An Alternative Method of Learning Characteristic Spectroscopic Signals Students find learning characteristic IR absorption frequencies and NMR chemical shifts rather difficult using the method found in popular undergraduate textbooks: memorizing columns of data correlating structures and shifts of frequencies. The tables look nothing like the spectra seen in problems; the numbers mean little to a beginning student. The alternative method described here has helped me and should make learning spectroscopic signals easier for other students. In this method, the students convert the tables of data to a form resembling the spectra seen in problems and learn while doina it. Each student is aiven a sheet of NMR and IR chart DaDer. The student then colors in the sienal .. ranw for the drsired functional groups, adding addltmnal functional groups as they are studied thrwghout the year. Overlapping signals can be seen easily by slacking Ih~sirnalr~gion.;upwnrd along the ordmate. A varicts~~fculors may I* used to indlrnte the diff~rentgroups; they a h inureate rhe chnrts' wsual appeal.
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Charts similar to these can be found in many texts. Those charts are complicated, however, and contain many functional groups the undergraduate organic student would not encounter. The proposed exercise has several advantages: the charts contain onlv the functional erouvs .. . the student needs: these are added onlvas thevare studied in lecture: the student adds each n r w signal range t o t h r charts. learning its posltion imtnrdiately; the charr p p e r s o r e t h r sanwo~wsused in pnhlcms nnd in the Iahoratory. With thcie c h a m the wldcnr sees nor only the numerical values bur also the area on the chart5 where the signals appear; the interpreution of spectra from characteristic signals i5 strarghtforward and r~mplified.
J. Keith Butler Memphis State UniverJity Memphis. TN 38152
Volume 61
Number 6
August 1984
703
