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In the Laboratory
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JCE Featured Molecules
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Molecular Models of Ruthenium(II) Organometallic Complexes
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William F. Coleman
Department of Chemistry, Wellesley College, Wellesley, MA 02481
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March 2007
Vol. 84 No. 3
p. 492
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The featured molecules for this month come from the paper by Ozerov, Fafard, and Hoffman in which they study the reactions of a number of “piano stool” complexes of ruthenium(II). The synthesis of compound 2a offers students an alternative to the preparation of ferrocene if they are only preparing one metal-arene complex, and the use of the (p-cymene)RuCl2 dimer as a starting material introduces them to a compound that has become an important starting material for the synthesis of a number of ruthenium catalysts. Two structures are found for the dimer in the gas phase, one with the chlorides cis to one another and a more stable form with the chlorides trans. DFT calculations using the LanL2MB basis set and the B3LYP functional in Gaussian 03 (1) show the trans form to be about 90 kJ/mol more stable than the cis form. The structures of the trans form of the dimer and of compound 2a are presented in 2 format—with bonds from the ruthenium ion to all of the carbons in the aryl ring and with a single line to a ghost atom in the center of the ring. These are the two common ways of representing such structures, but students should be made aware that the overall coordination about the ruthenium in both the dimer and in compound 2a is octahedral, and should look at the structures to convince themselves of that fact.
It is also instructive to look at compound 2a, and the other piano stool complexes that are made in the paper, to see how deceptive representation of the triphenylphosphine moiety as PR3 is in terms of the stereochemical bulk of that group.
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| di-μ-chlorobis[(p-cymene)chlororuthenium(II)] (cis dimer) |
Fully manipulable (Chime and Jmol) versions of Ruthenium(II) Organometallic Complexes are available at the JCE Digital Library Web site.
Literature Cited
- Gaussian 03, Revision C.02, M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomery, Jr., T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D. Daniels, M. C. Strain, O. Farkas, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong, C. Gonzalez, and J. A. Pople, Gaussian, Inc., Wallingford CT, 2004.
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| More Information |
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Citation |
Coleman, William F. J. Chem. Educ. 2007 84 492.
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Keywords |
Computer-Based Learning; Kinetics; Organometallics; Thermodynamics; Upper-Division Undergraduate
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History |
Created:
Last Updated: |
2/1/2007
2/22/2007
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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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