Inquiry-Based IR-Spectroscopy Activity Using iSpartan or Spartan for

Activity Cite This: J. Chem. Educ. XXXX, XXX, XXX−XXX

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Inquiry-Based IR-Spectroscopy Activity Using iSpartan or Spartan for Introductory-Organic-Chemistry Students Amy M. Balija*,† and Layne A. Morsch‡ †

Radford University, P.O. Box 6949, Radford, Virginia 24142, United States University of IllinoisSpringfield, Springfield, Illinois 62703, United States

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J. Chem. Educ. Downloaded from pubs.acs.org by YORK UNIV on 03/25/19. For personal use only.

S Supporting Information *

ABSTRACT: An inquiry-based activity is described in which organic-chemistry students explore how IR radiation impacts functional-group-bond movements. Through the iSpartan and Spartan apps, students calculate the IR spectra for select organic compounds and manipulate the resulting 3D models and IR spectra to visualize bond vibrations. After developing an IR-frequency chart on the basis of these observations, the students analyze spectral data for the presence of functional groups. The results showed that students successfully prepared the chart and analyzed IR-spectral data without previous experience with IR spectroscopy or instructor intervention. Student responses to the inquiry-based learning activity were favorable. This activity was implemented at three academic institutions over a 4 year period and is an attractive approach for students to explore IR spectroscopy in a nonthreatening environment. KEYWORDS: Organic Chemistry, Second-Year Undergraduate, Computer-Based Learning, Hands-On Learning/Manipulatives, Inquiry-Based/Discovery Learning, IR Spectroscopy

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R spectroscopy is a fundamental concept in introductory organic-chemistry courses that reinforces concepts such as structure, bonding, functional groups, and electromagnetic radiation. Besides being essential to a student’s comprehension of chemistry, IR spectroscopy is a component of healthprofessional-program admissions exams as well as a topic in upper-level chemistry classes.1 Educators have integrated apps in their classrooms to provide an active learning environment.2−5 Karatjas reported using the iSpartan app in his course to introduce 1H NMR, 13C NMR, and IR spectroscopy to organic-chemistry students.6 Although students benefit from these demonstrations, an inquiry-based approach would allow students to investigate spectral data independently and develop their own conclusions.7 Herein, a learning activity for organic-chemistry students is outlined in which iSpartan or Spartan is used to introduce IR spectroscopy. Students develop IR-absorption ranges on the basis of observed molecular vibrations and apply their knowledge to determine functional-group absorption bands in actual spectra. This activity can be introduced in lecture, although the laboratory period allows additional time for students to examine the vibrations. It can serve also as a supplement for an introductory IR-spectroscopy wet-lab experiment.

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(2) to obtain calculated IR-spectral data, (3) to determine the peaks in the IR spectra for specific functional groups, (4) to prepare a chart demonstrating where molecular vibrations for several functional groups appear in an IR spectrum, and (5) to analyze several IR spectra using the previously prepared chart. The pedagogical effectiveness of the activity was determined through student surveys and postactivity worksheets. Student Demographics

Over 4 years, 141 heterogeneous students from Fordham University, 64 students from Radford University, and 70 students from the University of IllinoisSpringfield (UIS) completed this activity. Chemistry and biology majors were enrolled in laboratory sections of 16−22 students. Not all institutions were involved in this learning activity at the same time. Additional academic-institution demographics can be found in the Supporting Information (p S16). iSpartan and Spartan Student Editions

The iSpartan app for mobile devices was employed at Fordham University and UIS.8 A molecular-modeling program, iSpartan allows users to prepare 2D sketches and convert them into 3D models. IR spectra are generated from a database of 6000

INQUIRY-BASED APPROACH

Learning Objectives

Received: June 18, 2018 Revised: March 4, 2019

The learning objectives for the activity were (1) to draw various organic structures in iSpartan or Spartan, © XXXX American Chemical Society and Division of Chemical Education, Inc.

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DOI: 10.1021/acs.jchemed.8b00456 J. Chem. Educ. XXXX, XXX, XXX−XXX

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compounds. At Radford University, the learning activity employed the Spartan Student Edition for desktop computers. In Spartan, IR spectra were calculated using density-functionaltheory calculations. With either app version, the user hovers the cursor over an absorption band to visualize the bond vibration in the 3D model. The results obtained with either app were similar.

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HAZARDS There are no hazards associated with this learning activity. LEARNING ACTIVITY At Fordham, the in-class IR-spectroscopy activity was presented to students midway through their first semester of the organic-chemistry laboratory. Students were familiar with organic structure and bonding but had no reading assignments or lectures on IR spectroscopy prior to starting the learning activity. This course was independent of the organic-chemistry lecture, which covered IR spectroscopy after the iSpartan activity. The learning activity utilizing the iSpartan app was performed during a 4 h laboratory, although most students completed the activity in 2.5 h. Organic functional groups and how IR radiation affects bond vibrational energies was introduced through a 50 min lecture held 1−9 days prior to a student’s laboratory section. At the beginning of the lab period, students observed a 10−15 min demonstration on the iSpartan program, including how to draw compounds, search for calculated IR values, and analyze the resulting spectral data. Students formed groups of 2−4, and each group was given a datasheet and an iPad tablet with the iSpartan program previously installed (Supporting Information, pp S5−S9). On this datasheet, eight functional-group categories were listed: alkenes, alkynes−nitriles, alcohols, amines (1° and 2°), carbonyls, carboxylic acids, amides, and aldehydes. Also, sp3, sp2, and sp C−H bonds were examined. Each category listed two or three different organic compounds. Students drew the 2D structure of each given compound in iSpartan and obtained its IR spectrum, which appeared below a 3D model of the compound. Students investigated the absorption bands by dragging a yellow line across the IR spectrum and observing which bonds vibrated in the 3D model. At specific points, bonds moved in the 3D model, and a wavenumber appeared beneath the spectrum, indicating an absorption value. Using this process, students completed the datasheets by writing the IR-absorption wavenumbers corresponding to that functional group (Figure 1). After viewing several spectra of compounds containing the same functional group, students determined the general range of wavenumbers characteristic for that functional group. The students then prepared their own molecular-vibrations chart by plotting the absorption ranges on an IR spectrum (Figure 1). Most computational IRabsorption values were similar to the actual data. Absorption values for the carbonyls listed on the datasheet were up to 76 cm−1 off from experimental values, and the calculated value for the O−H stretch of 1-butanol was 307 cm−1 higher than the experimental value. These discrepancies should be highlighted to students. Nonetheless, absorbances calculated by iSpartan were accurate enough to allow introductory students to examine how covalent bonds absorb IR light differently. The absorption values did not hinder a student’s evaluation of actual IR spectra, as described below.

Figure 1. (Top) Portion of a datasheet containing organic compounds categorized by functional groups, the answers obtained using iSpartan, and the range of wavenumbers the students obtained. (Bottom) Example IR-absorption chart based upon the datasheet. The wavenumber ranges shown are representations and do not reflect the actual IR-absorption-value ranges that the students obtained.

The student groups completed postactivity worksheets identifying the functional groups present in four IR spectra utilizing only the IR data table they prepared.9 To differentiate between functional groups with two distinctive IR absorbances, such as carboxylic acid derivatives and aldehydes, two spaces were placed next to the compound name. Students wrote down both values and then were guided via a worksheet question to learn how to differentiate between these functional groups. The worksheets were graded and used to assess students’ understanding of IR spectroscopy. Performance depended on the quality of the datasheet prepared and on the ability of the student to interpret IR spectra. Minor modifications of this activity were performed at the other academic institutions (Supporting Information, pp S15−S16).

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LEARNING-ACTIVITY EVALUATION The usefulness of this activity was examined through student responses, student-prepared IR-absorption charts, and answers on a postactivity worksheet. Only 11% of the students selfidentified having moderate, high, or complete knowledge of IR spectroscopy prior to the activity, irrespective of the academic institution. On the basis of 211 student evaluations, 72% of Fordham students and 31% of UIS students would recommend or highly recommend the learning activity. The lower value at UIS may be attributable to the reduced amount of instruction time dedicated to using the app. Positive comments regarding the learning activity included, “Great experiment, it was fun, engaging and I learned a lot that I don’t think I would have without iSpartan”, “This program was amazing! I really loved B

DOI: 10.1021/acs.jchemed.8b00456 J. Chem. Educ. XXXX, XXX, XXX−XXX

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it! Made the information easier to understand!”, and “I liked being able to manipulate the 3D structures of the molecules and observe the different stretching at different wavelengths. The visual made learning the concept much easier.” Most of the negative comments centered on the app: “Drawing the molecules was kind of confusing at first on the app”, and “It was somewhat difficult to differentiate between the types of C−H movements vs double and triple bonds.” Students reported enjoying manipulating the IR spectrum to visualize bond movements. Although the comments were positive concerning the learning activity, 59% of Fordham students and 32% of UIS students thought they had learned most or all of the knowledge concerning IR spectroscopy. These lower numbers may be due to students being accustomed to a lecture format, rather than being active participants.10,11 Although the integration of technology as an alternative method is innovative, students can struggle adapting it to a learning situation.12 Though students experienced 3 h of data analysis, additional practice is needed to correctly analyze IR spectra. A separate assessment was based upon how many functional groups the students correctly assigned in the postactivity worksheet (Supporting Information, p S8). At Fordham, 95% of the students correctly assigned at least three out of four given IR spectra, whereas at Radford, 79% of students identified at least three out of four IR spectra correctly. All students at Fordham and Radford accurately prepared the IRabsorption chart. Student postactivity reports were graded promptly and returned, allowing students to view their mistakes and ask their instructor for clarification. At UIS, IR analysis was reinforced in lab following the iSpartan activity. During the next lab period, students were provided IR review problems that required them to identify functional groups present or absent in provided spectra (Supporting Information, pp S25−S29). In a later experiment, students determined the identities of unknowns using spectroscopic techniques. As part of the analysis, students determined the identity of the functional group on the basis of the IR spectrum. Each student correctly identified the functional groups present or absent in the IR of their unknown 86% of the time. A similar activity was not performed at Fordham University because the IR instrument was not available for student use.

Furthermore, students are exposed to modern computational programs, a requirement for ACS-certified degree programs.

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CONCLUSIONS The use of mobile devices in teaching chemistry is becoming increasingly common.14−16 Mobile apps, smart phones, and tablets are integrated into the collection or analysis of laboratory data.17,18 In this inquiry-based learning activity, organic-chemistry students experienced a stepwise approach to IR spectroscopy. As active participants, the students learned at their own speed in a 3 or 4 h laboratory setting. This activity is an attractive way to engage students in a fundamental technique while exploiting technology. The learning activity provides educators a supplemental approach to introducing IR spectroscopy in a less-formal environment, but it does not detract from a wet-lab experience.

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ASSOCIATED CONTENT

* Supporting Information S

The Supporting Information is available on the ACS Publications website at DOI: 10.1021/acs.jchemed.8b00456. Student IR-spectroscopy instructions, data sheet, worksheet, answer key, student questionnaire, additional assessment data, author comments, and IR-assignment postlearning activity (PDF, DOCX)

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Amy M. Balija: 0000-0003-1205-2580 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS A.M.B. would like to acknowledge Shahrokh Saba, James Ciaccio, Peter Corfield, Fordham University CHEM 2531 and 2541 students, and Radford University CHEM 302 students. L.A.M. would like to thank the CHE 268 students from the University of IllinoisSpringfield.

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DISCUSSION In the inquiry-based approach to IR spectroscopy published by Bennett and Forster,13 students better understood spectral interpretation when they constructed their own IR-absorptioncorrelation table from spectral data. In our inquiry-based learning activity, students also analyzed spectral data by independently constructing an independent IR-absorptionband table. This activity has the added advantage of combining inquiry-based learning with structure visualization. For college students who are computer savvy, technology can be an attractive learning tool. This inquiry-based activity provides an alternative platform to introduce IR spectroscopy. Through an interactive hands-on approach, students investigate the IR bands for specific functional groups and develop their own absorption charts. This style is different from traditional lectures or online videos that only demonstrate vibrations. Although the absorption ranges may be narrow, this activity provides a successful experience to begin understanding IR-spectroscopy analysis.

REFERENCES

(1) Chemical and Physical Foundations of Biological Systems Section: Content Category 4D. AAMC. https://students-residents. aamc.org/applying-medical-school/article/mcat-2015-contentcategory-4d/ (accessed March 2019). (2) Libman, D.; Huang, L. Chemistry on the Go: Review of Chemistry Apps on Smartphones. J. Chem. Educ. 2013, 90, 320−325. (3) Shea, K. M. Beyond Clickers, Next Generation Classroom Response Systems for Organic Chemistry. J. Chem. Educ. 2016, 93, 971−974. (4) Househnecht, J. B. Just-In-Time Teaching Organic Chemistry with iPad Tablets. In The Flipped Classroom Vol. 2: Results from Practice; Muzyka, J. L., Luker, C. S., Eds.; ACS Symposium Series 1228; American Chemical Society: Washington, DC, 2016; pp 81− 92. (5) Morsch, L. A. Flipped Teaching in Organic Chemistry with iPad Tablets. In The Flipped Classroom Vol. 1: Background and Challenges; Muzyka, J. L., Luker, C. S., Eds.; ACS Symposium 1223; American Chemical Society: Washington, DC, 2016; pp 73−92. (6) Karatjas, A. G. Use of iSpartan in Teaching Organic Spectroscopy. J. Chem. Educ. 2014, 91, 937−938.

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(7) Center for Curriculum Development. Doing Science: The Process of Science Inquiry; NIH Publication No. 05-5564; National Institutes of Health, 2005. https://science.education.nih.gov/supplements/ Process%20of%20Scietific%20Inquiry.pdf (accessed March 2019). (8) iSpartan and Spartan. Wavefunction, Inc. https://www.wavefun. com (accessed March 2019). (9) Spectral Database for Organic Compounds SDBS, 2018. National Institute of Advanced Industrial Science and Technology (AIST), Japan. http://sdbs.db.aist.go.jp/sdbs/cgi-bin/cre_index.cgi (accessed March 2019). (10) Eison, J. University of South Florida, Tampa, FL. Using Active Learning Instructional Strategies to Create Excitement and Enhance Learning. Unpublished work, 2010. (11) Deters, K. M. Student Opinions Regarding Inquiry-Based Labs. J. Chem. Educ. 2005, 82, 1178−1180. (12) Diemer, T. T.; Fernandez, E.; Streepy, J. W. Student Perceptions of Classroom Engagement and Learning Using iPads. J. Teach. Learn. Technol. 2012, 1, 13−25. (13) Bennett, J.; Forster, T. IR Cards: Inquiry Based Introduction to IR Spectroscopy. J. Chem. Educ. 2010, 87, 73−77. (14) Williams, A. J.; Pence, H. E. Smart Phones: A Powerful Tool in the Chemistry Classroom. J. Chem. Educ. 2011, 88, 683−686. (15) Morsch, L. A.; Lewis, M. Engaging Organic Chemistry Students Using ChemDraw for iPad. J. Chem. Educ. 2015, 92, 1402−1405. (16) Oliver-Hoyo, M.; Babilonia-Rosa, M. A. Promotion of Spatial Skills in Chemistry and Biochemistry Education at the College Level. J. Chem. Educ. 2017, 94, 996−1006. (17) Schwartz, P. M.; Lepore, D. M.; Morneau, B. N.; Barratt, C. Demonstrating Optical Activity Using an iPad. J. Chem. Educ. 2011, 88, 1692−1693. (18) Grasse, E. K.; Torcasio, M. H.; Smith, A. W. Teaching UV-Vis Spectroscopy with a 3D-Printable Smartphone Spectrophotometer. J. Chem. Educ. 2016, 93, 146−151.

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DOI: 10.1021/acs.jchemed.8b00456 J. Chem. Educ. XXXX, XXX, XXX−XXX