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2001
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In the Laboratory
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Simple Preparation and NMR Analysis of mer and fac Isomers of Tris(1,1,1-trifluoro-2,4-pentanedionato)cobalt(III). An Experiment for the Inorganic Chemistry Laboratory
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Ashley W. Jensen and Brian A. O'Brien
Department of Chemistry, Gustavus Adolphus College, Saint Peter, MN 56082
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July 2001
Vol. 78 No. 7
p. 954
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| Abstract |
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A one-step procedure for the preparation of tris(1,1,1-trifluoro-2,4-pentanedionato)cobalt(III) from hydrated cobalt(II) carbonate and 10% hydrogen peroxide, in which tert-butyl alcohol is used as a component of the solvent, is described. The procedure is short, simple, and less hazardous than procedures reported in the literature, and the starting materials are readily available and inexpensive. The product is a mixture of mer and fac isomers that can be separated by silica gel chromatography with toluene as the eluent. Thin-layer chromatography is used to obtain a collective class sample of each isomer for 1H, 13C, and 19F NMR analysis. The NMR analyses clearly illustrate the threefold rotational symmetry of the fac isomer and the lack of symmetry of the mer isomer. Detailed NMR data are provided for each isomer.
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| Supplement |
Supplemental material, including notes for the instructor, experimental background and instructions for students, NMR spectra and chemical shift tabulations, and IR spectra, are available.
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 Contents |
JCE2001p0954W.wpd (Word Perfect); JCE2001p0954W_F1.cdx, JCE2001p0954W_F2.cdx (ChemDraw); spectra (folder containing 19 NMR and 3 IR spectra as JPEG files)
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| More Information |
Citation |
Jensen, Ashley W.; O'Brien, Brian A. J. Chem. Educ. 2001 78 954.
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Keywords |
Chromatography; Cobalt; Coordination Chemistry; Inorganic Chemistry; Inorganic Synthesis; Laboratory Instruction; NMR Spectrometry; Stereochemistry
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History |
Created:
Last Updated: |
June 6, 2001
August 31, 2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
2001
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