provocativelopinion Whether Organic Qual Will Wither? Herman E. Zieger Brooklyn College, CUNY, Brooklyn, NY 11210 I n a recent Provocative Opinion article entitled 'W(h)ither Organic Qual?' ( I ) , J. W. Zubrick reports that his students were correctly identifying organic unknowns a t a higher rate since last September because they had access to FTIR with a built-in data base of standard spectra for organic compounds. Consequently, students were short-circuitine the hard work of intemretine the IR s ~ e c tra themselvegand were identifying unknowns by spee'tral matchine. Thus. there was no need to diaenose the functional &oup(s) i n their unknowns and towconfirmthose functional groups with wet chemical tests. Because he defines the goal of Organic Qua1 as the identifling of unknowns, he wonders whether we should keep on teaching the subject. Do we teach i t because it is useful or because we've always taught it? As a teacher of organic Qualitative Analysis for the past 25 years (21, I have lived through the evolution of organic structure determination by wet chemical test methods through modern spectrometric identification of unknown organic mmpounds. I have always believed that the purDose of the third semester of organic chemistrv laboratow work was to introduce studentito the techniques and operations that are workaday practice in research laboratories. As a corollary to this basic belief I have placed a premium on encouraging a student to work independently, but check frequently with the instructor as to the proper interpretation of all data in the same manner that research co-workers consult their mentors or supervisors on their progress. I have never defined the purpose of the course as correctly identifying the structure of the unknowns. In fact one of the things I require in a written reoort is a list of alternative structures that fit some but not all of the spectral, chemical, or physical properties and how these alternative structures are eliminated from cousideration. There should exist a much more important pedagogic purpose to Organic Qual than training a student how to use a standard range of laboratory equipment items or do a routine list of tests or synthetic experiments or even just correctly identify unknowns. It would seem to me that education a t this level should have as its goal the effort to train students to think independently ahout choosing experiments in a logical and systematic way to solve prohlems. By asking the student to interpret the IR spectrum for you after it has been obtained under your eyes and not in some remote instrument lab where a computer data
230
Journal of Chemical Education
base or a n Aldrich Standard Soectra Cataloe is available for comparison or matchmg p&poses, yougain a much better insight into vour students abilitv. So the solution to this problem is to prevent the use of c~mputerdata bases or to circumvent them bv choosine unknowns not included or to run the lab under test condiiions such that spectrum matching is ~revented.If the student does not receive trainingfro& the instructor in how to interpret IR (and NMH, spectra, how will he do it on the examinations? Indeed, how will he interpret the spectrum of a new compound never previously synthesized or isolated from nature when he meets it in the laboratory? The reason that students need to be trained pro~erlva t interpreting spertra on monofunctional and difu&onal compounds is that in the real world they will be encountering genuine unknowns and polyfunctional compounds that not only are not listed in computer data bases but because of special stereochemical circ&stances or stereoelectronic properties often exhibit unusual IR absorption frequencies or NMR chemical shift values. If trainine in the obtainine and intemretine of IR spectra were intended to be for class of te'chnici&s who'are to be em~lovedin an IR analvtical lab where numerous routine iie&ifications of variety compounds were to be done as expeditiously as possible, then one might actually wish to include learning how to match spectra. But the majority of college students are entitled to an education experience in which the interpretation of the IR spectrum is only one of the components in their study of the physical, chemical, and spectral properties of several classes of compounds. The use of unknowns merely ensures that each student is working on a compound that is different from the one his neighbor is studying at the moment. In conclusion. each instructor will have to mnfront the issuc of unknown identification by spectra comparison with data bases and establish around rules for evaluating student progress in laboratorywork that places less emphasis on getting the right answer and more on the quality of the purification of the sample and the synthesis of derivatives and their purification as well as the considerationof alternative possible structures for the unknown.
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Literature Cited 1. Zubrick, J. W.J Chem. Ed=. 1992,69,387. 2. Department of Chemistry. B m k l p CoUem ofthe City University &New York.
