Spherical Homoaromaticity

✍ Scribed by Zhongfang Chen; Haijun Jiao; Andreas Hirsch; Paul von Ragué Schleyer

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 158 KB
• Volume: 114
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/1521-3757(20021115)114:22<4485::aid-ange4485>3.0.co;2-w

✦ Synopsis

Since aromaticity [1] is not confined only to planar rings but also exists in three-dimensional systems, [2] the same should be true of homoaromaticity. [3±5] Although the 4Nþ2 H¸ckel electron-counting rule is defined for planar systems it has been applied to rationalize the properties of three-dimensional homoaromatic systems. [5] Recently, the 2(Nþ1) 2 counterpart of the H¸ckel rule [6] has been extended successfully [2e, 7, 8] to the aromaticity of three-dimensional delocalized systems with near spherical geometries: fullerenes, hydrogen and lithium clusters, as well as some well-known closoboranes and Zintl ions. It was found that the highest degree of aromaticity can only be achieved in systems with fully filled valence shells. We now present new conceptual applications of this electron-counting rule to three-dimensional homoaromatic systems with cubane, dodecahedrane, and adamantane frameworks. Families of spherical homoaromatics with both two and eight mobile electrons (including several neutral ZUSCHRIFTEN