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In the Laboratory
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Photochemical Dimerization of Dibenzylideneacetone. A Convenient Exercise in [2+2] Cycloaddition Using Chemical Ionization Mass Spectrometry
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G. Nageswara Rao, Chelli Janardhana, V. Ramanathan, T. Rajesh, and P. Harish Kumar
Department of Chemistry, Sri Sathya Sai Institute of Higher Learning, Prashanthi Nilayam – 515 134, Andhrapradesh, India
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November 2006
Vol. 83 No. 11
p. 1667
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| Abstract |
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Photochemical [2+2] cycloaddition reactions are geometrically feasible and give rise to four membered rings. We outline a simple laboratory procedure for the photochemical dimerization of dibenzylideneacetone, a dienone, that can be easily prepared in the undergraduate laboratory. The dimerization is confirmed by chemical ionization mass spectrometry, and other spectroscopic techniques are used to establish the structure of the product. A second species can be isolated from the reaction. This is a trimer and is the result of three [2+2] cycloadditions of the dienone.
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| Supplement |
Instructions for the students, notes for the instructor, and details of the chromatographic separation of the dimer A and trimer B are available.
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| More Information |
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Citation |
Rao, G. Nageswara; Janardhana, Chelli; Ramanathan, V.; Rajesh, T.; Kumar, P. Harish. J. Chem. Educ. 2006 83 1667.
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Keywords |
Aldehydes / Ketones; Alkenes; Chromatography; Hands-On Learning / Manipulatives; IR Spectroscopy; Laboratory Instruction; Mass Spectrometry; NMR Spectroscopy; Organic Chemistry; Photochemistry; Second-Year Undergraduate; Thin Layer Chromatography; Upper-Division Undergraduate
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History |
Created:
Last Updated: |
9/19/2006
9/20/2006
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 Caution! | | Experiments, laboratory exercises, lecture demonstrations, and other descriptions of the use of chemicals, apparatus, instruments, computers, and computer interfaces are presented in the Journal of Chemical Education as illustrative of new or improved ideas or concepts in chemistry instruction and are directed at qualified teachers. Although every effort is made to assure and encourage safe practices and safe use of chemicals, the Journal of Chemical Education cannot assume responsibility for uses made of its published materials. Many chemicals are hazardous. Precautions for the safe use of hazardous chemicals and directions for their proper disposal are described in the Material Safety Data Sheets and on the labels. We strongly urge all those planning to use materials from our pages to make choices and to develop procedures for laboratory and classroom safety in accordance with local needs and situations. |
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