Title: Aromatic Boron Wheels with More than One Carbon Atom in the Center: C<sub>2</sub>B<sub>8</sub>, C<sub>3</sub>B<sub>9</sub><sup>3+</sup>, and C<sub>5</sub>B<sub>11</sub><sup>+</sup>
Abstract: Angewandte Chemie International EditionVolume 44, Issue 7 p. 1078-1082 Communication Aromatic Boron Wheels with More than One Carbon Atom in the Center: C2B8, C3B93+, and C5B11+† Stefan Erhardt Dipl.-Chem., Stefan Erhardt Dipl.-Chem. Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35039 Marburg, Germany, Fax: (+49) 6421-282-5566Search for more papers by this authorGernot Frenking Prof. Dr., Gernot Frenking Prof. Dr. [email protected] Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35039 Marburg, Germany, Fax: (+49) 6421-282-5566Search for more papers by this authorZhongfang Chen Dr., Zhongfang Chen Dr. Department of Chemistry, University of Georgia, Athens, GA, USA, Fax: (+1) 706-542-7514Search for more papers by this authorPaul von Ragué Schleyer Prof., Paul von Ragué Schleyer Prof. [email protected] Department of Chemistry, University of Georgia, Athens, GA, USA, Fax: (+1) 706-542-7514Search for more papers by this author Stefan Erhardt Dipl.-Chem., Stefan Erhardt Dipl.-Chem. Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35039 Marburg, Germany, Fax: (+49) 6421-282-5566Search for more papers by this authorGernot Frenking Prof. Dr., Gernot Frenking Prof. Dr. [email protected] Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35039 Marburg, Germany, Fax: (+49) 6421-282-5566Search for more papers by this authorZhongfang Chen Dr., Zhongfang Chen Dr. Department of Chemistry, University of Georgia, Athens, GA, USA, Fax: (+1) 706-542-7514Search for more papers by this authorPaul von Ragué Schleyer Prof., Paul von Ragué Schleyer Prof. [email protected] Department of Chemistry, University of Georgia, Athens, GA, USA, Fax: (+1) 706-542-7514Search for more papers by this author First published: 21 January 2005 https://doi.org/10.1002/anie.200461970Citations: 97 † The research at Marburg has been supported by the Deutsche Forschungsgemeinschaft. The work at Georgia was supported by National Science Foundation Grant CHE-0209857. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Graphical Abstract Computational exploration of carboranes of formula CnBmq+ reveals that more than one hypercoordinated carbon atom can be enclosed by a peripheral ring comprising a suitable number of boron atoms. The C2B8, C3B93+, and C5B11+ species (the LUMO of the latter is shown) are stabilized by substantial Hückel π aromaticity. Furthermore, multicenter σ bonding helps bind the inner carbon units to the boron perimeters, though they can freely rotate relative to one another. Supporting Information Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2005/z461970_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. References 1For recent reviews, see 1aK. Sorger, P. v. R. Schleyer, THEOCHEM 1995, 338, 317–346; 1bD. Röttger, G. Erker, Angew. Chem. 1997, 109, 840–856; Angew. Chem. Int. Ed. Engl. 1997, 36, 812–827; 1cL. Radom, D. R. Rasmussen, Pure Appl. Chem. 1998, 70, 1977–1984; 1dW. Siebert, A. Gunale, Chem. Soc. Rev. 1999, 28, 367–371; 1eR. Choukroun, P. Cassoux, Acc. Chem. Res. 1999, 32, 494–502; 1fV. I. Minkin, R. M. Minyaev, R. 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Frunzke, G. Frenking, Angew. Chem. 2003, 115, 1341–1345; Angew. Chem. Int. Ed. 2003, 42, 1303–1306. 5We calculated neutral C5B10 (among other CnBmq+ species) because the total number of valence electrons (50) and the expected number of π electrons (10) leaves 40 valence electrons for the σ framework. For a cyclic species of C5B10, one would need 20 electrons for ten BB bonds and ten electrons for five CC bonds, thus leaving ten electrons for carbon–boron bonding. The latter ten electrons could be used for five CB2 moieties, that is, there would be five three-center two-electron bonds for the bonding between the carbon and boron cycles. Planar (D5h) C5B10 is a transition state; the vectors of the imaginary frequency point to an out-of-plane distortion. 6The geometries have been optimized at the B3LYP level by using 6-311+G(2df) basis sets. The nature of the stationary points was examined by calculating the Hessian matrices at the B3LYP/6-311+G(2df) level. All the calculations have been carried out with the Gaussian 03 program.[7] 7Gaussian 03 (Revision A.1), 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, 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. 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Schleyer, C. Corminboeuf, G. Seifert, R. Reviakine, J. Weber, J. Phys. Chem. A 2003, 107, 6470–6475. The MO–NICS analyses were at the GIAO B3LYP/6-31G(d) level. The total NICS values calculated at this level are comparable to those calculated at GIAO-B3LYP/6-311+G(2df) level (See the Supporting Information). 13P. v. R. Schleyer, A. I. Boldyrev, J. Chem. Soc. Chem. Commun. 1991, 1536–1538. 14 14aX. Li, L. S. Wang, A. I. Boldyrev, J. Simons, J. Am. Chem. Soc. 1999, 121, 6033–6038; 14bL. S. Wang, A. I. Boldyrev, X. Li, J. Simons, J. Am. Chem. Soc. 2000, 122, 7681–7687; 14cX. Li, H. F. Zhang, L. S. Wang, G. D. Geske, A. I. Boldyrev, Angew. Chem. 2000, 112, 3776–3779; Angew. Chem. Int. Ed. 2000, 39, 3630–3633. Citing Literature Volume44, Issue7February 4, 2005Pages 1078-1082 ReferencesRelatedInformation
Publication Year: 2005
Publication Date: 2005-01-21
Language: en
Type: article
Indexed In: ['crossref']
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