C(CH 3)H + X-Y, where X is an electrophile and Y is a nucleophile). After that, I write all the possible examples of that reaction with real molecules. Then, I start explaining each one of them, working out the peculiarities of each instance. As I go through them I check them off the board, so the students have a clear sense of the progress we are making. At the end, I leave the last two reactions unexplained and assign them as a homework to the students. On the following class meeting, I go over what they did at home and clarify points they may be unclear about. This way, I briefly reprise the concepts explained in the previous class and make the students an active part of the learning process.

4) One key element of my pedagogy is office meetings. I encourage students to come to my office hours with questions, but I don’t deal with them one at a time. Instead, I ask them to come to my office as a group (if the space is not enough we go outside), so they have a chance to hear the questions of their fellow students and learn from my explanations. Usually, I take this opportunity to let them answer their classmates’ doubts, if they are able to do so.

5) Finally, before the final exam I give an out-of-hour review session in which I only work out problems (instead of lecturing). After the exam, I promptly schedule another session in which I go over the test giving the solution to and explaining the problems I assigned. Most everyone attends both. The students regularly tell me that both sessions are very helpful to them.

SELECTED PUBLICATIONS

Carano, M; Colonna, B; Echegoyen, L; Le Derf, F; Levillain, E; Salle, M: "Aqueous reference electrodes are unstable in organic media containing metal ions: a cautionary note to the supramolecular chemistry community": Supramol. Chem.200315, 83–85

Ballardini, R; Colonna, B; Gandolfi, MT; Kalovidouris, SA; Orzel, L; Raymo, FM; Stoddart, JF: "Porphyrin-containing glycodendrimers": Eur. J. Org. Chem.2003, 288–294

Trippe, G; Ocafrain, M; Besbes, M; Monroche, V; Lyskawa, J; Le Derf, F; Salle, M; Becher, J; Colonna, B; Echegoyen, L: "Self-assembled monolayers of a tetrathiafulvalene-based redox-switchable ligand": New J. Chem. 200226, 1320–1323

Herranz, MA; Colonna, B; Echegoyen, L: "Metal ion recognition and molecular templating in self-assembled monolayers of cyclic and acyclic polyethers": Proc. Natl. Acad. Sci. USA200299, 5040–5047

Ashton, PR; Balzani, V; Clemente-Leon, M; Colonna, B; Credi, A; Jayaraman, N; Raymo, FM; Stoddart, JF; Venturi, M: "Ferrocene-containing carbohydrate dendrimers": CHem. Eur. J.20028, 673–684

Colonna, B; Echegoyen, L: "Templated SAMs for metal ion recognition": Chem. Commun.2001, 1104–1105

Colonna, B; Harding, VD; Nepogodiev, SA; Raymo, FM; Spencer, N; Stoddart, JF: "Synthetic carbohydrate dendrimers - Part 7 - Synthesis of oligosaccharide dendrimers": Chem. Eur. J.19984, 1244–1254

Colonna, B; Menzer, S; Raymo, FM; Stoddart, JF; Williams, DJ: "Noncovalent synthesis of donor/acceptor stacks": Tetrahedron Lett.199839, 5155–5158